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Atypical chemokine receptor CXCR7 (ACKR3) functions as a scavenger receptor for chemokine CXCL12, a molecule that promotes multiple steps in tumor growth and metastasis in breast cancer and multiple other malignancies. Although normal vascular endothelium expresses low levels of CXCR7, marked upregulation of CXCR7 occurs in tumor vasculature in breast cancer and other tumors. To investigate effects of endothelial CXCR7 in breast cancer, we conditionally deleted this receptor from vascular endothelium of adult mice, generating CXCR7(ΔEND/ΔEND) animals. CXCR7(ΔEND/ΔEND) mice appeared phenotypically normal, although these animals exhibited a modest 35±3% increase in plasma CXCL12 as compared with control. Using two different syngeneic, orthotopic tumor implant models of breast cancer, we discovered that CXCR7(ΔEND/ΔEND) mice had significantly greater local recurrence of cancer following resection, elevated numbers of circulating tumor cells and more spontaneous metastases. CXCR7(ΔEND/ΔEND) mice also showed greater experimental metastases following intracardiac injection of cancer cells. These results establish that endothelial CXCR7 limits breast cancer metastasis at multiple steps in the metastatic cascade, advancing understanding of CXCL12 pathways in tumor environments and informing ongoing drug development targeting CXCR7 in cancer.

Chemokines critically regulate chemotaxis in normal and pathologic states, but there is limited understanding of how multicellular interactions generate gradients needed for cell migration. Previous studies of chemotaxis of CXCR4+ cells toward chemokine CXCL12 suggest the requirement of cells expressing scavenger receptor CXCR7 in a source-sink system. We leveraged an established microfluidic device to discover that chemotaxis of CXCR4 cells toward distinct isoforms of CXCL12 required CXCR7 scavenging only under conditions with higher than optimal levels of CXCL12. Chemotaxis toward CXCL12-β and -γ isoforms, which have greater binding to extracellular molecules and have been largely overlooked, was less dependent on CXCR7 than the more commonly studied CXCL12-α. Chemotaxis of CXCR4+ cells toward even low levels of CXCL12-γ and CXCL12-β still occurred during treatment with a FDA-approved inhibitor of CXCR4. We also detected CXCL12-γ only in breast cancers from patients with advanced disease. Physiological gradient formation within the device facilitated interrogation of key differences in chemotaxis among CXCL12 isoforms and suggests CXCL12-γ as a biomarker for metastatic cancer.

Patients often present to the emergency department with loss of consciousness. The differential diagnosis of such condition may be difficult because of limited clinical information. The authors present a case of subarachnoid haemorrhage (SAH) with initial electrocardiographic (ECG) finding mimicking ST-segment elevation myocardial infarction (STEMI), which was confirmed to resolve in a follow-up study. Accurate and timely diagnosis of SAH-related ST-segment elevation was important, as the therapeutic strategy for SAH is completely different from that for STEMI. If the clinicians do not have other tools for diagnosis, the follow-up ECG may help us make a most possible diagnosis.

A series of 3-(phenoxy-phenyl-methyl)-pyrrolidine analogues were discovered to be potent and balanced norepinephrine (NE) and serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors. Several of these compounds were identified to have suitable in vitro pharmacokinetic properties for an orally dosed and CNS-targeted drug. Compound 39b, in particular, was identified as a potent NET and SERT reuptake inhibitor (NSRI) with minimal off-target activity and demonstrated robust efficacy in the spinal nerve ligation model of pain behavior.

By using a combination of genetic, pharmacological, and anatomical approaches, we show that the melanocortin 4 receptor (MC4R), implicated in the control of food intake and energy expenditure, also modulates erectile function and sexual behavior. Evidence supporting this notion is based on several findings: ( i ) a highly selective non-peptide MC4R agonist augments erectile activity initiated by electrical stimulation of the cavernous nerve in wild-type but not Mc4r -null mice; ( ii ) copulatory behavior is enhanced by administration of a selective MC4R agonist and is diminished in mice lacking Mc4r; ( iii ) reverse transcription (RT)-PCR and non-PCR based methods demonstrate MC4R expression in rat and human penis, and rat spinal cord, hypothalamus, brainstem, pelvic ganglion (major autonomic relay center to the penis), but not in rat primary corpus smooth muscle cavernosum cells; and ( iv ) in situ hybridization of glans tissue from the human and rat penis reveal MC4R expression in nerve fibers and mechanoreceptors in the glans of the penis. Collectively, these data implicate the MC4R in the modulation of penile erectile function and provide evidence that MC4R-mediated proerectile responses may be activated through neuronal circuitry in spinal cord erectile centers and somatosensory afferent nerve terminals of the penis. Our results provide a basis for the existence of MC4R-controlled neuronal pathways that control sexual function.

