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Sustainable groundwater management requires approaches to assess the influence of climate and management actions on the evolution of groundwater systems. Traditional approaches that apply continuity to assess groundwater sustainability fail to capture the spatial variability of aquifer responses. To address this gap, our study evaluates groundwater elevation data from the Coachella Valley, California, within a groundwater sustainability framework given the adoption of integrative management strategies in the valley. Our study details an innovative approach employing traditional statistical methods to improve understanding of aquifer responses. In this analysis, we evaluate trends at individual groundwater observation wells and regional groundwater behaviors using field significance. Regional elevation trends identified no significant trends during periods of intense groundwater replenishment, active since 1973, despite spatial variability in individual well trends. Our results illustrate the spatially limited effects of groundwater replenishment occur against a setting of long-term groundwater depletion, raising concerns over the definition of sustainable groundwater management in aquifer systems employing integrative management strategies.

BACKGROUND: Grapefruit juice (GFJ) enhances the systemic exposure of numerous CYP3A4 drug substrates, including felodipine, by inhibiting intestinal (but not hepatic) first-pass metabolism. Furanocoumarins have been identified as major CYP3A4 inhibitors contained in the juice, but their contribution to the GFJ effect in vivo remains unclear. OBJECTIVE: To ascertain whether furanocoumarins mediate the GFJ-felodipine interaction, a furanocoumarin-free GFJ was created and tested against orange juice and the original GFJ with respect to the oral pharmacokinetics of felodipine. DESIGN: With the use of food-grade solvents and absorption resins, furanocoumarins were removed ( approximately 99%) from whole GFJ, whereas other major ingredients (flavonoids) were retained. In an open, 3-way, randomized crossover design, 18 healthy volunteers ingested felodipine (10 mg) with 1 of the 3 juices (240 mL). Blood was collected over 24 h. At least 1 wk elapsed between juice treatments. RESULTS: The median and range of the area under the curve and the maximum concentration of felodipine were significantly (P < 0.001) greater with consumption of GFJ [110 (range: 58-270) nmol x h/L and 21 (7.6-50) nmol/L, respectively] than with that of orange juice [54 (29-150) nmol x h/L and 7.6 (3.4-13.9) nmol/L, respectively] or furanocoumarin-free GFJ [48 (23-120) nmol x h/L and 8.3 (3.0-16.6) nmol/L, respectively]. GFJ, orange juice, and furanocoumarin-free GFJ did not differ significantly (P > 0.09) in median time to reach maximum plasma concentration [2.5 (1.5-6), 2.8 (1.5-4), and 2.5 (2-6) h, respectively] or terminal half-life [6.6 (4.2-13.6), 7.8 (4.4-13.2), and 6.8 (2.6-14.4) h, respectively]. CONCLUSION: Furanocoumarins are the active ingredients in GFJ responsible for enhancing the systemic exposure of felodipine and probably other CYP3A4 substrates that undergo extensive intestinal first-pass metabolism. Copyright © 2006 American Society for Nutrition [ABSTRACT FROM AUTHOR]

Objectives : Addressing extensive and deep burn wounds poses considerable challenges for both patients and surgeons. The NovoSorb ® Biodegradable Temporizing Matrix (BTM) emerged as a novel dermal substitute and has been subjected to evaluation in large burn wound cases, with a specific focus on identifying risk factors associated with suboptimal take rates. Methods : All patients with burn wounds greater than 10% body surface that underwent BTM treatment between March 2020 and November 2023 were eligible for inclusion. Univariate analyses and linear regression models were employed to discern risk factors and predictors influencing the take rates of both the BTM and split-thickness skin grafts (STSGs). Results : A total of 175 patients (mean age 56.2 ± 19.8 years, 70.3% male) were evaluated. The mean take rates of the BTM and STSGs were 82.0 ± 24.7% and 87.3 ± 19.0%, respectively. There were significant negative correlations between BTM take and the number of surgeries before BTM application (r = -0.19, p = 0.01), %TBSA and STSG take (r = -0.36, p = <0.001) and significant positive correlations between BTM and STSG take (r = 0.41, p ≤ 0.001) in addition to NPWT and STSG take (r = 0.21, p = 0.01). Multivariate regression analyses showed that a larger number of surgeries prior to BTM application (OR -3.41, 95% CI -6.82, -0.03, p = 0.04) was associated with poorer BTM take. Allograft treatment before BTM application (OR -14.7, 95% CI -23.0, -6.43, p = 0.01) and failed treatment with STSG before BTM application (OR -20.8, 95% CI -36.3, -5.23, p ≤ 0.01) were associated with poorer STSG take, whereas higher BTM take rates were associated with overall higher STSG take (OR -0.15, 95% 0.05, 0.26, p = 0.01). The Meek technique was used in 24 patients and showed similar take rates (BTM: 76.3 ± 28.0%, p = 0.22; STSG: 80.7 ± 21.1, p = 0.07). Conclusions : This study summarizes our findings on the application of a BTM in the context of large burn wounds. The results demonstrate that successful treatment can be achieved even in patients with extensive burns, resulting in satisfying take rates for both the BTM and STSG. The data underscore the importance of promptly applying a BTM to debrided wounds and indicate good results when using Meek.

Introduction: Extensive full-thickness soft-tissue defects remain a challenge in reconstructive surgery. NovoSorb® Biodegradable Temporising Matrix (BTM) represents a novel dermal substitute and was evaluated in wounds deriving from different aetiologies and to highlight risk factors for poor take rates., Methods: All patients treated with BTM at our department between March 2020 and October 2022 were included. Differences in univariate and linear regression models identified predictors and risk factors for take rates of BTM and split-thickness skin grafts (STSG)., Results: Three hundred patients (mean age 54.2 ± 20.1 years, 66.3% male, 59.7% burns, 19.7% trauma and 20.6% others) were evaluated. Mean take rates of BTM and STSG after BTM delamination were 82.7 ± 25.2% and 86.0 ± 22.6%, respectively. Multiple regression analyses showed that higher body mass index (BMI, OR 0.43, 95% CI 0.86, -0.01, p = 0.44), prior allograft transplantation (OR 15.12, 95% CI 26.98, -3.31, p = 0.041), longer trauma-to-BTM-application intervals (OR 0.01, 95% CI 0.001, -0.001, p = 0.038), positive wound swabs before BTM (OR 7.15, 95% CI 13.50, -0.80, p = 0.028) and peripheral artery disease (OR 10.80, 95% CI 18.63, -2.96, p = 0.007) were associated with poorer BTM take. Higher BMI (OR 0.40, 95% CI 0.76, -0.08, p = 0.026), increasing BTM graft surface areas (OR 0.58, 95% CI -1.00, -0.17, p = 0.005), prior allograft (OR 12.20, 95% CI -21.99, -2.41, p = 0.015) or autograft transplantations (OR 22.42, 95% CI 38.69, -6.14, p = 0.001), tumour as the aetiology of the wound (OR 37.42, 95% CI 57.41, -17.83, p = 0.001), diabetes (OR 6.64, 95% CI 12.80, -0.48, p = 0.035) and impaired kidney function (OR 5.90, 95% CI 10.94, -0.86, p = 0.021) were associated with poorer STSG take after delamination of BTM, whereas higher BTM take rates were associated with better STSG take (OR 0.40, 95% CI 0.31,0.50, p < 0.001)., Conclusion: Extensive complex wounds of different aetiologies unsuitable for immediate STSG can be successfully reconstructed by means of two-staged BTM application and subsequent skin grafting. Importantly, presence of wound contamination or infection and prior allograft coverage appear to jeopardise good BTM and STSG take., (Copyright © 2024. Published by Elsevier Ltd.)

