Search

Aim Proving the Severity of Ethanol Withdrawal Scale (SEWS) significantly reduces Alcohol Withdrawal Syndrome (AWS) treatment Time on Medication Protocol (TOMP). Method Head-to-head Quality Assurance outcome compared separate cohorts of SEWS or Clinical Institute Withdrawal Assessment Alcohol Scale, Revised (CIWA-Ar) data using Student’s t and Wilcoxon tests. Results SEWS-driven treatment (n = 244) reduced TOMP to 2.2 days versus 3.4 days for CIWA-Ar (n = 137); P Conclusion The SEWS is the superior measure of AWS symptoms.

Corticotropin-releasing factor (CRF) is essential for coordinating endocrine and neural responses to stress, frequently facilitated by vasopressin (AVP). Previous work has linked CRF hypersecretion, binding site changes, and dysfunctional serotonergic transmission with anxiety and affective disorders, including clinical depression. Crucially, CRF can alter serotonergic activity. In the dorsal raphé nucleus and serotonin (5-HT) terminal regions, CRF effects can be stimulatory or inhibitory, depending on the dose, site, and receptor type activated. Prior stress alters CRF neurotransmission and CRF-mediated behaviors. Lateral, medial, and ventral subdivisions of the central nucleus of the amygdala (CeA) produce CRF and coordinate stress responsiveness. The purpose of these experiments was to determine the effect of intracerebroventricular (icv) administration of CRF and AVP on extracellular 5-HT as an index of 5-HT release in the CeA, using in vivo microdialysis in freely moving rats and high performance liquid chromatography (HPLC) analysis. We also examined the effect of prior stress (1 h restraint, 24 h prior) on CRF- and AVP-mediated release of 5-HT within the CeA. Our results show that icv CRF infusion in unstressed animals had no effect on 5-HT release in the CeA. Conversely, in rats with prior stress, CRF caused a profound dose-dependent decrease in 5-HT release within the CeA. This effect was long-lasting (240 min) and was mimicked by CRF plus AVP infusion without stress. Thus, prior stress and AVP functionally alter CRF-mediated neurotransmission and sensitize CRF-induced inhibition of 5-HT release, suggesting that this is a potential mechanism underlying stress-induced affective reactivity in humans.

Glial glutamate transporter (GLT-1) modulation in the hippocampus and anterior cingulate cortex (ACC) is critically involved in nociceptive pain. The objective of the study was to investigate the effects of 3-[[(2-methylphenyl) methyl] thio]-6-(2-pyridinyl)-pyridazine (LDN-212320), a GLT-1 activator, against microglial activation induced by complete Freund’s adjuvant (CFA) in a mouse model of inflammatory pain. Furthermore, the effects of LDN-212320 on the protein expression of glial markers, such as ionized calcium-binding adaptor molecule 1 (Iba1), cluster of differentiation molecule 11b (CD11b), mitogen-activated protein kinases (p38), astroglial GLT-1, and connexin 43 (CX43), were measured in the hippocampus and ACC following CFA injection using the Western blot analysis and immunofluorescence assay. The effects of LDN-212320 on the pro-inflammatory cytokine interleukin-1β (IL-1β) in the hippocampus and ACC were also assessed using an enzyme-linked immunosorbent assay. Pretreatment with LDN-212320 (20 mg/kg) significantly reduced the CFA-induced tactile allodynia and thermal hyperalgesia. The anti-hyperalgesic and anti-allodynic effects of LDN-212320 were reversed by the GLT-1 antagonist DHK (10 mg/kg). Pretreatment with LDN-212320 significantly reduced CFA-induced microglial Iba1, CD11b, and p38 expression in the hippocampus and ACC. LDN-212320 markedly modulated astroglial GLT-1, CX43, and, IL-1β expression in the hippocampus and ACC. Overall, these results suggest that LDN-212320 prevents CFA-induced allodynia and hyperalgesia by upregulating astroglial GLT-1 and CX43 expression and decreasing microglial activation in the hippocampus and ACC. Therefore, LDN-212320 could be developed as a novel therapeutic drug candidate for chronic inflammatory pain.

Background: Previously, we reported that the maturity of Psychological Adaptive Mechanism (PAM; alternatively, ego defense mechanism) endorsement, but not depression symptom severity, predicted 5-year survival rates in adult cancer patients and that study controlled for age as a significant variable. In this investigation, we hypothesized that greater PAM maturity would correlate significantly with age and with fewer depression symptoms in a larger sample.Methods: In this cross-section study, adult cancer outpatients (N=293) completed the Defense Style Questionnaire (DSQ), the Beck Depression Inventory (BDI), and provided additional clinical data. Spearman’s correlation and multiple regression modeling provided statistical tests of the study hypotheses.Results: Contrary to our hypothesis, DSQ PAM maturity endorsement did not correlate significantly with increasing age. Greater PAM maturity ratio on the DSQ (pppppConclusion: The results suggest that PAM maturity likely predicts fewer depression symptoms while younger age associates with more depression symptoms in this clinical sample. Centrally, acting cancer medications, such as glucocorticoids, and any history of psychiatric disorder correlated with increased depression symptom frequencies. In this cross-section study, antidepressant medications indicated higher frequencies of depressive symptoms, likely reflecting their use in persons previously diagnosed with depression. Further research should target factors that improve PAM maturity as a potential treatment target, especially in younger age groups.

Early life stress (ELS) is a risk factor for developing a host of psychiatric disorders. Adolescence is a particularly vulnerable period for the onset of these disorders and substance use disorders (SUDs). Here we discuss ELS and its effects in adolescence, especially SUDs, and their correlates with molecular changes to signaling systems in reward and stress neurocircuits. Using a maternal separation (MS) model of neonatal ELS, we studied a range of behaviors that comprise a "drug-seeking" phenotype. We then investigated potential mechanisms underlying the development of this phenotype. Corticotropin releasing factor (CRF) and serotonin (5-HT) are widely believed to be involved in "stress-induced" disorders, including addiction. Here, we show that ELS leads to the development of a drug-seeking phenotype indicative of increased susceptibility to addiction and concomitant sex-dependent upregulation of CRF and 5-HT system components throughout extended brain reward/stress neurocircuits.