Eighteen of 56 (32.1%) wild Rana limnocharis from central and south Taiwan were found to contain plerocercoids of Spirometra erinaceieuropaei. This is the first report of S. erinaceieuropaei infections in frogs in Taiwan, with the plerocercoids being recovered from the thigh and back muscles or under the skin. Other species of frogs examined, including nine wild R. latouchii, one wild Buergeria robustus and 110 cultured R. rugulosa were free of infection. The plerocercoids were orally inoculated into four cats; three of which were each given a single plerocercoid and one a dose of three plerocercoids. Daily faecal examination showed that two cats started shedding eggs of S. erinaceieuropaei on day 8 postinfection (PI) and the other two on day 10 PI. The highest eggs per gram and eggs per day for a single worm was found to be 428,000 and 14,416,000 respectively. Only the cat inoculated with three plerocercoids shed proglottids in its faeces during the 2 month observation period.

Dihydropyrimidinones, such as 1, represent a novel class of α1a adrenoceptor antagonists with potential for the treatment of benign prostatic hyperplasia (BPH) (see part 1 of this series). Analysis of the metabolites of 1 revealed that 4-methoxycarbonyl-4-phenylpiperidine is formed as the major metabolite and is an agonist at the μ-opioid receptor. To circumvent any potential liability resulting from the metabolite, we decided to identify alternate templates devoid of agonist activity at the μ-opioid receptor to replace the 4-methoxycarbonyl-4-phenylpiperidine moiety. The present study describes the synthesis and SAR of dihydropyrimidinones linked to substituted 4-phenylpiperazine containing side chains. Compound (+)-38 was identified as a lead compound with a binding and functional profile comparable to that of 1. The putative metabolite 2-carboxamidophenylpiperazine has negligible affinity for the μ-opioid receptor.

Cholescintigraphy was performed after pharmacological manipulation in 60 patients with a clinical suspicion of acute cholecystitis and non-visualization of the gallbladder 1 h after 99Tcm-DISIDA cholescintigraphy. Thirty patients received an intravenous (i.v.) injection of morphine sulphate (group I) and the other 30 patients an i.v. injection of CCK (group II). The sensitivity, specificity, positive predictive value and negative predictive value were 94, 100, 100 and 93% in group I and 100, 84, 79 and 100% in group II, respectively. There was a significant difference between groups (P < 0.05). In conclusion, morphine-augmented cholescintigraphy could supply more reliable diagnostic information and is less time-consuming in patients with a clinical suspicion of acute cholecystitis.

We have raised antibodies and developed one-step enzyme-linked immunosorbent assays (ELISA) for the diuretics ethacrynic acid and bumetanide as part of a panel of pre- and post-race tests for high potency drugs in racing horses. These ELISA tests are rapid (completed within one hour), sensitive, and can be read by eye. The ELISA detects ethacrynic acid at a drug concentration for half-maximal inhibition (I-50) of about 2.5 ng/mL for the parent drug. After dosing horses intravenously with 5 mg ethacrynic acid per horse, the parent drug or its metabolites are detectable in urine for at least 8 hours. The bumetanide ELISA has an I-50 for the parent drug of about 2.0 ng/mL and will detect bumetanide or its metabolites for about 8 hours in urine after intravenous administration of a 1.7-mg dose per horse. Both antibodies are relatively specific for each drug and do not cross-react with other commonly used diuretics or other acidic compounds often found in post-race equine urine samples. Ethacrynic acid and bumetanide are potent diuretics suspected of being illegally substituted for furosemide in certain racing jurisdictions. Development of these rapid, sensitive, and simple tests for these agents will allow more effective pre- and post-race control of the use of these agents in racing horses. Both tests have recently uncovered several "positives" for these medications in a midwestern racing jurisdiction.

A series of trisubstituted triazolinones with a [2′-(N-acylsulfamoy)biphenyl-4-yl]methyl side chain at N4 has been prepared. The inhibition of AII pressor responses by these potent AT1-selective AII antagonists indicated some of them to be superior in vivo to their tetrazole counterparts. At 1 mg/kg, 3d (L-159,913) was effective orally with > 4 h duration in dogs and had significant efficacy with > 10 h duration i.v. in chimpanzees.