Observing basin water storage response due to hydroclimatic fluxes and human water use provides valuable insight to the sensitivity of water storage to climate change. Quantifying basin water storage changes due to climate and human water use is critical for water management yet remains a challenge globally. Observations from the Gravity Recovery and Climate Experiment (GRACE) mission are used to extract monthly available water (AW), representing the combined storage changes from groundwater and surface water stores. AW is combined with hydroclimatic fluxes, including precipitation (P) and evapotranspiration (ET) to quantify the hydroclimatic elasticity of AW for global basins. Our results detect consequential global water sensitivity to changes in hydroclimatic fluxes, where 25 % of land areas exhibit hydroclimatic elasticity of AW >10, implying that a 1 % change in monthly P-ET would result in a 10 % change in AW. Corroboration using a Budyko-derived metric substantiates our findings, demonstrating that basin water storage resilience to short-term water deficits is linked to basin partitioning predictability, and uniform seasonality of hydroclimatic fluxes. Our study demonstrates how small shifts in hydroclimate flux may affect available water storage potentially impacting billions globally., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Multiple lines of evidence suggest a central role for the endocannabinoid system (ECS) in the neuronal development and cognitive function and in the pathogenesis of fragile X syndrome (FXS). This review describes the ECS, its role in the central nervous system, how it is dysregulated in FXS, and the potential role of cannabidiol as a treatment for FXS. FXS is caused by deficiency or absence of the fragile X messenger ribonucleoprotein 1 (FMR1) protein, FMRP, typically due to the presence of >200 cytosine, guanine, guanine sequence repeats leading to methylation of the FMR1 gene promoter. The absence of FMRP, following FMR1 gene-silencing, disrupts ECS signaling, which has been implicated in FXS pathogenesis. The ECS facilitates synaptic homeostasis and plasticity through the cannabinoid receptor 1, CB 1 , on presynaptic terminals, resulting in feedback inhibition of neuronal signaling. ECS-mediated feedback inhibition and synaptic plasticity are thought to be disrupted in FXS, leading to overstimulation, desensitization, and internalization of presynaptic CB 1 receptors. Cannabidiol may help restore synaptic homeostasis by acting as a negative allosteric modulator of CB 1 , thereby attenuating the receptor overstimulation, desensitization, and internalization. Moreover, cannabidiol affects DNA methylation, serotonin 5HT 1A signal transduction, gamma-aminobutyric acid receptor signaling, and dopamine D 2 and D 3 receptor signaling, which may contribute to beneficial effects in patients with FXS. Consistent with these proposed mechanisms of action of cannabidiol in FXS, in the CONNECT-FX trial the transdermal cannabidiol gel, ZYN002, was associated with improvements in measures of social avoidance, irritability, and social interaction, particularly in patients who are most affected, showing ≥90% methylation of the FMR1 gene., (© 2023. The Author(s).)

Nicotine is the principal alkaloid in tobacco and has been the primary subject of scientific investigation for its pharmacological effects contributing to tobacco use, dependence, withdrawal, and physical harm. Related minor alkaloids, accounting for less than 6% of alkaloid content in tobacco leaves, may also mirror some of the same pharmacological effects. To detect such low concentrations of the minor alkaloids, tobacco product methods produced by the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) using gas chromatography and flame ionization detection (GC-FID) have been adapted for use with gas chromatography-mass spectrometry (GC-MS). Nicotine and minor alkaloid content in SPECTRUM Nicotine Research Cigarettes (NRC) have previously been determined using GC-FID; however, the minor alkaloids were unable to be detected or quantitated. This study employed UltraPerformance Convergence Chromatography (UPC 2 ) system coupled with tandem mass spectrometry (MS 2 ) to determine the nicotine and minor alkaloid content in NRC tobacco products. CORESTA Recommended Methods (CRMs) were adapted for their sample preparative procedures for optimal extraction followed by detection with UPC 2 -MS 2 . These results were compared to two separate CRMs that used GC-FID and GC-MS 2 as well as an alternative method with GC-MS 2 detection. The GC-FID and GC-MS 2 CRM preparations along with the alternative GC-MS 2 were unable to detect the analytes in every NRC formulation, whereas the UPC 2 -MS 2 extraction and detection method was able to quantify every analyte in every NRC formulation. This increased sensitivity demonstrates the utility of the UPC 2 -MS 2 analytical method in accurately detecting and quantifying nicotine and minor alkaloids in tobacco filler., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Autologous immediate breast reconstruction in large and ptotic breasts remains challenging. We aimed to identify independent risk factors for impaired wound healing and nipple necrosis after skin reducing wise pattern mastectomy in autologous reconstruction with an auxiliary deepithelialized inferiorly based dermal flap (IBDF)., Methods: This retrospective study examined patients with wise pattern mastectomy with autologous immediate breast reconstruction (IBR) between 2017 and 2019. All cases of large and ptotic breasts were included. Demographic, oncologic, reconstructive, and surgical data were compiled, and multifactorial binary logistic regression models identified independent predictors for skin complications and nipple areolar complex (NAC) necrosis., Results: Of 591 autologous breast reconstructions, 62 (11%) met the inclusion criteria. Overall wound complication rate was 32% ( n = 20, DIEP 11, thigh 9, p = 0.99), including 26% minor ( n = 16, non-surgically treated) and 7% major complications ( n = 4, surgically treated). Complete NAC necrosis occurred in one case. Nipple sparing mastectomy (NSM) ( p = 0.003), high BMI ( p = 0.019), longer operation time ( p = 0.044) and higher patient age ( p = 0.045) were independent risk factors for skin complications. Using internal mammary artery perforators (IMAP) as recipient vessels did not result in increased complication rates ( p = 0.59)., Conclusion: Higher patient age, BMI, and operation time (OT) significantly increase the risk for skin complications in combined reduction wise pattern mastectomies with autologous IBR. In this context, IBDFs help preserve the inframammary fold, providing vasculature to the T-junction and the mastectomy skin flaps. Acceptable complication rates can be achieved in large and ptotic breasts, regardless of preoperative chemotherapy or radiation. Gentle tissue handling with minimal thermal trauma preserves internal mammary artery perforators (IMAPs) as recipient vessels. In cases of flap failure and alloplastic conversion, the IBDF can serve as an autoderm, protecting the implant from exposure.

Neutral antagonists of GPCRs remain relatively rare-indeed, a large majority of GPCR antagonists are actually inverse agonists. The synthetic cannabinoid receptor agonist (SCRA) EG-018 was recently reported as a low efficacy cannabinoid receptor agonist. Here we report a comparative characterization of EG-018 and 13 analogues along with extant putative neutral antagonists of CB 1 . In HEK cells stably expressing human CB 1 , assays for inhibition of cAMP were performed by real-time BRET biosensor (CAMYEL), G protein cycling was quantified by [ 35 S]GTPγS binding, and stimulation of pERK was characterized by AlphaLISA (PerkinElmer). Signaling outcomes for the EG-018 analogues were highly variable, ranging from moderate efficacy agonism with high potency, to marginal agonism at lower potency. As predicted by differing pathway sensitivities to differences in ligand efficacy, most EG-018-based compounds were completely inactive in pERK alone. The lowest efficacy analogue in cAMP assays, 157, had utility in antagonism assay paradigms. Developing neutral antagonists of the CB 1 receptor has been a long-standing research goal, and such compounds would have utility both as research tools and in therapeutics. Although these results emphasize again the importance of system factors in determining signaling outcomes, some compounds characterized in this study appear among the lowest efficacy agonists described to date and therefore suggest that development of neutral antagonists is an achievable goal for CB 1 ., (© 2022 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.)

The Sterling Research Group identified pravadoline as an aminoalkylindole (AAI) non-steroidal anti-inflammatory pain reliever. As drug design progressed, the ability of AAI analogs to block prostaglandin synthesis diminished, and antinociceptive activity was found to result from action at the CB 1 cannabinoid receptor, a G-protein-coupled receptor (GPCR) abundant in the brain. Several laboratories applied computational chemistry methods to ultimately conclude that AAI and cannabinoid ligands could overlap within a common binding pocket but that WIN55212-2 primarily utilized steric interactions via aromatic stacking, whereas cannabinoid ligands required some electrostatic interactions, particularly involving the CB 1 helix-3 lysine. The Huffman laboratory identified strategies to establish CB 2 receptor selectivity among cannabimimetic indoles to avoid their CB 1 -related adverse effects, thereby stimulating preclinical studies to explore their use as anti-hyperalgesic and anti-allodynic pharmacotherapies. Some AAI analogs activate novel GPCRs referred to as "Alkyl Indole" receptors, and some AAI analogs act at the colchicine-binding site on microtubules. The AAI compounds having the greatest potency to interact with the CB 1 receptor have found their way into the market as "Spice" or "K2". The sale of these alleged "herbal products" evades FDA consumer protections for proper labeling and safety as a medicine, as well as DEA scheduling as compounds having no currently accepted medical use and a high potential for abuse. The distribution to the public of potent alkyl indole synthetic cannabimimetic chemicals without regard for consumer safety contrasts with the adherence to regulatory requirements for demonstration of safety that are routinely observed by ethical pharmaceutical companies that market medicines.