Opioids are widely prescribed for pain management, and prescription opioid misuse in adolescents has become a major epidemic in the United States and worldwide. Emerging data indicate that adolescence represents a critical period of brain development, and exposure to opioids during adolescence may increase the risk of addiction in adulthood. There is growing evidence that disruptions in brain glial function may be implicated in numerous chronic neuropathologies. Evidence suggests that glial mechanisms have an important role in the development and maintenance of opioid abuse and the risk for addiction. This review will describe glial and neuroimmune mechanisms involved in opioid use disorders during adolescence, which may increase substance use disorder liability later in life. Moreover, this review will identify some important neuro-glial targets, involved in opioid abuse and addiction, to develop future preventions and treatment strategies.

BACKGROUND Early clinical experience during the COVID-19 pandemic has begun to elucidate that the disease can cause brain function changes that may result in compromised cognition both acutely and during variable recovery periods. Reports on cognitive assessment of patients with COVID-19 are often limited to orientation alone. Further assessment may seem to create an inappropriate burden for patients with acute COVID-19, which is characterized by fatigue and confusion, and may also compromise examiner safety. OBJECTIVE The aims of this study were to assess cognition in patients with COVID-19 as comprehensively as possible in a brief format, while observing safety precautions, and to establish a clear face value of the external validity of the assessment. METHODS We adapted a brief cognitive assessment, previously applied to liver transplant candidates and medical/surgical inpatients, for remote use in patients hospitalized for COVID-19 treatment. Collecting quality assurance data from telephone-administered assessments, this report presents a series of 6 COVID-19 case vignettes to illustrate the use of this 5-minute assessment in the diagnosis and treatment of brain effects. Primary medical teams referred the cases for neuropsychiatric consultation. RESULTS The age of the patients varied over four decades, and none of them were able to engage meaningfully with their surroundings on admission. On follow-up examination 6 to 10 days later, 4 of the 6 patients had recovered working memory, and only 1 had recovered calculation ability. Of the 6 patients, 2 were capable of complex judgment responses, while none of the cases completed frontal executive function testing in the normal range. CONCLUSIONS Cognitive assessment in patients with COVID-19 using this remote examination reveals patterns of cognitive recovery that vary among cases and are far more complex than loss of orientation. In this series, testing of specific temporal, parietal, and frontal lobe functions suggests that calculation ability, judgment, and especially frontal executive functions may characterize the effects of COVID-19 on the brain. Used widely and serially, this examination method can potentially inform our understanding of the effects of COVID-19 on the brain and of healing from the virus.

A high-fat diet (HFD) and loss of endogenous estrogens increases the risk for type 2 diabetes (T2D) and insulin resistance. Although exercise is known to prevent and manage insulin resistance, the cellular mechanisms remain largely unknown, especially in the context of a combined HFD and endogenous estrogen loss via ovariectomy (OVX). This study uses female Wistar rats to assess the effect of diet, endogenous estrogens, an exercise on insulin resistance, serum hormones, hepatic AMPK, hepatic regulators of fat metabolism, and expression of signaling molecules of the brain reward pathway. The combination of the HFD/OVX increased the homeostatic model assessment of insulin resistance (HOMA-IR), the glucose-insulin (G-I) index, and the serum adiponectin and leptin values, and exercise decreased these factors. The combination of the HFD/OVX decreased hepatic pAMPK, and exercise restored hepatic pAMPK, an important regulator of fat and glucose metabolism. Furthermore, consumption of the HFD by rats with intact ovaries (and endogenous estrogens) did not result in these drastic changes compared to intact rats fed a standard diet, suggesting that the presence of estrogens provides whole body benefits. Additionally, the HFD decreased the hepatic protein expression of acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS), two proteins involved in de novo lipid synthesis and increased the hepatic protein expression of lipoprotein lipase (LPL), a protein involved in fat storage. Finally, exercise increased mRNA expression of the dopamine D2 receptor and tyrosine hydroxylase in the dopaminergic neuron cell body region of the ventral tegmental area, which is a key component of the brain reward pathway. Overall, this study demonstrates that exercise prevents insulin resistance even when a HFD is combined with OVX, despite hepatic changes in ACC, FAS, and LPL., Graphical abstract Image 1, Highlights • A HFD/OVX increases T2D risk factors, which are decreased with exercise. • A HFD decreases de novo hepatic lipogenesis and increases hepatic fat storage. • Exercise increases D2 and TH mRNA expression in the ventral tegmental area.

Converging lines of evidence point to a significant role of neuroinflammation in a host of psychiatric conditions, including alcohol use disorder, TBI, and PTSD. A complex interaction of both peripheral and central signaling underlies processes involved in neuroinflammation. Calcineurin is a molecule that sits at the nexus of these processes and has been clearly linked to a number of psychiatric disorders including alcohol use disorder (AUD). Like its role in regulating peripheral immune cells, calcineurin (CN) plays an integral role in processes regulating neuroimmune function and neuroinflammatory processes. Targeting CN or elements of its signaling pathways at critical points may aid in the functional recovery from neuroinflammatory related disorders. In this review we will highlight the role of neuroinflammation and calcineurin signaling in AUD, TBI and stress-induced disorders and discuss recent findings demonstrating a therapeutic effect of immunosuppressant-induced calcineurin inhibition in a pre-clinical model of binge alcohol drinking.

Escalation of anxious behavior while environmentally and socially relevant contextual events amplify the intensity of emotional response produces a testable gradient of anxiety shaped by integrative circuitries. Apprehension of the Stress-Alternatives Model apparatus (SAM) oval open field (OF) is measured by the active latency to escape, and is delayed by unfamiliarity with the passageway. Familiar OF escape is the least anxious behavior along the continuum, which can be reduced by anxiolytics such as icv neuropeptide S (NPS). Social aggression increases anxiousness in the SAM, reducing the number of mice willing to escape by 50%. The apprehension accompanying escape during social aggression is diminished by anxiolytics, such as exercise and corticotropin releasing-factor receptor 1 (CRF1) antagonism, but exacerbated by anxiogenic treatment, like antagonism of α2-adrenoreceptors. What is more, the anxiolytic CRF1 and anxiogenic α2-adrenoreceptor antagonists also modify behavioral phenotypes, with CRF1 antagonism allowing escape by previously submissive animals, and α2-adrenoreceptor antagonism hindering escape in mice that previously engaged in it. Gene expression of NPS and brain-derived neurotrophic factor (BDNF) in the central amygdala (CeA), as well as corticosterone secretion, increased concomitantly with the escalating anxious content of the mouse-specific anxiety continuum. The general trend of CeA NPS and BDNF expression suggested that NPS production was promoted by increasing anxiousness, and that BDNF synthesis was associated with learning about ever-more anxious conditions. The intensity gradient for anxious behavior resulting from varying contextual conditions may yield an improved conceptualization of the complexity of mechanisms producing the natural continuum of human anxious conditions, and potential therapies that arise therefrom.