There remains an urgent need for therapeutic agents that provide improved symptomatic treatment and attenuate disease progression in patients with Alzheimer's disease (AD). 5-HT(4) receptors are widely expressed in those CNS areas which receive substantial cholinergic input and are involved in cognition. The ability of 5-HT(4) receptor agonists to increase acetylcholine (ACh) release and reduce cognitive impairment in both animals and humans has been demonstrated. In addition, 5-HT(4) receptor agonist modulation of levels of the amyloid precursor protein (APP) derived peptides, soluble amyloid precursor protein (sAPPα) and amyloid beta protein (Aβ) in the CNS has been reported. In this study, the preclinical properties of three structurally-distinct 5-HT(4) receptor selective agonists, PRX-03140, velusetrag and TD-8954, were studied to assess their potential for symptomatic and disease-modifying benefit in the treatment of AD. All three compounds exhibited high affinity for the rat 5-HT(4) receptor but could be discriminated on the basis of their agonist activity. In cAMP accumulation and sAPPα secretion assays using recombinant HEK293f-5-HT(4(d))-APP(695) cells, velusetrag and TD-8954 were potent, full agonists, relative to 5-HT, whereas PRX-03140 was a partial agonist (intrinsic activity 18%, relative to 5-HT). In a guinea pig colon isolated tissue preparation, TD-8954 exhibited lower intrinsic activity than velusetrag, and PRX-03140 had negligible agonist activity. In the rat Morris water maze (MWM) cognition test, velusetrag and TD-8954 (0.1 mg/kg), but not PRX-03140 (0.03-1 mg/kg), significantly reversed the scopolamine-induced spatial learning deficit via activation of 5-HT(4) receptors. Coadministration of subefficacious doses of the acetylcholinesterase inhibitor (AChEi), donepezil (0.1 mg/kg, i.p.), and either velusetrag or TD-8954 (0.01 mg/kg i.p.) resulted in reversal of the scopolamine-induced cognitive deficit. Pharmacokinetic data indicated that the CNS penetration for all three 5-HT(4) receptor agonists was relatively low. However, the pharmacodynamic-pharmacokinetic relationships in the MWM model for velusetrag and TD-8954 were consistent with their respective receptor pharmacology (binding affinity and intrinsic efficacy) and CNS penetration properties. Collectively, these findings support a potential role for potent and efficacious 5-HT(4) receptor agonists in the treatment of AD.

To simulate a short segment of the aorta, we studied wave propagation in an elastic tube with a side branch balloon. The small balloon simulated the organ (group of arterioles). Ligation of this side branch would reduce the moduli of the higher harmonics when the length of the side branch was appropriate. Electrical analogy of vessels was used to analyze this phenomenon. This simulation can explain the ligation results we found in rats. It may also clarify the discrepancies between the prediction of the Womersley equation and the experimental results. We suggest that the aorta and the closely attached organ can produce coupled oscillation; theoretically, this structure is equivalent to a resonance circuit.

Tifluadom, a kappa-opioid agonist and cholecystokinin-A (CCK-A) receptor antagonist, was utilized as a model to prepare a series of 2-(aminomethyl)- and 3-(aminomethyl)-1,4-benzodiazepines. These compounds were tested in vitro as inhibitors of the binding of [125I]CCK to rat pancreas and guinea pig brain receptors. All compounds with IC50's less than 100 microM proved to have greater affinity for the CCK-A receptor, with the most potent analogue, 6e, having an IC50 of 0.16 microM. The benzodiazepines described in this study are simultaneously CCK-A and opioid receptor ligands. The ramification of this dichotomy on current concepts of peptide hormone action are discussed. These results further demonstrate the versatility of the benzodiazepine core structure for designing nonpeptide ligands for peptide receptors and the ability to fine-tune the receptor interactions of these benzodiazepines by appropriate structure modifications.

Antagonists of the B1 bradykinin receptor (B1R) offer the promise of novel therapeutic agents for the treatment of inflammatory and neuropathic pain. However, the in vivo characterization of the pharmacodynamics of B1R antagonists is hindered by the low level of B1R expression in healthy tissue and the profound species selectivity exhibited by many compounds for the human B1R. To circumvent these issues, we generated a transgenic rat expressing the human B1R under the control of the neuron-specific enolase promoter. Membranes prepared from whole brain homogenates of heterozygous transgenic rats indicate a B1R expression level of 30 to 40 fmol/mg; there is no detectable B1R expression in control nontransgenic rats. The pharmacological profile of the B1R expressed in the transgenic rat matches that expected of the human, but not the rat receptor. The mapping of the transgene insertion site to rat chromosome 1 permitted the development of a reliable assay for the identification of homozygous transgenic rats. Significantly, homozygous transgenic rats express 2-fold more B1R than heterozygous animals. Autoradiographic analyses of tissue sections from transgenic rats reveal that the B1R is broadly expressed in both the brain and spinal cord. The human B1R expressed in the transgenic rat functions in an in vitro contractile assay and thus has the potential to elicit a functional response in vivo. Using the humanized B1R transgenic rat, an assay was developed that is suitable for the routine evaluation of a test compound's ability to occupy the human B1R in the central nervous system.