The non-nicotine constituents of tobacco may alter the reinforcing effects of nicotine, but the quantitative and qualitative profiles of these chemicals in tobacco products such as electronic cigarettes (e-cigarettes), cigars, and waterpipe tobacco are not well characterized. The objective of this work was to develop and validate analytical methods to utilize saline both as an extraction solvent for smoke condensates from cigarettes, little cigars, and waterpipe tobacco and aerosols from e-cigarettes and as a delivery vehicle of nicotine and non-nicotine constitents for nonclinical pharmacological studies. Ultrahigh-performance liquid chromatography was used to analyze nicotine and acetaldehyde, and a novel ultraperformance convergence chromatography-tandem mass spectrometry method was developed to analyze anabasine, anatabine, cotinine, myosmine, nornicotine, harmane, and norharmane. Linearity was confirmed for each standard curve with correlation coefficients ( r ) ≥ 0.99, and relative errors (RE) for the standards were ≤±10% over the calibration ranges. Method validation was performed by preparing triplicate samples in saline to mimic the composition and concentration of each analyte in the smoke or aerosol condensate and were used to determine method accuracy and precision. Relative standard deviation values were ≤15% and mean RE ≤15% for each analyte at each concentration level. Selectivity of the methods was demonstrated by the absence of peaks in blank vehicle or diluent samples. Storage stability was assessed over ∼45 days. Precision (%RSD ≤ 13) and recovery (percent of day 0 ≥ 80%) indicated that the saline formulations of all four products could be considered stable for up to ∼45 days at 4-8 °C. Therefore, the use of saline both as an extraction solvent and as a delivery vehicle adds versatility and improved performance in the study of the pharmacological effects of constituents from mainstream smoke and aerosols generated from cigarettes, little cigars, waterpipes, and e-cigarettes.

Competing Interests: M.H.L. reports personal fees, nonfinancial support, and other from Canopy Growth Corporation and GW Pharmaceuticals outside the submitted study. L.M. reports personal fees, nonfinancial support, and other from Canopy Growth Corporation and Canopy Health Innovations Inc., outside the submitted study. B.F.T. reports personal fees, nonfinancial support, and other from Canopy Growth Corporation, personal fees and nonfinancial support from Elsevier and Research Triangle Institute, nonfinancial support from Curaleaf, outside the submitted study. E.N.P. reports personal fees, nonfinancial support, and other from Canopy Growth Corporation, and personal fees from Battelle outside the submitted study. M.O.B.-M. reports personal fees, nonfinancial support, and other from Canopy Growth Corporation and Zynerba Pharmaceuticals, personal fees from Tilray, personal fees and nonfinancial support from AusCann Group Ltd., Realm of Caring Foundation, and The Lambert Center for the Study of Medicinal Cannabis and Hemp, outside the submitted study.

Human SH-SY5Y neuroblastoma cells stably expressing exogenous CB 1 (CB 1 XS) or CB 2 (CB 2 XS) receptors were developed to investigate endocannabinoid signaling in the extension of neuronal projections. Expression of cannabinoid receptors did not alter proliferation rate, viability, or apoptosis relative to parental SH-SY5Y. Transcripts for endogenous cannabinoid system enzymes (diacylglycerol lipase, monoacylglycerol lipase, α/β-hydrolase domain containing proteins 6 and 12, N-acyl phosphatidylethanolamine-phospholipase D, and fatty acid amide hydrolase) were not altered by CB 1 or CB 2 expression. Endocannabinoid ligands 2-arachidonoylglycerol (2-AG) and anandamide were quantitated in SH-SY5Y cells, and diacylglycerol lipase inhibitor tetrahydrolipstatin decreased 2-AG abundance by 90% but did not alter anandamide abundance. M3 muscarinic agonist oxotremorine M, and inhibitors of monoacylglycerol lipase and α/β hydrolase domain containing proteins 6 &12 increased 2-AG abundance. CB 1 receptor expression increased lengths of short (<30 μm) and long (>30 μm) projections, and this effect was significantly reduced by tetrahydrolipstatin, indicative of stimulation by endogenously produced 2-AG. Pertussis toxin, Gβγ inhibitor gallein, and β-arrestin inhibitor barbadin did not significantly alter long projection length in CB 1 XS, but significantly reduced short projections, with gallein having the greatest inhibition. The rho kinase inhibitor Y27632 increased CB 1 receptor-mediated long projection extension, indicative of actin cytoskeleton involvement. CB 1 receptor expression increased GAP43 and ST8SIA2 mRNA and decreased ITGA1 mRNA, whereas CB 2 receptor expression increased NCAM and SYT mRNA. We propose that basal endogenous production of 2-AG provides autocrine stimulation of CB 1 receptor signaling through Gi/o, Gβγ, and β-arrestin mechanisms to promote neuritogenesis, and rho kinase influences process extension., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Synthetic cannabinoid receptor agonists (SCRAs) possess high abuse liability and complex toxicological profiles, making them serious threats to public health. EG-018 is a SCRA that has been detected in both illicit products and human samples, but it has received little attention to date. The current studies investigated EG-018 at human CB 1 and CB 2 receptors expressed in HEK293 cells in [ 3 H]CP55,940 competition binding, [ 35 S]GTPγS binding and forskolin-stimulated cAMP production. EG-018 was also tested in vivo for its ability to produce cannabimimetic and abuse-related effects in the cannabinoid tetrad and THC drug discrimination, respectively. EG-018 exhibited high affinity at CB 1 (21 nM) and at CB 2 (7 nM), but in contrast to typical SCRAs, behaved as a weak partial agonist in [ 35 S]GTPγS binding, exhibiting lower efficacy but greater potency, than that of THC at CB 1 and similar potency and efficacy at CB 2 . EG-018 inhibited forskolin-stimulated cAMP with similar efficacy but lower potency, compared to THC, which was likely due to high receptor density facilitating saturation of this signaling pathway. In mice, EG-018 (100 mg/kg, 30 min) administered intraperitoneally (i.p.) did not produce effects in the tetrad or drug discrimination nor did it shift THC's ED 50 value in drug discrimination when administered before THC, suggesting EG-018 has negligible occupancy of brain CB 1 receptors following i.p. administration. Following intravenous (i.v.) administration, EG-018 (56 mg/kg) produced hypomotility, catalepsy, and hypothermia, but only catalepsy was blocked by the selective CB 1 antagonist rimonabant (3 mg/kg, i.v.). Additional studies of EG-018 and its structural analogues could provide further insight into how cannabinoids exert efficacy through the cannabinoid receptors., (Copyright © 2020 Elsevier Inc. All rights reserved.)

We previously reported diarylurea derivatives as cannabinoid type-1 receptor (CB 1 ) allosteric modulators, which were effective in attenuating cocaine-seeking behavior. Herein, we extended the structure-activity relationships of PSNCBAM-1 ( 2 ) at the central phenyl ring directly connected to the urea moiety. Replacement with a thiophene ring led to 11 with improved or comparable potencies in calcium mobilization, [ 35 S]GTPγS binding, and cAMP assays, whereas substitution with nonaromatic rings led to significant attenuation of the modulatory activity. These compounds had no inverse agonism in [ 35 S]GTPγS binding, a characteristic that is often thought to contribute to adverse psychiatric effects. While 11 had good metabolic stability in rat liver microsomes, it showed modest solubility and blood-brain barrier permeability. Compound 11 showed an insignificant attenuation of cocaine seeking behavior in rats, most likely due to its limited CNS penetration, suggesting that pharmacokinetics and distribution play a role in translating the in vitro efficacy to in vivo behavior.