AIMS: Abstinence among alcohol dependent liver graft recipients is remarkably high. The routine use of anti-immune agents in these patients led to rodent studies showing that immunosuppressants acting through inhibition of calcineurin (CLN) are highly effective in decreasing alcohol consumption. It remained unclear, however, whether the decreased alcohol consumption in rodent models is mediated through peripheral suppression of immune response or centrally through direct inhibition of cyclophilin-CLN in the brain. We tested the hypothesis that direct brain inhibition of CLN with intracerebroventricular (ICV) injections of the immunosuppressant cyclosporine A (CsA) is sufficient to decrease ethanol consumption in a rodent model of binge-like drinking. METHODS: Male C57BL/6NHsd mice were put through a modified ‘drinking in the dark’ (DID) paradigm. Effects of both peripheral (IP) and central (ICV) injections of CsA on ethanol consumption were assessed. RESULTS: Here, as in earlier work, IP CsA administration significantly decreased alcohol consumption. Supporting our hypothesis, central administration of CsA was sufficient to decrease alcohol consumption in a dose-dependent manner. There was no significant effect of CsA on water or sucrose consumption. CONCLUSIONS: These results clearly implicate a CLN-mediated mechanism in brain in the inhibitory effects of CsA on ethanol consumption and provide novel targets for investigation of treatment for Alcohol Use Disorders (AUD). These results also add to the growing body of literature implicating neuroimmune mechanisms in the etiology, pathophysiology and behaviors driving AUD. SHORT SUMMARY: The unusually high abstinence rate and routine use of immunosuppressants in AUD liver graft recipients led us to rodent studies showing that immunosuppressants acting through inhibition of calcineurin (CLN) are highly effective in decreasing drinking. Here we demonstrate that this effect is mediated by brain rather than peripheral immune mechanisms.

Co-occurring schizophrenia spectrum disorder and International Statistical Classification of Diseases, 10th Revision cocaine dependence present a particularly destructive constellation that is often difficult to treat. Both conditions raise dopamine transmission effects in the brain. Traditional neuroleptics block dopamine receptors, whereas aripiprazole modulates dopamine activity as an agonist/antagonist. We tested whether dopamine modulation is superior to dopamine blocking in dual-diagnosis patients.In a randomized, double-blind, comparison design, cocaine-dependent schizophrenic subjects actively using cocaine received either aripiprazole or perphenazine in an 8-week trial. Primary outcome targeted cocaine-free urine sample proportions, whereas cocaine craving scores were a secondary variable.Subjects (N = 44) randomized (n = 22 per group) did not differ at baseline. The proportion of cocaine-free urine samples did not differ by medication group. Contrasting weeks 3 to 5 vs 6 to 8 revealed significant late reductions in craving with aripiprazole. On the respective 5-point subscales, craving intensity decreased by 1.53 ± 0.43 (P0.0005) points, craving frequency by 1.4 ± 0.40 (P0.0004) points, and craving duration by 1.76 ± 0.44 (P0.0001) points.A drug effect of aripiprazole on craving items appeared at week 6 of treatment, on average, and was not seen before that length of drug exposure. The data suggest that dopamine modulation reduces cocaine cravings but requires an acclimation period. To understand the mechanism of action better, a trial of depot aripiprazole may be useful. Clinically, a reduction in craving potentially offers a clearer focus for ongoing behavioral treatment. It may also offer a longer-term treatment effect with respect to the severity of relapse.

Fingerlings of channel catfish Ictalurus punctatus exhibited a significant exposure-dependent decrease in growth (measured by weight gain and increase in total length) and condition factor after 9 weeks of exposure to environmental ammonia. Concentrations of 5-hydroxytryptamine (5-HT) and dopamine in the brain decreased significantly whereas the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT increased significantly in exposure-dependent manners. The brain dopamine concentrations and the 5-HIAA : 5-HT ratio collectively explained 88% of the variation in growth due to ammonia exposure. This study demonstrates the potential to predict ammonia-induced inhibition of growth in channel catfish with physiological changes.

The orexin/hypocretin system interacts with many of the same circuitries contributing to stress-associated disorders like depression and anxiety. These include potentially reciprocal connections with corticotropin releasing factor (CRF) neurons which drive the hypothalamic-pituitary-adrenal (HPA) endocrine response in addition to having an anxiogenic effect in the central amygdala (CeA). Antagonism of the orexin type 1 receptor (Orx1) in the hypothalamus has also been shown to block panic attacks. However, few studies have investigated the effect of orexinergic signaling in the basolateral amygdala (BLA) which is responsible for contextual fear, and modulates the activity of the CeA. To this end, we chronically stressed c57bl/6 mice with social defeat and examined the gene expression of the orexin receptors in the BLA. We found that the transcripts for the Orx1 and Orx2 receptors diverged in the BLA with Orx1 increasing and Orx2 decreasing in animals that were susceptible to the chronic defeat. These changes were not seen in the prelimbic cortex (PrL) which sends efferents to the BLA. We then tried to recapitulate these expression patterns in the BLA using short hairpin interfering sequences delivered by adeno-associated viruses to knock down the orexin receptors. While the Orx1 knockdown did reduce locomotor activity, it did not decrease depressive or anxious behaviors. Knocking down the Orx2 receptors in the BLA increased anxious behavior as measured by reduced social preference and reduced time spent in the center of an open field. Due to the divergent expression patterns of the two receptors in response to chronic stress, orexinergic activity in the BLA may be responsible for bidirectional modulation of anxious behavior. Furthermore, these data raise the possibility that an Orx2 agonist may serve as an effective means to treat anxiety disorders.