A computational fluid dynamics code developed at Argonne National Laboratory was used to simulate turbulent mixing, combustion reaction, radiation heat transfer, and pollutant kinetics of the combustion flow in industrial melting furnaces. The code employs an integral approach to incorporate a lumped combustion reaction model in the flow calculation and a separate hybrid technique to perform pollutant kinetics calculations for NOx and soot. The code validated with experimental data collected from industrial furnaces, was used to evaluate the impacts of burner operation conditions on the energy efficiency of furnaces. The results indicate that the furnace configuration has a significant effect on the combustion efficiency; the burner injection velocity affects the flow penetration and the species mixing; and the burner injection angle has a significant impact on the flow patterns and heat transfer. The study demonstrates that CFD can be a useful tool for analyzing the combustion flow of an industrial furnace.

A comprehensive radiation heat transfer model and a reduced NOx kinetics model were coupled with a computational fluid dynamics (CFD) code and then used to investigate the radiation heat transfer, pollutant formation and flow characteristics in a glass furnace. The radiation model solves the spectral radiative transport equation in the combustion space of emitting and absorbing media, i.e., CO2, H2O, and soot and emission/reflection from the furnace crown. The advanced numerical scheme for calculating the radiation heat transfer is extremely effective in conserving energy between radiation emission and absorption. A parametric study was conducted to investigate the impact of operating conditions on the furnace performance with emphasis on the investigation into the formation of NOx.

Background Numerous studies have demonstrated the ability of angiotensin II (Ang II) receptor antagonists and angiotensin-converting enzyme (ACE) inhibitors to inhibit intimal hyperplasia after balloon dilatation of noncoronary arteries in small-animal models, suggesting an important role for Ang II in the response to injury. Although ACE inhibitors have not been similarly effective in nonhuman coronary models or in human restenosis trials, questions remain regarding the efficacy of ACE inhibitors against tissue ACE and the contributions of ACE-independent pathways of Ang II generation. Unlike ACE inhibitors, Ang II receptor antagonists have the potential to inhibit responses to Ang II independent of its biosynthetic origin. Methods and Results In separate studies, three Ang II receptor antagonists, including AT 1 -selective (L-158,809), balanced AT 1 /AT 2 (L-163,082), and AT 2 -selective (L-164,282) agents, were evaluated for their ability to inhibit vascular intimal thickening in a porcine coronary artery model of vascular injury. Preliminary studies in a rat carotid artery model revealed that constant infusion of L-158,809 (0.3 or 1.0 mg·kg −1 ·d −1 ) reduced the neointimal cross-sectional area by up to 37% measured 14 days after balloon dilatation. In the porcine studies, animals were treated with vehicle or test compound beginning 2 days before and extending 28 days after experimental angioplasty. Left anterior descending, left circumflex, and/or right coronary arteries were injured by inflation of commercially available angioplasty balloons with placement of coiled metallic stents. Infusion of L-158,809 (1 mg·kg −1 ·d −1 ), L-163,082 (1 mg·kg −1 ·d −1 ), or L-164,282 (1.5 mg·kg −1 ·d −1 ) in the study animals yielded plasma drug levels sufficient either to chronically block or, for L-164,282, to spare pressor responses to exogenous Ang II. Neither L-158,809, L-163,082, nor L-164,282 had statistically significant effects ( P =.12, P =.75, and P =.48, respectively, compared with vehicle-treated controls) on neointimal thickness (normalized for degree of injury) measured by morphometric analysis at day 28 after angioplasty. Conclusions These findings indicate that chronic blockade of Ang II receptors by either site-selective or balanced AT 1 /AT 2 antagonists is insufficient to inhibit intimal hyperplasia after experimental coronary vascular injury in the pig. The results further suggest that, unlike in the rat carotid artery, Ang II is not a major mediator of intimal thickening in the pig coronary artery.