Background: Use of electronic cigarettes (e-cigarettes) has increased exponentially since their appearance on the U.S. market around 2007. To provide preclinical models of vaping that incorporate olfactory cues and chemosensory effects (including flavors) that play a role in human vaping behavior, the feasibility of using a modified e-cigarette device for delivery of aerosolized nicotine was examined in a nicotine discrimination procedure in mice., Methods: Adult female and male C57BL/6 mice were trained to discriminate 0.75 mg/kg subcutaneous (s.c.) nicotine from saline. After determination of a s.c. nicotine dose-effect curve, aerosolized freebase nicotine and nicotine-containing tobacco products (i.e., non-flavored and Arctic Blast e-liquids) were evaluated., Results: Nicotine (s.c.) dose-dependently substituted in mice of both sexes, although females showed less sensitivity and greater variability. By contrast, aerosolized nicotine, regardless of formulation, produced concentration-dependent increases up to maximum of 46-62% nicotine-associated responding. Brain nicotine concentrations for each sex were similar for s.c. 0.75 mg/kg nicotine and 30 mg/ml freebase nicotine., Conclusions: Mice of both sexes readily acquired s.c. nicotine discrimination, but females showed less sensitivity. Further, all three formulations of aerosolized nicotine produced increases in nicotine-like responding in mice of each sex. However, the maximum magnitude of these increases did not engender a similar degree of substitution as s.c. 0.75 mg/kg nicotine, despite similar brain concentrations of nicotine at 30 mg/ml aerosolized nicotine. Additional research is needed for determination of the reason(s); however, results here demonstrate initial feasibility for examination of the discriminative stimulus effects of vaped drugs such as nicotine., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The pharmacological effects of tobacco products are primarily mediated by nicotine; however, research suggests that several non-nicotine tobacco constituents may alter the reinforcing effects of nicotine. This study evaluated the reinforcing effects of aqueous solutions of smoke/aerosol condensate from cigarettes, little cigars, electronic cigarettes (e-cigarettes), and waterpipe tobacco in a self-administration procedure to determine if abuse liability of these tobacco products differed. Adult male Sprague-Dawley rats (n = 64 total) were trained to self-administer intravenous nicotine (30 μg/kg/infusion) on a fixed ratio 5 schedule of reinforcement. Following nicotine dose-effect assessment (1, 7.5, 15, and 30 μg/kg/infusion), rats were given access to smoke/aerosol condensate derived from their assigned tobacco product. Rats responded for smoke/aerosol condensate containing 1, 7.5, 15, and 30 μg/kg/infusion nicotine, with the ratio of nicotine:non-nicotine constituents held constant across doses for each tobacco product. Responding for nicotine or smoke/aerosol condensate was also assessed on a progressive ratio schedule of reinforcement. Cigarette, little cigar, and e-cigarette smoke/aerosol condensates shifted the nicotine dose-effect curve leftward, whereas waterpipe tobacco smoke condensate shifted the dose-effect curve rightward. Smoke/aerosol condensate from all tobacco products produced similar levels of responding compared to nicotine alone during the progressive ratio phase. Results suggest that non-nicotine constituents in cigarettes, little cigars, and e-cigarettes differentially enhance nicotine's reinforcing potency. In contrast, waterpipe tobacco blunted nicotine's reinforcing potency, suggesting that it may contain unique constituents that dampen nicotine's reinforcing effects., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A recent push to provide more translationally relevant preclinical models for examination of pharmacological mechanisms underlying inhaled substances of abuse has resulted in the development of equipment and methods that allows exposure of freely moving rodents to aerosolized psychoactive drugs. In the present study, synthetic cannabinoids (CP55,940, AB-CHMINACA, and AMB-FUBINACA) were administered intraperitoneally (i.p.) or aerosolized via a modified electronic cigarette device. Subsequently, the compounds were evaluated in adult male and female C57/Bl6 mice trained to discriminate i.p. 5.6 mg/kg Δ 9 -tetrahydrocannabinol (THC) for food reinforcement. When administered i.p., THC and AB-CHMINACA were equally potent at producing THC-like effects in both sexes, but CP55,940 and AMB-FUBINACA were more potent in males. Upon aerosol exposure, all compounds continued to produce THC-like effects in both sexes, with AMB-FUBINACA remaining the most potent. In contrast, aerosolized CP55,940 showed substantial decreases in potency in both sexes. Aerosolized nicotine did not substitute for THC in either sex. In females, aerosolized cumyl-4CN-BINACA produced concentration-dependent increases in responding on the THC-associated nosepoke. In addition, the effects of an active concentration of AMB-FUBINACA were reversed by rimonabant, suggesting CB 1 receptor mediation. These results show that synthetic cannabinoids produce THC-like effects when injected i.p. or after aerosolization. This study adds to a growing literature suggesting that evaluation of abuse liability of substances via aerosol exposure is feasible and may provide a translationally relevant method that allows for investigation of factors important to the abuse of drugs which humans typically smoke or vape., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Depletion of groundwater resources has been identified in numerous global aquifers, suggesting that extractions have exceeded natural recharge rates in critically important global freshwater supplies. Groundwater depletion has been ascribed to groundwater pumping, often ignoring influences of direct and indirect consequences of climate variability. Here, we explore relations between natural and human drivers and spatiotemporal changes in groundwater storage derived from the Gravity Recovery and Climate Experiment (GRACE) satellites using regression procedures and dominance analysis. Changes in groundwater storage are found to be influenced by direct climate variability, whereby groundwater recharge and precipitation exhibited greater influence as compared to groundwater pumping. Weak influence of groundwater pumping may be explained, in part, by quasi-equilibrium aquifer conditions that occur after "long-time" pumping, while precipitation and groundwater recharge records capture groundwater responses linked to climate-induced groundwater depletion. Evaluating groundwater response to climate variability is critical given the reliance of groundwater resources to satisfy water demands and impending changes in climate variability that may threaten future water availability.

Synthetic cannabinoids (SCs) are novel psychoactive substances that are easily acquired, widely abused as a substitute for cannabis, and associated with cardiotoxicity and seizures. Although the structural bases of these compounds are scaffolds with known affinity and efficacy at the human cannabinoid type-1 receptor (hCB 1 ), upon ingestion or inhalation they can be metabolized to multiple chemical entities of unknown pharmacological activity. A large proportion of these metabolites are hydroxylated on the pentyl chain, a key substituent that determines receptor affinity and selectivity. Thus, the pharmacology of SC metabolites may be an important component in understanding the in vivo effects of SCs. We examined nine SCs (AB-PINACA, 5F-AB-PINACA, ADB/MDMB-PINACA, 5F-ADB, 5F-CUMYL-PINACA, AMB-PINACA, 5F-AMB, APINACA, and 5F-APINACA) and their hydroxypentyl (either 4-OH or 5-OH) metabolites in [ 3 H]CP55,940 receptor binding and the [ 35 S]GTP γ S functional assay to determine the extent to which these metabolites retain activity at cannabinoid receptors. All of the SCs tested exhibited high affinity (<10 nM) and efficacy for hCB 1 and hCB 2 The majority of the hydroxypentyl metabolites retained full efficacy at hCB 1 and hCB 2 , albeit with reduced affinity and potency, and exhibited greater binding selectivity for hCB 2 These data suggest that phase I metabolites may be contributing to the in vivo pharmacology and toxicology of abused SCs. Considering this and previous reports demonstrating that metabolites retain efficacy at the hCB 1 receptor, the full pharmacokinetic profiles of the parent compounds and their metabolites need to be considered in terms of the pharmacological effects and time course associated with these drugs., (Copyright © 2019 by The American Society for Pharmacology and Experimental Therapeutics.)

Allosteric modulators have attracted significant interest as an alternate strategy to modulate CB 1 receptor signaling for therapeutic benefits that may avoid the adverse effects associated with orthosteric ligands. Here we extended our previous structure-activity relationship studies on the diarylurea-based CB 1 negative allosteric modulators (NAMs) by introducing five-membered heterocycles to replace the 5-pyrrolidinylpyridinyl group in PSNCBAM-1 (1), one of the first generation CB 1 allosteric modulators. Many of these compounds had comparable potency to 1 in blocking the CB 1 agonist CP55,940 stimulated calcium mobilization and [ 35 S]GTP-γ-S binding. Similar to 1, most compounds showed positive cooperativity by increasing [ 3 H]CP55,940 binding, consistent with the positive allosteric modulator (PAM)-antagonist mechanism. Interestingly, these compounds exhibited differences in ability to increase specific binding of [ 3 H]CP55,940 and decrease binding of the antagonist [ 3 H]SR141716. In saturation binding studies, only increases in [ 3 H]CP55,940 B max , but not K d , were observed, suggesting that these compounds stabilize low affinity receptors into a high affinity state. Among the series, the 2-pyrrolyl analogue (13) exhibited greater potency than 1 in the [ 35 S]GTP-γ-S binding assay and significantly enhanced the maximum binding level in the [ 3 H]CP5,5940 binding assay, indicating greater CB 1 receptor affinity and/or cooperativity.