The orexin/hypocretin peptide signaling system plays a neuromodulatory role in motivation and stress; two critical components of depression. Although work has been done to identify links between orexin and depression, few specific neuroanatomical associations have been made. These studies have not investigated the relationship between orexin and orexin receptor expression in specific brain regions associated with this disorder. To address this, we examined immobility during the forced swim test (FST) in mice, a commonly used measure of depressive behavior. We analyzed the variation in FST immobility with the distribution of orexin and its receptor mRNA. We found that animals that exhibited more robust depressive behavior had greater or lesser orexin system expression that depended on the limbic brain region analyzed. In the hippocampus there was a negative correlation between orexin expression and FST immobility. Animals that displayed relatively more depressive behavior had lower hippocampal expression of Orexin A (OrxA). In the amygdala, there was a curvilinear relationship between OrxA and FST performance. In addition there was a positive correlation with amygdalar Type I orexin receptor (Orx1) mRNA and depressive behavior. Despite the differences in limbic orexin expression, there was no correlation between immobility and hypothalamic orexin neuron activation as measured by c-Fos. Overall, more severe depressive behavior was associated with reduced hippocampal orexin expression, contrasted with increased orexin plus Orx1 receptor mRNA expression in the amygdala. This divergent pattern between the hippocampus and amygdala mirrors a neurobiological theme seen in depression resulting from reduced hippocampal, but increased amygdalar, size and function.

Cannabis has been cultivated and used by humans for thousands of years. Research for decades was focused on understanding the mechanisms of an illegal/addictive drug. This led to the discovery of the vast endocannabinoid system. Research has now shifted to understanding fundamental biological questions related to one of the most widespread signaling systems in both the brain and the body. Our understanding of cannabinoid signaling has advanced significantly in the last two decades. In this review, we discuss the state of knowledge on mechanisms of Cannabis signaling in the brain and the modulation of key brain neurotransmitter systems involved in both brain reward/addiction and psychiatric disorders. It is highly probable that various cannabinoids will be found to be efficacious in the treatment of a number of psychiatric disorders. However, while there is clearly much potential, marijuana has not been properly vetted by the medical-scientific evaluation process and there are clearly a range of potentially adverse side-effects-including addiction. We are at crossroads for research on endocannabinoid function and therapeutics (including the use of exogenous treatments such as Cannabis). With over 100 cannabinoid constituents, the majority of which have not been studied, there is much Cannabis research yet to be done. With more states legalizing both the medicinal and recreational use of marijuana the rigorous scientific investigation into cannabinoid signaling is imperative.

Cannabis has been cultivated and used by humans for thousands of years. Research for decades was focused on understanding the mechanisms of an illegal/addictive drug. This led to the discovery of the vast endocannabinoid system. Research has now shifted to understanding fundamental biological questions related to one of the most widespread signaling systems in both the brain and the body. Our understanding of cannabinoid signaling has advanced significantly in the last two decades. In this review, we discuss the state of knowledge on mechanisms of Cannabis signaling in the brain and the modulation of key brain neurotransmitter systems involved in both brain reward/addiction and psychiatric disorders. It is highly probable that various cannabinoids will be found to be efficacious in the treatment of a number of psychiatric disorders. However, while there is clearly much potential, marijuana has not been properly vetted by the medical-scientific evaluation process and there are clearly a range of potentially adverse side-effects-including addiction. We are at crossroads for research on endocannabinoid function and therapeutics (including the use of exogenous treatments such as Cannabis). With over 100 cannabinoid constituents, the majority of which have not been studied, there is much Cannabis research yet to be done. With more states legalizing both the medicinal and recreational use of marijuana the rigorous scientific investigation into cannabinoid signaling is imperative.

Due to serious adverse effects and the limited effectiveness of currently available pharmacological therapies for obesity, many research efforts have focused on the development of drugs from natural products. Our previous studies demonstrated that berberine, an alkaloid originally isolated from traditional Chinese herbs, prevented fat accumulation in vitro and in vivo. In this pilot study, obese human subjects (Caucasian) were given 500 mg berberine orally three times a day for twelve weeks. The efficacy and safety of berberine treatment was determined by measurements of body weight, comprehensive metabolic panel, blood lipid and hormone levels, expression levels of inflammatory factors, complete blood count, and electrocardiograph. A Sprague-Dawley rat experiment was also performed to identify the anti-obesity effects of berberine treatment. The results demonstrate that berberine treatment produced a mild weight loss (average 5 lb/subject) in obese human subjects. But more interestingly, the treatment significantly reduced blood lipid levels (23% decrease of triglyceride and 12.2% decrease of cholesterol levels) in human subjects. The lipid-lowering effect of berberine treatment has also been replicated in the rat experiment (34.7% decrease of triglyceride and 9% decrease of cholesterol level). Cortisol, calcitriol, ACTH, TSH, FT4, and SHBG levels were not significantly changed following 12 weeks of berberine treatment. However, there was interestingly, an increase in calcitriol levels seen in all human subjects following berberine treatment (mean 59.5% increase, p=0.11). Blood inflammatory factors (CRP, IL-6, TNFα, COX-2) and erythrocyte sedimentation rate (ESR) were not significantly affected by treatment with berberine. Tests of hematological, cardiovascular, liver, and kidney function following berberine treatment showed no detrimental side effects to this natural compound. Collectively, this study demonstrates that berberine is a potent lipid-lowering compound with a moderate weight loss effect, and may have a possible potential role in osteoporosis treatment/prevention.