Objectives/Hypothesis: Although numerous investigators have reported a bedside percutaneous dilatational tracheotomy (PDT) complication incidence similar to that of standard operative tracheostomy, others have proposed a learning curve for PDT resulting in increased complications early in individual or institutional experience with this procedure. The objective of this investigation is to characterize and quantify the proposed learning curve for PDT. Study Design: Prospective analysis of complication incidence for the first 100 PDT procedures performed in a local community hospital Department of General Surgery. Methods: Demographic data, patient disease variables, and patient anatomic features, as well as perioperative, postoperative, and late complications, were recorded prospectively. Patients were divided into sequential cohorts of 20 and were evaluated for complications at regular intervals. Results: Perioperative and late complication incidence was significantly higher in the first 20 patients who underwent PDT. However, postoperative complication incidence did not significantly vary with operator or institutional experience. In addition, patients with suboptimal anatomy were found to have a significantly increased complication incidence, independent of operator and institutional experience. Conclusions: Percutaneous dilational tracheotomy has an identifiable learning curve that is most prominent in the first 20 patients treated. Early experience with PDT should be obtained under controlled circumstances, ideally the operating suite. Although most complications occur during acquisition of early experience with PDT, certain life-threatening complications such as tube dislodgment or inability to complete procedure may occur even after extensive experience is obtained. Bedside PDT has an acceptable complication incidence, but any surgeon employing this technique must be prepared to perform immediate standard open tracheotomy to minimize potentially lethal complications of this elective procedure.

[3H]Mepyramine binds with high affinity to membranes from brain of human, rat, guinea-pig, rabbit and mouse with drug specificity indicating an association with histamine H1receptors. Considerable species differences occur in the affinity of [3H]mepyramine, with guinea-pig and human having 34 times greater affinity than rat, mouse or rabbit. The greater affinity of [3H]mepyramine in guinea-pig than in rat is attributable both to faster association and slower dissociation rates in guinea-pig. Species differences in affinity for H1 receptor sites occur for some antihistamines but not for others. Some tricyclic antidepressant and neuroleptic drugs are extremely potent inhibitors of [3H]mepyramine binding, exceeding in potency any H1 antihistamines examined. The tricyclic antidepressant doxepin and the neuroleptic clozapine are the most potent of all drugs examined in competing for [3H]mepyramine binding. The regional distribution of specific [3H]mepyramine binding differs considerably in the various species examined.

The use of gaseous chlorine in disinfecting municipal water supplies had enjoyed unquestioned acceptance for almost three quarters of a century, until 1975, when the National Organics Reconnaissance Survey (NORS) (1) revealed the presence of halogenated organic compounds resulting from chlorination in municipal supplies of 80 cities. These compounds, especially the trihalomethanes (THMs) such as chloroform (CHCh) and carbon tetra­ chloride (CC4), have been found to cause cancer in mice (2, 3). This revelation caused much concern to public health workers about the safety of our drinking water and called for a review of water disinfection and, in particular, water chlorination. The episode began in 1974 when the US Environmental Protection Agency (USEPA) (4) initiated a study of the methods of analysis of munici­ pal supplies in New Orleans. Using gaschromatography with a molecular spectrometer, two reports (5, 6) found THMs in two drinking water systems (mostly CHeI3) that were not present in the respective raw sources. It was concluded that the THMs were produced during chlorination. Because of the interest generated by, and the publicity that resulted from, these findings, the USEPA (1) undertook the much publicized NORS to deter­ mine the concentrations of six halogenated organic compounds, namely CHCI3, monobromochloroform (CHBrC12), dibromochloroform (CH­ Br2C1), bromoform (CHBr3)' carbon tetrachloride (CC4), and 1,2dichloroethane. The last two were known contaminants of the Mississippi River at New Orleans as well as of some other rivers, and there was no hard evidence that either of them was formed during the chlorination process.

We describe the SEM appearance of the rat endosteal bone lining cell ( BLC ) population, and the sequence of morphological changes of these cells as they self-incorporate into unmineralized bone matrix (osteoid), establish intercellular connections, and construct lacunae. The osteoblast/nascent osteocyte series was progressively unsheathed by gentle digestion of the osteoid with 0.25% collagenase. The osteoblasts which leave the polygonally packed BLC compartment rapidly develop numerous complexly branched processes that contact the processes elaborated by previous generations of maturing and mature osteocytes. As osteoblasts mature and approach the mineralization front, they appear to lose processes. The mature cells begin to form osteocyte lacunae by depositing an asymmetric perimeter of woven collagen fibrils, such that as the cells roof-over, the lacunae appear as pocketlike constructions. The collagen fibrils on the perilacunar matrix are oriented in a tangential or circular pattern, while those in the more distal matrix are arranged in a parallel pattern. With the completion of a lacuna, its wall appears to mineralize quickly, for lacunae could be recognized only when they are forming.