Purpose: The use of novel synthetic cannabinoids as intoxicants continues in spite of associated health risks. These compounds are typically smoked or vaporized, but many synthetic cannabinoids contain thermally labile chemical moieties. This study investigated the thermal stability six carboxamide-type synthetic cannabinoids (CUMYL-PICA, 5F-CUMYL-PICA, AMB-FUBINACA, MDMB-FUBINACA, NNEI, and MN-18) in order to characterise potential user exposure to thermolysis products., Methods: Compounds were heated sequentially to 200, 400, 600 and 800 °C using a thermolysis probe, and the resultant thermolysis products were analysed via GC-MS. A secondary analysis quantified thermolytically generated cyanide via LC-MS/MS., Results: All six synthetic cannabinoids underwent thermal degradation when heated above 400 °C, and released a variety of potentially toxic products, including toluene, naphthalene, and 1-naphthalamine. Compound-specific degradants were tentatively identified together with a general degradative pathway for carboxamide-type synthetic cannabinoids, which proceeds via indole- or indazole-amide formation and subsequent dehydration to an indole- or indazole-carbonitrile. This degradative pathway culminated in the thermolytic liberation of cyanide, in amounts up to 27 μg per mg of starting material., Conclusions: People who smoke carboxamide-type synthetic cannabinoids are likely to be exposed to range of potentially toxic thermal degradants, including cyanide. These degradants could have significant health impacts in human users., Competing Interests: Conflict of interest The authors have no conflict of interest to declare.

The Cannabinoid CB1 Receptor (CB1R) is involved in a variety of physiological pathways and has long been considered a golden target for therapeutic manipulation. A large body of evidence in both animal and human studies suggests that CB1R antagonism is highly effective for the treatment of obesity, metabolic disorders and drug addiction. However, the first-in-class CB1R antagonist/inverse agonist, rimonabant, though demonstrating effectiveness for obesity treatment and smoking cessation, displays serious psychiatric side effects, including anxiety, depression and even suicidal ideation, resulting in its eventual withdrawal from the European market. Several strategies are currently being pursued to circumvent the mechanisms leading to these side effects by developing neutral antagonists, peripherally restricted ligands, and allosteric modulators. In this review, we describe the progress in the development of therapeutics targeting the CB1R in the last two decades., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: The recent NIH mandate to consider sex as a biological variable in preclinical research has focused attention on delineation of sex differences in behavior. To investigate mechanisms underlying sex differences in Δ 9 -tetrahydrocannabinol (THC) effects, we examined the effects of sex and gonadal hormones on CB 1 receptors in cerebellum, hippocampus, prefrontal cortex, and striatum., Methods: Adult Sprague-Dawley rats underwent gonadectomy (GDX) or sham-GDX. Half of the GDX females and males received estradiol or testosterone replacement (GDX+H), respectively. All rats were injected with vehicle or 30 mg/kg THC twice daily for 1 week before brain collection. CP55,940-stimulated [ 35 S]GTPγS and [ 3 H]SR141716A saturation binding assays were performed., Results: With exception of enhanced receptor activation in the hippocampi of female rats compared to males, vehicle-treated rats exhibited minimal sex differences in CB 1 receptor densities or G-protein coupling. Repeated treatment with THC resulted in pronounced CB 1 receptor desensitization and downregulation in both sexes in all brain regions with a greater magnitude of change in females., Conclusions: These results suggest that sex differences in the density and G-protein coupling of brain CB 1 receptors may play a limited role in sex differences in acute THC effects not mediated by the hippocampus. In contrast, sex differences after repeated THC were common, with females (intact, GDX, and GDX+H) showing greater downregulation or desensitization in all four brain regions compared to the respective male groups. This result is consistent with a finding that women tend to progress to tolerance and dependence quicker than men after initiation of cannabis use., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Diversion of synthetic cannabinoids from the lab to drugs of abuse has become increasingly prevalent in recent years. Moreover, as earlier synthetic cannabinoids were banned, manufacturers introduced a new supply of novel compounds to serve as replacements. Hence, the chemical diversity of synthetic cannabinoid analogs has also rapidly increased. The present study examined 8 new synthetic cannabinoids: AM-1220, AM-2232, AM-2233, AM-679, EAM-2201, JWH-210, JHW-251, and MAM-2201. Each compound was assessed for binding affinity and functional activation of CB 1 and CB 2 receptors, and pharmacological equivalence with Δ 9 -tetrahydrocannabinol (THC) in THC drug discrimination. All compounds bound to and activated CB 1 and CB 2 receptors, although efficacy at the CB 2 receptor was reduced compared to that for the CB 1 receptor. Similarly, all compounds stimulated [ 35 S]GTPγS binding through the CB 1 receptor, and all compounds except AM-1220 and AM-2233 stimulated [ 35 S]GTPγS binding through the CB 2 receptor. Furthermore, these compounds, along with CP55,940, substituted for THC in THC drug discrimination. Rank order of potency in drug discrimination was correlated with CB 1 receptor binding affinity. Together, these results suggest that all test compounds share the THC-like subjective effects of marijuana. Interestingly, the most potent compounds in CB 1 binding in the present study were also the compounds that have been found recently in the U.S., MAM-2201, EAM-2201, JWH-210, AM-2233, and AM-1220. These results indicate that the evolution of the synthetic cannabinoid drug market may be focused toward compounds with increased potency. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.', (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Synthetic cannabinoids are a class of novel psychoactive substances that exhibit high affinity at the cannabinoid type-1 (CB 1 ) receptor and produce effects similar to those of Δ-9-tetrahydrocannabinol (THC), the primary psychoactive constituent of cannabis. Illicit drug manufacturers are continually circumventing laws banning the sale of synthetic cannabinoids by synthesizing novel structures and doing so with little regard for the potential impact on pharmacological and toxicological effects. Synthetic cannabinoids produce a wide range of effects that include cardiotoxicity, seizure activity, and kidney damage, and they can cause death. Six synthetic cannabinoids, recently detected in illicit preparations, MMB-FUBINACA, MDMB-FUBINACA, CUMYL-PICA, 5F-CUMYL-PICA, NNEI, and MN-18 were assessed for: 1) receptor binding affinity at the human CB 1 and human CB 2 receptors, 2) function in [ 35 S]GTP γ S and cAMP signaling, and 3) THC-like effects in a mouse drug discrimination assay. All six synthetic cannabinoids exhibited high affinity for human cannabinoid receptors type-1 and type-2 and produced greater maximal effects than THC in [ 35 S]GTP γ S and cAMP signaling. Additionally, all six synthetic cannabinoids substituted for THC in drug discrimination, suggesting they probably possess subjective effects similar to those of cannabis. Notably, MDMB-FUBINACA, a methylated analog of MMB-FUBINACA, had higher affinity for CB 1 than the parent, showing that minor structural modifications being introduced can have a large impact on the pharmacological properties of these drugs. This study demonstrates that novel structures being sold and used illicitly as substitutes for cannabis are retaining high affinity at the CB 1 receptor, exhibiting greater efficacy than THC, and producing THC-like effects in models relevant to subjective effects in humans., (Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.)

In 2014 and 2015, synthetic cannabinoid receptor agonists NNEI (N-1-naphthalenyl-1-pentyl-1H-indole-3-carboxamide) and MN-18 (N-1-naphthalenyl-1-pentyl-1H-indazole-3-carboxamide) were detected in recreationally used and abused products in multiple countries, and were implicated in episodes of poisoning and toxicity. Despite this, the pharmacokinetic profiles of NNEI and MN-18 have not been characterized. In the present study NNEI and MN-18 were incubated in rat and human liver microsomes and hepatocytes, to estimate kinetic parameters and to identify potential metabolic pathways, respectively. These parameters and pathways were then examined in vivo, via analysis of blood and urine samples from catheterized male rats following intraperitoneal (3 mg/kg) administration of NNEI and MN-18. Both NNEI and MN-18 were rapidly cleared by rat and human liver microsomes, and underwent a range of oxidative transformations during incubation with rat and human hepatocytes. Several unique metabolites were identified for the forensic identification of NNEI and MN-18 intake. Interestingly, NNEI underwent a greater number of biotransformations (20 NNEI metabolites versus 10 MN-18 metabolites), yet parent MN-18 was eliminated at a faster rate than NNEI in vivo. Additionally, in vivo elimination was more rapid than in vitro estimates. These data highlight that even closely related synthetic cannabinoids can possess markedly distinct pharmacokinetic profiles, which can vary substantially between in vitro and in vivo models., (Copyright © 2017 John Wiley & Sons, Ltd.)