DNA photolyases use two noncovalently bound chromophores to catalyze photoreactivation, the blue light-dependent repair of DNA that has been damaged by ultraviolet light. FAD is the catalytic chromophore for all photolyases and is essential for photoreactivation. The identity of the second chromophore is often 7,8-didemethyl-8-hydroxy-5-deazariboflavin (FO). Under standard light conditions, the second chromophore is considered nonessential for photoreactivation because DNA photolyase bound to only FAD is sufficient to catalyze the repair of UV-damaged DNA. phr1 is a photoreactivation-deficient strain of Chlamydomonas. In this work, the PHR1 gene of Chlamydomonas was cloned through molecular mapping and shown to encode a protein similar to known FO synthases. Additional results revealed that the phr1 strain was deficient in an FO-like molecule and that this deficiency, as well as the phr1 photoreactivation deficiency, could be rescued by transformation with DNA constructs containing the PHR1 gene. Furthermore, expression of a PHR1 cDNA in Escherichia coli produced a protein that generated a molecule with characteristics similar to FO. Together, these results indicate that the Chlamydomonas PHR1 gene encodes an FO synthase and that optimal photoreactivation in Chlamydomonas requires FO, a molecule known to serve as a second chromophore for DNA photolyases.

Hyperammonemia, arising from variety of disorders, leads to severe neurological dysfunction. The mechanisms of ammonia toxicity in brain are not completely understood. This study investigated the effects of ammonia on monoaminergic systems in brains of fathead minnows (Pimephales promelas). Fish serve as a good model system to investigate hyperammonemic effects on brain function since no liver manipulations are necessary to increase endogenous ammonia concentrations. Using high performance liquid chromatography with electrochemical detection, monoamines and some associated metabolites were measured from whole brain homogenate. Adult males were exposed for 48 h to six different concentrations of ammonia (0.01-2.36 mg/l unionized) which bracketed the 96-h LC(50) for this species. Ammonia concentration-dependent decreases were found for the catecholamines (norepinephrine and dopamine) and the indoleamine serotonin (5-HT). After an initial increase in the 5-HT precursor 5-hydroxytryptophan it too decreased with increasing ammonia concentrations. There were also significant increases in the 5-HIAA/5-HT and DOPAC/DA ratios, often used as measures of turnover. There were no changes in epinephrine (Epi) or monoamine catabolites (DOPAC, 5-HIAA) at any ammonia concentrations tested. Results suggest that ammonia causes decreased synthesis while also causing increased release and degradation. Increased release may underlie behavioral reactions to ammonia exposure in fish. This study adds weight to a growing body of evidence demonstrating that ammonia leads to dysfunctional monoaminergic systems in brain which may underlie neurological symptoms associated with human disorders such as hepatic encephalopathy.

Plasma catecholamines in newborn rats (0-2 hr old) were analyzed following vaginal birth, cesarean section with simulated labor contractions, or cesarean section without labor contractions. Upon delivery, pups were exposed to key elements of the rat's natural birth process, that is, umbilical cord occlusion, tactile stimulation, and cooling. Only pups exposed to actual or simulated labor showed an immediate rise in norepinephrine and epinephrine. Initial postpartum respiratory frequencies were higher in vaginal than in cesarean delivered pups and, in all groups, inversely correlated with catecholamine titers, suggesting respiratory distress or transient tachypnea at lower catecholamine levels. These findings establish a rat model for analyzing effects of labor on neonatal adaptive response during the transition from prenatal to postnatal life.

Central serotonin (5-HT) metabolism during embryogenesis and a 3-day post-hatching period was analyzed using high performance liquid chromatography in the directly developing frog, Eleutherodactylus coqui. This anuran bypasses the free-swimming larval stage and embryos hatch as miniature frogs in the adult phenotype. During embryogenesis and for a short time immediately after hatching, male E. coqui provide paternal care by brooding and guarding eggs/embryos to prevent desiccation and predation. Serotonin and its catabolite, 5-HIAA, were measured from whole brain during embryogenesis and at 3 days post-hatch to identify critical periods in 5-HT development and to determine the relationship between 5-HT and life history events such as hatching and frog dispersal from the nest site. Serotonergic activity was highest during the early-mid embryonic stages as indicated by the ratio of 5-HIAA/5-HT, a general indicator of turnover and metabolism. There were significant increases in tissue concentrations of 5-HT during the latest or terminal embryonic stage, just prior to hatching, and also at 3 days post-hatch, shortly before neonates disperse into the rainforest. These two increases probably represent different functional requirements during development. The first may occur as a result of the surge of development in the 5-HT system during late embryogenesis that occurs in E. coqui and the second may be from the increase demand in sensory and motor neural development required before dispersal from the nest site.

Serotonin is widely believed to exert inhibitory control over aggressive behavior and intent. In addition, a number of studies of fish, reptiles, and mammals, including the lizard Anolis carolinensis, have demonstrated that serotonergic activity is stimulated by aggressive social interaction in both dominant and subordinate males. As serotonergic activity does not appear to inhibit agonistic behavior during combative social interaction, we investigated the possibility that the negative correlation between serotonergic activity and aggression exists before aggressive behavior begins. To do this, putatively dominant and more aggressive males were determined by their speed overcoming stress (latency to feeding after capture) and their celerity to court females. Serotonergic activities before aggression are differentiated by social rank in a region-specific manner. Among aggressive males baseline serotonergic activity is lower in the septum, nucleus accumbens, striatum, medial amygdala, anterior hypothalamus, raphe, and locus ceruleus but not in the hippocampus, lateral amygdala, preoptic area, substantia nigra, or ventral tegmental area. However, in regions such as the nucleus accumbens, where low serotonergic activity may help promote aggression, agonistic behavior also stimulates the greatest rise in serotonergic activity among the most aggressive males, most likely as a result of the stress associated with social interaction.

Adenosine is a ubiquitous neuromodulator that increases sleep, inhibits seizures, and promotes neuroprotection. Many of these effects are mediated by A1 receptors, but A1 receptors are expressed in most brain regions, and distinguishing the precise site of action of adenosine is challenging. To test the role of adenosine in different hippocampal regions, we have used theCre-loxPsystem and an adeno-associated viral (AAV) vector to focally delete endogenous adenosine A1 receptors in the hippocampus. Microinjection of an AAV vector containing the gene for Cre recombinase induced intense, focal, neuron-specific recombination in reporter mice. In a separate line of mice with loxP sites flanking the major coding exon for the adenosine A1 receptor, this AAV-Cre markedly reduced A1 receptor mRNA and focally abolished the postsynaptic response to adenosine without any change in basic electrophysiologic properties. Adenosine inhibits signaling between CA3 and CA1 neurons, but it is unclear from pharmacologic studies whether this response is caused by presynaptic or postsynaptic effects. Deletion of A1 receptors from CA3 neurons abolished this response to adenosine, but deletion of A1 receptors from CA1 neurons had no effect, demonstrating a presynaptic site of action. This transduction knock-out technique holds enormous potential for dissecting the functions of different CNS pathways.