A simple, sensitive HPLC assay using flurescence detection was developed for quantitation of verapamil and its active metabolite, norverapamil in 100-200 μl blood samples from the rat. Baseline separation of verapamil, normverapamil and internal standard, propranolol, was attained within 14 minutes. Standard curves for verapamil and norverapamil were linear from 7 ng/ml to 1000 ng/ml with limit of detection of 4 ng/ml for both Compounds. the intraday and interday coefficients of variation in verapamil and norverapamil concentrations, determined from spiked whole blood samples, were less than 10%.

A new cerebral blood flow agent, 99Tcm-hexamethylpropyleneamine oxime (HM-PAO), was evaluated for early detection of acute cerebral infarction in conjunction with the transmission computed tomographic (CT) studies. The data from 22 cases were analysed. Results reveal that 99Tcm-HM-PAO enables the early detection of acute cerebral infarction prior to CT with rather proper depiction of the extent of physiological abnormality in the majority of patients. This promising result together with the lack of logistical problems will make 99Tcm-HM-PAO a useful and practical agent worldwide for diagnosing and managing acute cerebral infarction.

[3H]Flumitrazepam appears to label specific benzodiazepine receptors in vitro after i.v. injection in mice. Benzodiazepine potencies in reducing [3H]flunitrazepam binding in vivo correspond to pharmacological potencies and parallel relative affinities for [3H]flunitrazepam binding sites in isolated brain membranes. However, 50% occupation of [3H]-flunitrazepam sites by benzodiazzepines in vivo requires brain concentrations of the drugs about 1000 times higher than their Ki values for the binding sites in vitro. In pharmacologically active doses sodium pentobarbital, strychnine, picrotoxin and bicuculline fail to influence [3H]flunitrazepam binding in vivo.

Selective neuronal lesions have been utilized in efforts to localize binding sites in rat brain for β-adrenergic, γ-aminobutyric acid (GABA), histamine H 1 and benzodiazepine receptors. The various receptors respond differentially to lesions both in extent of change and in time course. After kainate lesions in the corpus striatum, benzodiazepine receptors are depleted up to 45% at 45–78 days but are unaffected after 7 days. By contrast striatal GABA receptors are increased at 7 days but depleted at later times. Thus both striatal benzodiazepine and GABA receptors appear to be associated at least in part with intrinsic neurons. In the cerebellum both benzodiazepine and GABA receptors are reduced in kainate treated rats and in Nervous mice, mutants which lack Purkinje cells. The most pronounced dissimilarity between benzodiazepine and GABA receptors occurs in Weaver mice, which selectively lack granule cells and display a 60% reduction in GABA receptors but a 40% augmentation in benzodiazepine receptors. A major portion of cerebellar GABA receptors, therefore, appear to be localized to granule cells. Striatal β-adrenergic receptors are reduced following intrastriatal kainate injections but are unaffected by cerebral cortex ablation, suggesting an association with intrinsic neurons but not with axon terminals of the corticostriate pathway. While intraventricular injections of 6-hydroxydopamine enhance [ 3 H]dihydroalprenolol binding to β-adrenergic receptors in the cerebral cortex and hippocampus, such binding is not augmented in the corpus striatum, brain stem, midbrain or thalamus-hypothalamus by this treatment. Moreover, medial forebrain bundle lesions, which destroy ascending adrenergic neurons, fail to alter cerebral cortical or striatal β-adrenergic receptors. Thus denervation-elicited increase in β-adrenergic receptors vary with brain region and the type of denervating lesion. Histamine H 1 -receptors are the most resistant of all to neuronal lesions. In the corpus striatum [ 3 H]mepyramine binding is unaffected by cerebral cortex ablation, nigral injections of 6-hydroxydopamine or brain stem hemisection. In the hippocampus, medial forebrain bundle lesions, intrahippocampal kainate injection, and fimbria and fornix transection largely fail to alter [ 3 H]mepyramine binding. Accordingly, a major portion of these receptors may be associated with nonneuronal elements such as glia or blood vessels.