While allosteric modulators of the cannabinoid type-1 receptor (CB 1 ) continue to be developed and characterized, the gap between the in vitro and in vivo data is widening, raising questions regarding translatability of their effects and biological relevance. Among the CB 1 allosteric modulators, PSNCBAM-1 has received little attention regarding its effects in vivo. Recently, pregnenolone was reported to act as an allosteric modulator of CB 1 , blocking THC's effects in vitro and in vivo, highlighting the potential of CB 1 allosteric modulators for treatment of cannabis intoxication. We investigated the pharmacological effects of PSNCBAM-1 and two structural analogs, RTICBM-15 and -28, as well as pregnenolone, in both signaling and behavioral assays including [ 35 S]GTPγS binding, the cannabinoid tetrad and drug discrimination. While the CB 1 allosteric modulator PSNCBAM-1 attenuated THC-induced anti-nociception and its structural analog RTICBM-28 reduced THC's potency in drug discrimination, most cannabinoid effects in mice were unaffected. In contrast to the mouse studies, PSNCBAM-1 and analogs insurmountably antagonized CP55,940- and THC-stimulated [ 35 S]GTPγS binding and exhibited negative binding cooperativity with [ 3 H]SR141716 with similar apparent affinities. Notably, RTICBM-28, which contains a cyano substitution at the 4-chlorophenyl position of PSNCBAM-1, exhibited enhanced binding cooperativity with CP55,940. In contrast to previous findings, pregnenolone did not block THC's effects in drug discrimination or [ 35 S]GTPγS. These data further highlight the difficulty in translating pharmacological effects of CB 1 allosteric modulators in vivo but confirm the established pharmacology of PSNCBAM-1 and analogs in molecular assays of CB 1 receptor function., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Allosteric modulators of the cannabinoid CB1 receptor have recently been reported as an alternative approach to modulate the CB1 receptor for therapeutic benefits. In this study, we report the design and synthesis of a series of diarylureas derived from PSNCBAM-1 (2). Similar to 2, these diarylureas dose-dependently inhibited CP55,940-induced intracellular calcium mobilization and [ 35 S]GTP-γ-S binding while enhancing [ 3 H]CP55,940 binding to the CB1 receptor. Structure-activity relationship studies revealed that the pyridinyl ring of 2 could be replaced by other aromatic rings and the pyrrolidinyl ring is not required for CB1 allosteric modulation. 34 (RTICBM-74) had similar potencies as 2 in all in vitro assays but showed significantly improved metabolic stability to rat liver microsomes. More importantly, 34 was more effective than 2 in attenuating the reinstatement of extinguished cocaine-seeking behavior in rats, demonstrating the potential of this diarylurea series as promising candidates for the development of relapse treatment of cocaine addiction.

Synthetic cannabinoids are sprayed onto plant material and smoked for their marijuana-like effects. Clandestine manufacturers modify synthetic cannabinoid structures by creating closely related analogs. Forensic laboratories are tasked with detection of these analog compounds, but targeted analytical methods are often thwarted by the structural modifications. Here, direct analysis in real time coupled to accurate mass time-of-flight mass spectrometry (DART-TOF-MS) in combination with liquid chromatography quadruple time-of-flight mass spectrometry (LC-QTOF-MS) are presented as a screening and nontargeted confirmation method, respectively. Methanol extracts of herbal material were run using both methods. Spectral data from four different herbal products were evaluated by comparing fragmentation pattern, accurate mass and retention time to available reference standards. JWH-018, JWH-019, AM2201, JWH-122, 5F-AKB48, AKB48-N-(4-pentenyl) analog, UR144, and XLR11 were identified in the products. Results demonstrate that DART-TOF-MS affords a useful approach for rapid screening of herbal products for the presence and identification of synthetic cannabinoids., (© 2017 American Academy of Forensic Sciences.)

Synthetic cannabinoids (SCs) represent an emerging class of abused drugs associated with psychiatric complications and other substantial health risks. These ligands are largely sold over the internet for human consumption, presumably because of their high cannabinoid 1 receptor (CB 1 R) affinity and their potency in eliciting pharmacological effects similar to Δ 9 -tetrahydrocannabinol (THC), as well as circumventing laws illegalizing this plant. Factors potentially contributing to the increased prevalence of SC abuse and related hospitalizations, such as increased CB 1 R efficacy and non-CB 1 R targets, highlight the need for quantitative pharmacological analyses to determine receptor mediation of the pharmacological effects of cannabinoids. Accordingly, the present study used pA 2 and pK B analyses for quantitative determination of CB 1 R mediation in which we utilized the CB 1 R-selective inverse agonist/antagonist rimonabant to elicit rightward shifts in the dose-response curves of five SCs (i.e., A-834,735D; WIN55,212-2; CP55,950; JWH-073; and CP47,497) and THC in producing common cannabimimetic effects (i.e., catalepsy, antinociception, and hypothermia). The results revealed overall similarity of pA 2 and pK B values for these compounds and suggest that CB 1 Rs, and not other pharmacological targets, largely mediated the central pharmacological effects of SCs. More generally, affinity estimation offers a powerful pharmacological approach to assess potential receptor heterogeneity subserving in vivo pharmacological effects of SCs., (Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.)

Recent decades have seen much progress in the identification and characterization of cannabinoid receptors and the elucidation of the mechanisms by which derivatives of the Cannabis sativa plant bind to receptors and produce their physiological and psychological effects. The information generated in this process has enabled better understanding of the fundamental physiological and psychological processes controlled by the central and peripheral nervous systems and has fostered the development of natural and synthetic cannabinoids as therapeutic agents. A negative aspect of this decades-long effort is the proliferation of clandestinely synthesized analogs as recreational street drugs with dangerous effects. Currently, the interactions of cannabinoids with their biochemical substrates are extensively but inadequately understood, and the clinical application of derived and synthetic receptor ligands remains quite limited. The wide anatomical distribution and functional complexity of the cannabinoid system continue to indicate potential for both therapeutic and side effects, which offers challenges and opportunities for medicinal chemists involved in drug discovery and development., Competing Interests: DECLARATION OF CONFLICTING INTERESTS: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosures and Ethics As a requirement of publication author(s) have provided to the publisher signed confirmation of compliance with legal and ethical obligations including, but not limited to, the following: authorship and contributorship, conflicts of interest, privacy and confidentiality and (where applicable) protection of human and animal research subjects. The authors have read and confirmed their agreement with the ICMJE authorship and conflict of interest criteria. The authors have also confirmed that this article is unique and not under consideration or published in any other publication, and that they have permission from rights holders to reproduce any copyrighted material. Any disclosures are made in this section. The external blind peer reviewers report no conflicts of interest.

The cannabinoid CB1 receptor is a G protein coupled receptor and plays an important role in many biological processes and physiological functions. A variety of CB1 receptor agonists and antagonists, including endocannabinoids, phytocannabinoids, and synthetic cannabinoids, have been discovered or developed over the past 20 years. In 2005, it was discovered that the CB1 receptor contains allosteric site(s) that can be recognized by small molecules or allosteric modulators. A number of CB1 receptor allosteric modulators, both positive and negative, have since been reported and importantly, they display pharmacological characteristics that are distinct from those of orthosteric agonists and antagonists. Given the psychoactive effects commonly associated with CB1 receptor agonists and antagonists/inverse agonists, allosteric modulation may offer an alternate approach to attain potential therapeutic benefits while avoiding inherent side effects of orthosteric ligands. This review details the complex pharmacological profiles of these allosteric modulators, their structure-activity relationships, and efforts in elucidating binding modes and mechanisms of actions of reported CB1 allosteric modulators. The ultimate development of CB1 receptor allosteric ligands could potentially lead to improved therapies for CB1-mediated neurological disorders., (© 2016 Wiley Periodicals, Inc.)