Central serotonin (5-HT) is activated during stressful situations and aggressive interactions in a number of species. Glucocorticoids secreted peripherally during stressful events feed back on central systems and may affect 5-HT mediation of stress-induced behavioral events. To test the neuromodulatory effect of stress hormone secretion, serotonin overflow was measured from the hippocampus of the lizard Anolis carolinensis. Microdialysis was used to collect repeated samples from anesthetized lizards, with perfusate measured by HPLC with electrochemical analysis. Following initially high levels of 5-HT, concentrations stabilized to basal levels after approximately 2 h. Intracortical infusion of 200 ng/ml corticosterone evoked transient increases in 5-HT release of approximately 400%. The effect of corticosterone on 5-HT overflow appears to be dose dependent as 20 ng/ml stimulated an increase of 200%, whereas 2 ng/ml stimulated a 50% increase. Administration of 0.1 and 1 ng/ml GABA via the dialysis probe significantly inhibited 5-HT overflow by 20 and 40%, respectively. The duration of GABA inhibition is greater than the stimulatory response for glucocorticoids. Short-lived glucocorticoid stimulation of 5-HT release suggests a possible mechanism for endocrine mediation of continuously changing social behavioral events.

Dominant and subordinate males respond differently to the stress of social interaction. After an hour of social interaction, subordinate male Anolis carolinensis have elevated serotonergic activity in hippocampus, but dominant males do not. In other species, and using other stressors, the activation of hippocampal serotonergic activity is much more rapid than one hour. To elucidate early stress responsiveness, adult male A. carolinensis were divided into four groups: isolated controls, and pairs of males sampled after 10, 20 or 40 minutes of aggressive interaction. Development of dominant-subordinate relationships was determined by behavior and by the celerity of eyespot darkening. Serotonergic activity in the hippocampus, nucleus accumbens and amygdala was elevated rapidly and equally in both dominant and subordinate males, as were plasma corticosterone concentrations. Serotonergic activity remained elevated through 40 minutes in hippocampus and nucleus accumbens. Only subordinate males had elevated corticosterone levels at 40 minutes. Social status does not impede socially induced stress responses. Rather, rapid regulation of serotonergic stress responses appears to be a mediating factor in determining both behavioral output and social status. Temporal expressions of monoaminergic and endocrine stress responses are distinctive between males of dominant and subordinate social status. Such temporal patterns of transmitter and glucocorticoid activity may reflect neurocircuitry adaptations that result in behavior modified to fit social status.

(1) Disturbances of mesolimbic and mesocortical dopamine (DA) function have been implicated in the pathophysiology of several psychiatric disorders, including major depressive disorder. (2) Utilizing the learned helplessness (LH) animal model of clinical depression and quantitative autoradiography, the authors studied the densities of D1 and dopamine-2-like receptors (D2-like receptors) in medial prefrontal cortex, septum, nucleus accumbens and caudate nucleus in rats that received inescapable stress and were subsequently tested for LH behavior. (3) Dopamine-1 receptor (D1 receptor) densities were significantly higher in the core and shell of the nucleus accumbens and in the medial caudate nucleus of rats that did not become helpless after stress, compared to rats that developed LH. (4) Densities of D2-like receptors were significantly lower in the core of the nucleus accumbens in both the LH and the nonhelpless (NH) rats compared to controls. Densities of D2-like receptors were also lower in the medial and lateral caudate nuclei in LH rats compared to the other groups. (5) Increased D1 receptor densities in NH rats in the nucleus accumbens may be associated with an adaptive or protective role of this brain region in the prevention of escape deficits after exposure to inescapable stress. (6) Decreased D2-like receptor densities in the caudate nucleus in helpless rats may reflect a motor deficit associated with LH behavior, while decreases of D2-like receptor densities in the core of the nucleus accumbens may reflect a generalized effect of exposure to inescapable stress. (7) This study highlights the importance of the mesolimbic/nigrostriatal dopaminergic systems in mediating behavioral responses to inescapable stress.

GABA is involved in both clinical depression and in animal models of depression; however, the roles of GABA(A) and GABA(B) receptors in specific brain regions are not clear. Changes in densities of both GABA(A) and GABA(B) receptors have been reported with the learned helplessness animal model of depression and with chronic antidepressant drug treatment. However, some of these findings are discrepant. Thus, we used quantitative autoradiography to study the GABA(A) and GABA(B) receptors in learned helplessness and we used an experimental paradigm that allows non-specific effects of stress to be differentiated from learned helplessness. Densities of GABA binding were measured in prefrontal cortex, septum, hippocampus, hypothalamus and amygdala. In the septum, learned helpless rats had increased densities of GABA(A) receptors and rats that did not become helpless after inescapable stress had decreased GABA(B) receptor densities. No significant group differences of GABA(A) or GABA(B) receptor densities were observed in any other brain region studied. These results suggest a unique role for the septum in modulating GABA in the learned helplessness animal model of depression.

Fingerlings of channel catfish Ictalurus punctatus exhibited a significant exposure-dependent decrease in growth (measured by weight gain and increase in total length) and condition factor after 9 weeks of exposure to environmental ammonia. Concentrations of 5-hydroxytryptamine (5-HT) and dopamine in the brain decreased significantly whereas the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT increased significantly in exposure-dependent manners. The brain dopamine concentrations and the 5-HIAA : 5-HT ratio collectively explained 88% of the variation in growth due to ammonia exposure. This study demonstrates the potential to predict ammonia-induced inhibition of growth in channel catfish with physiological changes.