Histamine H1- receptors labeled with [3H]mepyramine in rat brain show an age-dependent development. [3H]Mepyramine receptor density and histidine decarboxylase activity in whole rat brain reach adult levels at 25–30 days after birth and they attain 50% of adult level at day 10 and 17, respectively. The apparently later development of histidine decarboxylase activity in whole rat brain is partly accounted for by a biphasic developmental increase of this enzymatic activity in cerebral cortex. For all other brain regions examined, the development of histamine H1- receptors parallels that of histidine decarboxylase. The increase in [3H]mepyramine binding can be accounted for by an absolute increase in the numbers of the receptor sites, with no change in affinity. Subcellular fractionation studies indicate that histamine H1- receptors are predominantly associated with synaptosomal fractions derived from both newborn and adult rat.

Seventeen analogues of the selective, competitive cholecystokinin (CCK) antagonist asperlicin 1 were prepared. These compounds were tested as inhibitors of the binding of [125I]CCK to rat pancreas and guinea pig brain receptors. Compounds 4, 7, and 8 were more potent than asperlicin on the pancreatic CCK receptor. One analogue, 17, displayed potency equivalent to asperlicin on the pancreas CCK receptor and showed a marked improvement in aqueous solubility, thereby facilitating the use of this class of CCK antagonists in physiological and pharmacological studies.

A series of 4-substituted 4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepines was prepared by standard methodology. These compounds were tested in vitro as antagonists of the binding of [125I]cholecystokinin (CCK) to rat pancreas and guinea pig brain receptors and of the binding of [125I]gastrin to guinea pig gastric glands. All compounds proved to have greater affinity for the peripheral CCK receptor with some analogues having IC50's in the subnanomolar range. In vivo activity of selected compounds in mice is presented and the structure/activity profile of this class of benzodiazepines as CCK antagonists is discussed.

The antihistamine [3H]mepyramine binds to H1 histamine receptors in mammalian brain membranes. Potencies of H1 antihistamines at the binding sites correlate with their pharmacological antihistamine effects in the guinea pig ileum. Specific [3H]mepyramine binding is saturable with a dissociation constant of about 4 nM in both equilibrium and kinetic experiments and a density of 10 pmol per gram of whole kinetic experiments and a density of 10 pmol per gram of whole brain. Some tricyclic antidepressants are potent inhibitors of specific [3H]mepyramine binding. Regional variations of [3H]mepyramine binding do not correlate with variations in endogeneous histamine and histidine decarboxylase activity.

Identifying individuals with a deficient capacity for oxidative drug metabolism is of increasing clinical importance. Dextromethorphan (DM) is gaining wide acceptance as a probe drug to characterize individual expression of a specific cytochrome P-450 isozyme. The thin-layer chromatography (TLC) technique described in the present study is a rapid and inexpensive alternative to the methods currently available for assessing the urinary metabolic profile of DM. Sixty-five healthy volunteers participated in the study by ingesting 213 mmol DM and collecting all urine for the ensuing 8 h. Urine samples were analyzed by TLC and high-performance liquid chromatography (HPLC) after treatment with beta-glucuronidase. Based on the relative color intensities of DM and its O-demethylated metabolite, dextrorphan, the TLC analysis provided an accurate phenotype assessment. A greater intensity of the parent drug relative to the metabolite indicates a poor metabolizer phenotype whereas a reversed relative intensity indicates the extensive metabolizer phenotype. The phenotype assignments made by TLC were verified by comparison with the quantitative results (based on metabolic ratios) obtained from HPLC analysis. Complete agreement was found between the two methods. The routine implementation of phenotype determination into clinical protocols can be realized with this facile TLC technique.

1. Drug administration studies using diisopropylamine dichloroacetate (DADA) and diisopropylamine (DIPA) were conducted in Thoroughbred and Standardbred horses to assess physiological effects and develop detection methods. 2. Four horses received 0.08 mg DADA/kg body wt and showed no changes in heart and respiratory rates or body temperature as measured over a 1-hr period after administration. A transient diuretic effect was found to occur in 2 mares dosed with 0.80 mg DADA/kg body wt. 3. A qualitative detection method using thin-layer chromatography was developed to detect DIPA, the major metabolite of DADA in equine urine. A quantitative detection method (lower limit of detection 0.5 micrograms/ml urine) for this metabolite was also developed using gas chromatography. 4. Neither DADA or the free base, DIPA, were detectable in equine blood samples using the above-mentioned methodologies.