Smoking is the most common route of administration for cannabis; however, vaping cannabis extracts and synthetic cannabinoids ("fake marijuana") in electronic cigarette devices has become increasingly popular. Yet, most animal models used to investigate biological mechanisms underlying cannabis use employ injection as the route of administration. This study evaluated a novel e-cigarette device that delivers aerosolized cannabinoids to mice. The effects of aerosolized and injected synthetic cannabinoids (CP 55,940, AB-CHMINACA, XLR-11, and JWH-018) in mice were compared in a battery of bioassays in which psychoactive cannabinoids produce characteristic effects. The most potent cannabinoids (CP 55,940 and AB-CHMINACA) produced the full cannabinoid profile (ie, hypothermia, hypolocomotion, and analgesia), regardless of the route of administration. In contrast, aerosolized JWH-018 and XLR-11 did not produce the full profile of cannabimimetic effects. Results of time course analysis for hypothermia showed that aerosol exposure to CP 55,940 and AB-CHMINACA produced faster onset of effects and shorter duration of action than injection. The ability to administer cannabinoids to rodents using the most common route of administration among humans provides a method for collecting preclinical data with enhanced translational relevance., Competing Interests: DECLARATION OF CONFLICTING INTERESTS: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Synthetic cannabinoids are manufactured clandestinely with little quality control and are distributed as herbal "spice" for smoking or as bulk compound for mixing with a solvent and inhalation via electronic vaporizers. Intoxication with synthetic cannabinoids has been associated with seizure, excited delirium, coma, kidney damage, and other disorders. The chemical alterations produced by heating these structurally novel compounds for consumption are largely unknown. Here, we show that heating synthetic cannabinoids containing tetramethylcyclopropyl-ring substituents produced thermal degradants with pharmacological activity that varied considerably from their parent compounds. Moreover, these degradants were formed under conditions simulating smoking. Some products of combustion retained high affinity at the cannabinoid 1 (CB 1 ) and CB 2 receptors, were more efficacious than (-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol (CP55,940) in stimulating CB 1 receptor-mediated guanosine 5'-O-(3-thiotriphosphate) (GTPγS) binding, and were potent in producing Δ 9 -tetrahydrocannabinol-like effects in laboratory animals, whereas other compounds had low affinity and efficacy and were devoid of cannabimimetic activity. Degradants that retained affinity and efficacy also substituted in drug discrimination tests for the prototypical synthetic cannabinoid 1-pentyl-3-(1-naphthoyl)indole (JWH-018), and are likely to produce psychotropic effects in humans. Hence, it is important to take into consideration the actual chemical exposures that occur during use of synthetic cannabinoid formulations to better comprehend the relationships between dose and effect., (Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.)

Background: Although both men and women use e-cigarettes, most preclinical nicotine research has focused on its effects in male rodents following injection. The goals of the present study were to develop an effective e-cigarette nicotine delivery system, to compare results to those obtained after subcutaneous (s.c.) injection, and to examine sex differences in the model., Methods: Hypothermia and locomotor suppression were assessed following aerosol exposure or s.c. injection with nicotine in female and male mice. Subsequently, plasma and brain concentrations of nicotine and cotinine were measured., Results: Passive exposure to nicotine aerosol produced concentration-dependent and mecamylamine reversible hypothermic and locomotor suppressant effects in female and male mice, as did s.c. nicotine injection. In plasma and brain, nicotine and cotinine concentrations showed dose/concentration-dependent increases in both sexes following each route of administration. Sex differences in nicotine-induced hypothermia were dependent upon route of administration, with females showing greater hypothermia following aerosol exposure and males showing greater hypothermia following injection. In contrast, when they occurred, sex differences in nicotine and cotinine levels in brain and plasma consistently showed greater concentrations in females than males, regardless of route of administration., Discussion: In summary, the e-cigarette exposure device described herein was used successfully to deliver pharmacologically active doses of nicotine to female and male mice. Further, plasma nicotine concentrations following exposure were similar to those after s.c. injection with nicotine and within the range observed in human smokers. Future research on vaped products can be strengthened by inclusion of translationally relevant routes of administration., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Originally developed as research tools for use in structure-activity relationship studies, synthetic cannabinoids contributed to significant scientific advances in the cannabinoid field. Unfortunately, a subset of these compounds was diverted for recreational use beginning in the early 2000s. As these compounds were banned, they were replaced with additional synthetic cannabinoids with increasingly diverse chemical structures. This chapter focuses on integration of recent results with those covered in previous reviews. Whereas most of the early compounds were derived from the prototypic naphthoylindole JWH-018, currently popular synthetic cannabinoids include tetramethylcyclopropyl ketones and indazole-derived cannabinoids (e.g., AB-PINACA, AB-CHMINACA). Despite their structural differences, psychoactive synthetic cannabinoids bind with high affinity to CB 1 receptors in the brain and, when tested, have been shown to activate these receptors and to produce a characteristic profile of effects, including suppression of locomotor activity, antinociception, hypothermia, and catalepsy, as well as Δ 9 -tetrahydrocannabinol (THC)-like discriminative stimulus effects in mice. When they have been tested, synthetic cannabinoids are often found to be more efficacious at activation of the CB 1 receptor and more potent in vivo. Further, their chemical alteration by thermolysis during use and their uncertain stability and purity may result in exposure to degradants that differ from the parent compound contained in the original product. Consequently, while their intoxicant effects may be similar to those of THC, use of synthetic cannabinoids may be accompanied by unpredicted, and sometimes harmful, effects.

CUMYL-PICA [1-pentyl- N -(2-phenylpropan-2-yl)-1 H -indole-3-carboxamide] and 5F-CUMYL-PICA [1-(5-fluoropentyl)- N -(2-phenylpropan-2-yl)-1 H -indole-3-carboxamide] are recently identified recreationally used/abused synthetic cannabinoids, but have uncharacterized pharmacokinetic profiles and metabolic processes. This study characterized clearance and metabolism of these compounds by human and rat liver microsomes and hepatocytes, and then compared these parameters with in vivo rat plasma and urine sampling. It also evaluated hypothermia, a characteristic cannabimimetic effect. Incubation of CUMYL-PICA and 5F-CUMYL-PICA with rat and human liver microsomes suggested rapid metabolic clearance, but in vivo metabolism was prolonged, such that parent compounds remained detectable in rat plasma 24 h post-dosing. At 3 mg/kg (intraperitoneally), both compounds produced moderate hypothermic effects. Twenty-eight metabolites were tentatively identified for CUMYL-PICA and, coincidentally, 28 metabolites for 5F-CUMYL-PICA, primarily consisting of phase I oxidative transformations and phase II glucuronidation. The primary metabolic pathways for both compounds resulted in the formation of identical metabolites following terminal hydroxylation or dealkylation of the N -pentyl chain for CUMYL-PICA or of the 5-fluoropentyl chain for 5F-CUMYL-PICA. These data provide evidence that in vivo elimination of CUMYL-PICA, 5F-CUMYL-PICA and other synthetic cannabinoids is delayed compared to in vitro modeling, possibly due to sequestration into adipose tissue. Additionally, the present data underscore the need for careful selection of metabolites as analytical targets to distinguish between closely related synthetic cannabinoids in forensic settings.

Synthetic cannabinoids (SCs) are an emerging class of abused drugs that differ from each other and the phytocannabinoid ∆ 9 -tetrahydrocannabinol (THC) in their safety and cannabinoid-1 receptor (CB 1 R) pharmacology. As efficacy represents a critical parameter to understanding drug action, the present study investigated this metric by assessing in vivo and in vitro actions of THC, two well-characterized SCs (WIN55,212-2 and CP55,940), and three abused SCs (JWH-073, CP47,497, and A-834,735-D) in CB 1 (+/+), (+/-), and (-/-) mice. All drugs produced maximal cannabimimetic in vivo effects (catalepsy, hypothermia, antinociception) in CB 1 (+/+) mice, but these actions were essentially eliminated in CB 1 (-/-) mice, indicating a CB 1 R mechanism of action. CB 1 R efficacy was inferred by comparing potencies between CB 1 (+/+) and (+/-) mice [+/+ ED 50 /+/- ED 50 ], the latter of which has a 50% reduction of CB 1 Rs (i.e., decreased receptor reserve). Notably, CB 1 (+/-) mice displayed profound rightward and downward shifts in the antinociception and hypothermia dose-response curves of low-efficacy compared with high-efficacy cannabinoids. In vitro efficacy, quantified using agonist-stimulated [ 35 S]GTPγS binding in spinal cord tissue, significantly correlated with the relative efficacies of antinociception (r = 0.87) and hypothermia (r = 0.94) in CB 1 (+/-) mice relative to CB 1 (+/+) mice. Conversely, drug potencies for cataleptic effects did not differ between these genotypes and did not correlate with the in vitro efficacy measure. These results suggest that evaluation of antinociception and hypothermia in CB 1 transgenic mice offers a useful in vivo approach to determine CB 1 R selectivity and efficacy of emerging SCs, which shows strong congruence with in vitro efficacy., (Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.)