Learned helplessness is a behavioral deficit that can be induced by exposure to inescapable stress. Previous studies have implicated the lateral septum in mediating this phenomenon, and in this brain region, serotonin plays an important role in the development, maintenance, prevention, and reversal of learned helplessness behavior. Using the technique of in vivo microdialysis, we measured the efflux of serotonin (5-HT), dopamine (DA), and their respective metabolites, 5-hydroxyindoleacetic acid (5-HIAA) and 3, 4-dihydroxyphenylacetic acid (DOPAC), from the lateral septum of rats that either developed or did not develop learned helplessness. During the microdialysis session all rats were subjected to restraint stress. Control groups included naive, home cage rats as well as tested control rats that were subjected to the identical handling, restraint, and shuttlebox testing as the rats that received inescapable shock. Overall, levels of 5-HIAA were significantly higher in non-helpless rats. There were no significant effects of restraint or differences in levels of 5-HT, DA, or DOPAC. We propose that this increase in 5-HIAA is indicative of an overall increase in serotonin metabolism in the lateral septum of rats that do not become helpless after inescapable stress. This increased serotonin metabolism in the lateral septum may protect the animal from adverse behavioral consequences of inescapable stress. J. Neurosci. Res. 61:101-106, 2000. Published 2000 Wiley-Liss, Inc.

Corticotropin releasing factor (CRF) is a primary mediator of endocrine, autonomic and behavioral stress responses. Studies in both humans and animal models have implicated CRF in a wide-variety of psychiatric conditions including anxiety disorders such as post-traumatic stress disorder (PTSD), depression, sleep disorders and addiction among others. The central nucleus of the amygdala (CeA), a key limbic structure with one of the highest concentrations of CRF-producing cells outside of the hypothalamus, has been implicated in anxiety-like behavior and a number of stress-induced disorders. This study investigated the specific role of CRF in the CeA on both endocrine and behavioral responses to stress. We used RNA Interference (RNAi) techniques to locally and specifically knockdown CRF expression in CeA. Behavior was assessed using the elevated plus maze (EPM) and open field test (OF). Knocking down CRF expression in the CeA had no significant effect on measures of anxiety-like behavior in these tests. However, it did have an effect on grooming behavior, a CRF-induced behavior. Prior exposure to a stressor sensitized an amygdalar CRF effect on stress-induced HPA activation. In these stress-challenged animals silencing CRF in the CeA significantly attenuated corticosterone responses to a subsequent behavioral stressor. Thus, it appears that while CRF projecting from the CeA does not play a significant role in the expression stress-induced anxiety-like behaviors on the EPM and OF it does play a critical role in stress-induced HPA activation.

The corticotropin releasing factor (CRF) system coordinates a wide range of stress responses and has been implicated in the etiology of a number of clinical disorders. It is made up of a complex array of interactive peptides that interact with many other neurotransmitter and neuromodulatory systems. Dysregulation of CRF system signaling may be a common molecular pathway for the myriad "stress-related" disorders. Understanding the signaling and circuitry affected by this system is essential to understanding these psychiatric disorders. The extremely wide range of behaviors and physiological processes mediated by this system and the complexity of its signaling make this a difficult task-especially to successfully target it for pharmacotherapy. In this review, we describe the molecular signaling of the CRF system and its interaction with other key neurotransmitter systems. Its role in a range of psychiatric disorders and potential as a target for therapeutic intervention will also be discussed.

The corticotropin releasing factor (CRF) system coordinates a wide range of stress responses and has been implicated in the etiology of a number of clinical disorders. It is made up of a complex array of interactive peptides that interact with many other neurotransmitter and neuromodulatory systems. Dysregulation of CRF system signaling may be a common molecular pathway for the myriad “stress-related” disorders. Understanding the signaling and circuitry affected by this system is essential to understanding these psychiatric disorders. The extremely wide range of behaviors and physiological processes mediated by this system and the complexity of its signaling make this a difficult task—especially to successfully target it for pharmacotherapy. In this review, we describe the molecular signaling of the CRF system and its interaction with other key neurotransmitter systems. Its role in a range of psychiatric disorders and potential as a target for therapeutic intervention will also be discussed.

Stable social relationships are rearranged over time as resources such as favored territorial positions change. We test the hypotheses that social rank relationships are relatively stable, and although social signals influence aggression and rank, they are not as important as memory of an opponent. In addition, we hypothesize that eyespots, aggression and corticosterone influence serotonin and N-methyl-D: -aspartate (NMDA) systems in limbic structures involved in learning and memory. In stable adult dominant-subordinate relationships in the lizard Anolis carolinensis, social rank can be reversed by pharmacological elevation of limbic serotonergic activity. Any pair of specific experiences: behaving aggressively, viewing aggression or perceiving sign stimuli indicative of dominant rank also elevate serotonergic activity. Differences in the extent of serotonergic activation may be a discriminating and consolidating factor in attaining superior rank. For instance, socially aggressive encounters lead to increases in plasma corticosterone that stimulate both serotonergic activity and expression of the NMDA receptor subunit 2B (NR(2B)) within the CA(3) region of the lizard hippocampus. Integration of these systems will regulate opponent recognition and memory, motivation to attack or retreat, and behavioral and physiological reactions to stressful social interactions. Contextually appropriate social responses provide a modifiable basis for coping with the flexibility of social relationships.

Corticotropin-releasing factor (CRF) coordinates neuroendocrine responses to stressful stimuli; one mechanism through which CRF may modulate hypothalamic-pituitary-adrenal axis activity is via actions on neuromodulatory systems such as serotonergic systems. Recent electrophysiological studies and the distribution of CRF receptors within midbrain and pontine raphe nuclei suggest that stress and CRF may have actions on topographically organized subpopulations of serotonergic neurones. We compared the effects of vehicle or intracerebroventricular r/hCRF injections (0, 0.1, 1 or 10 micro g) in rats previously maintained in home cages or restrained for 1 h, 24 h before injection, on monoamine and monoamine metabolite tissue concentrations in the dorsal (lateral wings, rostral midline, caudal midline), median (rostral, caudal) and interfascicular raphe subdivisions of the midbrain and pontine raphe nuclei, using brain microdissection and high-performance liquid chromatography with electrochemical detection. At the lowest dose studied (0.1 micro g), CRF infusions in previously stressed rats decreased 5-hydroxytryptophan (5-HTP) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations only within the rostral median raphe nucleus. At higher doses, CRF infusions in previously stressed rats increased tissue concentrations of 5-HTP, serotonin (5-HT), or the serotonin metabolite, 5-HIAA, within rostral (but not caudal) regions of the median and dorsal raphe nuclei. By contrast, restraint stress alone had no effect on tissue concentrations of 5-HTP, 5-HT or 5-HIAA measured 24 h later in any subdivision, while CRF injections in rats not previously exposed to restraint stress, with few exceptions, also had no effect. These results suggest that the effects of CRF on serotonergic function are context-dependent, dose-dependent, and regionally specific within subdivisions of the brainstem raphe nuclei.