Agonist, but not antagonist, interactions with histamine H2-receptors labeled by [3H]mepyramine are regulated selectively by sodium, divalent cations, and guanine nucleotides. Sodium decreases the affinity of histamine and the agonist 2-amino-ethylpyridine for [3H]mepyramine sites in guinea pig brain membranes up to 10-fold. The effect of sodium is exerted to a lesser extent by lithium, while potassium and rubidium are much weaker. Guanine nucleotides also decrease the affinity of histamine for H1 binding sites about twofold. GTP and its nonmetabolized analogue GMP-PNP as well as GDP exert similar effects, while GMP, ATP, ADP, and AMP are inactive. The effects of GTP and sodium on histamine interactions with H1-receptors are additive. By contrast, certain divalent cations enhance the potency of histamine at H1-receptors. Manganese is most potent, while magnesium is almost as active as manganese and calcium is essentially inactive. Sodium, divalent cations, and guanine nucleotides have negligible effects on the interactions of antihistamines with H1-receptors.

3S(-)-N-(2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4- benzodiazepine-3-yl)-1H-indole-2-carboxamide (L-364,718) interacted in a competitive manner with rat pancreatic cholecystokinin (CCK) receptors as determined by Scatchard analysis of the specific binding of 125I-labeled CCK. The affinity of L-364,718 for both pancreatic (IC50, 81 pM) and gallbladder (IC50, 45 pM) CCK receptors in radioligand binding assays greatly exceeded that of other reported nonpeptide CCK antagonists and was similar to that of CCK itself. In vitro functional studies utilizing CCK-induced contractions of the isolated guinea pig ileum and colon further demonstrated that L-364,718 acts as a competitive CCK antagonist, which lacks agonist activity and has a similar high affinity in these tissues (pA2, 9.9). L-364,718 exhibited a very high selectivity for peripheral CCK receptors relative to brain CCK, gastrin, and various other peptide and nonpeptide receptors in both in vitro radioligand and isolated tissue assays. In vivo, low intravenous doses of L-364,718 (0.1 mg/kg) markedly antagonized the contractions of the guinea pig gallbladder produced by intravenous administration of CCK for at least 2 hr. Administered orally, L-364,718 (ED50, 0.04 mg/kg) was highly effective as an antagonist of CCK-induced inhibition of gastric emptying in mice. The biochemical and pharmacological properties of L-364,718--namely, very high affinity and selectivity for peripheral CCK receptors, long-lasting in vivo efficacy, and oral bioavailability--makes this compound a powerful tool for investigating the physiological and pharmacological actions of CCK, and possibly its role in gastrointestinal disorders.

The effect of valproic acid on carbamazepine epoxidation in the perfused liver was investigated in two separate studies. In study I, significant decreases were observed both in the intrinsic clearance of carbamazepine and the intrinsic formation clearance of carbamazepine-epoxide in the presence of therapeutic concentrations of valproate. The same inhibitory effect of valproate was also observed in liver preparations from a group of animals pretreated with carbamazepine. Study II focused on the effect of valproate and carbamazepine on the apparent Michaelis-Menten parameters (Vmax,m, Km,m) associated with the intrinsic formation clearance of carbamazepine-epoxide in the perfused liver. Valproate had no statistically significant effect on either the Vmax,m or the Km,m of epoxidation, although the Km,m value was 43% higher in the presence of valproate. However, the ratio of Vmax,m and Km,m (intrinsic formation clearance) was significantly reduced by valproate. The Vmax,m and Km,m values obtained in study II predicted a significant decrease in the intrinsic formation clearance of carbamazepine-epoxide, consistent with the results of study I. Carbamazepine pretreatment was associated with significant increases in apparent Vmax,m and Km,m of epoxide formation.

A series of 4-substituted 4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepines was prepared by standard methodology. These compounds were tested in vitro as antagonists of the binding of [125I]cholecystokinin (CCK) to rat pancreas and guinea pig brain receptors and of the binding of [125I]gastrin to guinea pig gastric glands. All compounds proved to have greater affinity for the peripheral CCK receptor with some analogues having IC50's in the subnanomolar range. In vivo activity of selected compounds in mice is presented and the structure/activity profile of this class of benzodiazepines as CCK antagonists is discussed.

Cholecystokinin octapeptide (CCK-8) (EC50 = 5 nM) was considerably more potent than pentagastrin (EC50 = 161 nM) in stimulating acid secretion in the isolated perfused mouse stomach suspended in a medium containing a phosphodiesterase inhibitor. The maximum acid response to CCK-8 was not significantly different from that produced by pentagastrin. The nonselective CCK/gastrin antagonist, proglumide, but not the selective CCK antagonist, asperlicin, antagonized the acid response to both pentagastrin and CCK-8. The data suggest that CCK-8 acts as a potent, full agonist on gastrin receptors for acid secretion in the isolated mouse stomach.