Anecdotal reports suggest that abused synthetic cannabinoids produce cannabis-like "highs," but some of their effects may also differ from traditional cannabinoids such as Δ(9)-tetrahydrocannabinol (THC). This study examined the binding affinities of first-generation indole-derived synthetic cannabinoids at cannabinoid and noncannabinoid receptors and their effects in a functional observational battery (FOB) and drug discrimination in mice. All seven compounds, except JWH-391, had favorable affinity (≤159 nM) for both cannabinoid receptors. In contrast, binding at noncannabinoid receptors was absent or weak. In the FOB, THC and the six active compounds disrupted behaviors in CNS activation and muscle tone/equilibrium domains. Unlike THC, however, synthetic cannabinoids impaired behavior across a wider dose and domain range, producing autonomic effects and signs of CNS excitability and sensorimotor reactivity. In addition, mice acquired JWH-018 discrimination, and THC and JWH-073 produced full substitution whereas the 5-HT2B antagonist mianserin did not substitute in mice trained to discriminate JWH-018 or THC. Urinary metabolite analysis showed that the compounds were extensively metabolized, with metabolites that could contribute to their in vivo effects. Together, these results show that, while first-generation synthetic cannabinoids shared some effects that were similar to those of THC, they also possessed effects that differed from traditional cannabinoids. The high nanomolar (or absent) affinities of these compounds at receptors for most major neurotransmitters suggests that these divergent effects may be related to the greater potencies and/or efficacies at CB1 receptors; however, action(s) at noncannabinoid receptors yet to be assessed or via different signaling pathways cannot be ruled out., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Cannabis is classified as a schedule I controlled substance by the US Drug Enforcement Agency, meaning that it has no medicinal value. Production is legally restricted to a single supplier at the University of Mississippi, and distribution to researchers is tightly controlled. However, a majority of the population is estimated to believe that cannabis has legitimate medical or recreational value, numerous states have legalized or decriminalized possession to some degree, and the federal government does not strictly enforce its law and is considering rescheduling. The explosive increase in open sale and use of herbal cannabis and its products has occurred with widely variable and in many cases grossly inadequate quality control at all levels-growing, processing, storage, distribution, and use. This paper discusses elements of the analytical and regulatory system that need to be put in place to ensure standardization for the researcher and to reduce the hazards of contamination, overdosing, and underdosing for the end-user.

Alleviation of neuropathic pain by cannabinoids is limited by their central nervous system (CNS) side effects. Indole and indene compounds were engineered for high hCB1R affinity, peripheral selectivity, metabolic stability, and in vivo efficacy. An epithelial cell line assay identified candidates with <1% blood-brain barrier penetration for testing in a rat neuropathy induced by unilateral sciatic nerve entrapment (SNE). The SNE-induced mechanical allodynia was reversibly suppressed, partially or completely, after intraperitoneal or oral administration of several indenes. At doses that relieve neuropathy symptoms, the indenes completely lacked, while the brain-permeant CB1R agonist HU-210 (1) exhibited strong CNS side effects, in catalepsy, hypothermia, and motor incoordination assays. Pharmacokinetic findings of ∼0.001 cerebrospinal fluid:plasma ratio further supported limited CNS penetration. Pretreatment with selective CB1R or CB2R blockers suggested mainly CB1R contribution to an indene's antiallodynic effects. Therefore, this class of CB1R agonists holds promise as a viable treatment for neuropathic pain.

Vaporizing drugs in e-cigarettes is becoming a common method of administration for synthetic cathinones and classical stimulants. Heating during vaporization can expose the user to a cocktail of parent compound and thermolytic degradants, which could lead to different toxicological and pharmacological effects compared to ingesting the parent compound alone via injection or nasal inhalation. This study examined the in vivo toxicological and pharmacological effects of vaporized and injected methamphetamine (METH) and α-pyrrolidinopentiophenone (α-PVP). Male and female ICR mice were administered METH or α-PVP through vapor or i.p. injection. Dose-effect curves were determined for locomotor activity and a functional observational battery (FOB). METH and α-PVP vapor were also evaluated for place preference in male mice. Vapor exposure and injection led to more similarities than differences in toxicological and pharmacological effects. In the FOB, both routes of administration produced typical stimulant effects, and injection also increased some bizarre behaviors (e.g. licking, teeth chattering, darting). Both METH and α-PVP vapor exposure produced conditioned place preference. The two routes of administration had comparable efficacy in locomotor activation, with vapor producing longer lasting effects than injection. Females showed greater METH-induced locomotor activity, and greater incidence of a few somatic signs in the FOB than males. These results explore the toxicology of stimulant vapor inhalation in mice using an e-cigarette device. Despite the current technological and methodological difficulties, studying drug vapor promises to allow determination of toxicological effects of thermolytic products and flavor additives., (Copyright © 2016 Elsevier B.V. All rights reserved.)

CB1 cannabinoid receptors are expressed on vagal afferent fibers and neurons within the solitary tract nucleus (NTS), providing anatomical evidence for their role in arterial baroreflex modulation. To better understand the relationship between the brain renin-angiotensin system (RAS) and endocannabinoid expression within the NTS, we measured dorsal medullary endocannabinoid tissue content and the effects of CB1 receptor blockade at this brain site on cardiac baroreflex sensitivity (BRS) in ASrAOGEN rats with low glial angiotensinogen, normal Sprague-Dawley rats and (mRen2)27 rats with upregulated brain RAS expression. Mass spectrometry revealed higher levels of the endocannabinoid 2-arachidonoylglycerol in (mRen2)27 compared to ASrAOGEN rats (2.70 ± 0.28 vs. 1.17 ± 0.09 ng/mg tissue; P < 0.01), while Sprague-Dawley rats had intermediate content (1.85 ± 0.27 ng/mg tissue). Microinjection of the CB1receptor antagonist SR141716A (36 pmol) into the NTS did not change cardiac BRS in anesthetized Sprague-Dawley rats (1.04 ± 0.05 ms/mmHg baseline vs. 1.17 ± 0.11 ms/mmHg after 10 min). However, SR141716A in (mRen2)27 rats dose-dependently improved BRS in this strain: 0.36 pmol of SR141716A increased BRS from 0.43 ± 0.03 to 0.71 ± 0.04 ms/mmHg (P < 0.001), and 36 pmol of SR141716A increased BRS from 0.47 ± 0.02 to 0.94 ± 0.10 ms/mmHg (P < 0.01). In contrast, 0.36 pmol (1.50 ± 0.12 vs. 0.86 ± 0.08 ms/mmHg; P < 0.05) and 36 pmol (1.38 ± 0.16 vs. 0.46 ± 0.003 ms/mmHg; P < 0.01) of SR141716A significantly reduced BRS in ASrAOGEN rats. These observations reveal differential dose-related effects of the brain endocannabinoid system that influence cardiovagal BRS in animals with genetic alterations in the brain RAS.

Selective antagonism of the orexin 1 (OX1) receptor has been proposed as a potential mechanism for treatment of drug addiction. We have previously reported studies on the structure-activity relationships of tetrahydroisoquinoline-based antagonists. In this report, we elucidated the respective role of the 6- and 7-substitutions by preparation of a series of either 6-substituted tetrahydroisoquinolines (with no 7-substituents) or vice versa. We found that 7-substituted tetrahydroisoquinolines showed potent antagonism of OX1, indicating that the 7-position is important for OX1 antagonism (10 c, Ke = 23.7 nM). While the 6-substituted analogs were generally inactive, several 6-amino compounds bearing ester groups showed reasonable potency (26 a, Ke = 427 nM). Further, we show evidence that suggests several compounds initially displaying insurmountable antagonism at the OX1 receptor are competitive antagonists with slow dissociation rates., (Copyright © 2015 Elsevier Ltd. All rights reserved.)