(1) Disturbances of mesolimbic and mesocortical dopamine (DA) function have been implicated in the pathophysiology of several psychiatric disorders, including major depressive disorder. (2) Utilizing the learned helplessness (LH) animal model of clinical depression and quantitative autoradiography, the authors studied the densities of D1 and dopamine-2-like receptors (D2-like receptors) in medial prefrontal cortex, septum, nucleus accumbens and caudate nucleus in rats that received inescapable stress and were subsequently tested for LH behavior. (3) Dopamine-1 receptor (D1 receptor) densities were significantly higher in the core and shell of the nucleus accumbens and in the medial caudate nucleus of rats that did not become helpless after stress, compared to rats that developed LH. (4) Densities of D2-like receptors were significantly lower in the core of the nucleus accumbens in both the LH and the nonhelpless (NH) rats compared to controls. Densities of D2-like receptors were also lower in the medial and lateral caudate nuclei in LH rats compared to the other groups. (5) Increased D1 receptor densities in NH rats in the nucleus accumbens may be associated with an adaptive or protective role of this brain region in the prevention of escape deficits after exposure to inescapable stress. (6) Decreased D2-like receptor densities in the caudate nucleus in helpless rats may reflect a motor deficit associated with LH behavior, while decreases of D2-like receptor densities in the core of the nucleus accumbens may reflect a generalized effect of exposure to inescapable stress. (7) This study highlights the importance of the mesolimbic/nigrostriatal dopaminergic systems in mediating behavioral responses to inescapable stress.

A social sign stimulus that is sympathetically induced affects aggressive approaches and influences serotonergic, dopaminergic and noradrenergic activity in the brainstem nuclei of Anolis carolinensis. Darkening of postorbital skin via sympathetic activation of adrenal catecholamines and β2-adrenergic receptors provides a visual signal that forms more rapidly in dominant than subordinate males during social interactions. This signal limits aggressive interactions. Males were painted postorbitally with green or black paint and then exposed to a mirror. Aggressive approaches to the mirror were inhibited in males viewing a reflection with darkened eyespots, and increased in males viewing a reflection without eyespots (hidden). Noradrenergic turnover in the raphe and locus ceruleus were greatest in test subjects that viewed a reflection with eyespots hidden by green paint. Perception of darkened eyespots stimulated greater serotonergic turnover in raphe, locus ceruleus and substantia nigra/ventral tegmental area (SN/VTA). Dopaminergic turnover was higher in the raphe and SN/VTA of Anolis that viewed a reflection with darkened eyespots. However, these animals had lower dopamine turnover in the locus ceruleus than isolated and hidden eyespot groups. Of the possible roles of perikarya on central function and behavior, our results suggest feedback, cross-nuclear regulation, and some independence of function between nuclei and the forebrain terminal fields. Decreased serotonergic activity corresponds with increased aggression only in the raphe, suggesting that the raphe nuclei might be important for this behavioral trait. Increased serotonergic, noradrenergic and dopaminergic activities in SN/VTA in Anolis that view a reflected opponent with dark eyespots suggests that the SN/VTA might be directly involved in recognition of this social sign stimulus and the resulting inhibition of aggression.

Darkening of postorbital skin in Anolis carolinensis occurs during stressful situations and is stimulated by sympathetic activation of β2-adrenergic receptors via adrenal catecholamines. This eyespot forms more rapidly in dominant males during social interaction. Eyespot darkening (green to black) appears to function as a social signal communicating sympathetic activation and limiting aggressive interaction. To assess the value of the eyespot as a social signal, males were painted postorbitally with green, black, or red paint. Each male was exposed to a mirror following acclimation to the cage. The total number of aggressive displays toward the mirror image was greatest when eyespots were masked by green paint. In contrast, black or red artificial eyespots, regardless of size, inhibited biting behavior toward the mirror image. The most aggressive males, those who saw a reflected opponent with no eyespot (hidden with green paint), had significantly higher levels of all plasma catecholamines. These results suggest that A. carolinensis use information from the eyespot to assess their opponent's readiness to fight and thereby determine whether to be aggressive. Darkened eyespots are capable of inhibiting aggression, whereas aggressive displays from an opponent in the mirror without darkened eyespots do not. Darkened eyespots reflect rapid changes in plasma NE, DA, and Epi that may signal dominant social status.

During the breeding season different social classes of field-active lizards, Sceloporus jarrovi, exhibit regionally specific changes in central monoaminergic activation. Changes in serotonergic content and turnover between lizards from different social classes are seen in forebrain structures (telencephalon and diencephalon) and reflect events associated with reproductive behaviors, stress and aggression. Males without territories (satellite males) exhibit higher forebrain serotonin (5-HT) system activation compared to territorial males and adult females. This serotonergic activation includes increased 5-hydroxyindoleacetic acid (5-HIAA) and 5-HIAA/5-HT ratio, suggesting increased release and catabolism. Satellite males also exhibit higher 5-HIAA/5-HT ratios (serotonergic turnover) compared to territorial males following agonistic interactions. Territorial males, immediately following aggressive defense of territories against intruder males, exhibit increased 5-hydroxytryptophan (5-HTP) levels, higher 5-HIAA levels and 5-HIAA/5-HT ratio, higher epinephrine levels, greater MHPG/NE, more DOPAC and larger DOPAC/DA ratio compared to territorial males that did not have an aggressive encounter. These differences suggest activation of 5-HT, norepinephrine (NE), and dopamine (DA) systems by the synthesis and release of more 5-HT and the release of more NE and DA during aggressive defense of territory. The highest activity of serotonergic systems is exhibited by satellite males compared to territorial males, perhaps reflecting stress in subordinate animals from social and ecological sources.