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Biomedical subjects

S J Peroutka

Publications and source records attributed to S J Peroutka.

At least 91 records · Page 5Linked to original sources
PubMed1989

Distribution of cholecystokinin receptors in the dorsal vagal complex and other selected nuclei in the human medulla.

Cholecystokinin receptors were localized in human brainstem by quantitative autoradiography, using [3H]cholecystokininoctapeptide. Receptor densities were highest in the caudal medial region of the nucleus of the solitary tract (NTS). High densities also were present in the dorsal motor nucleus of the vagus, the principle nucleus of the inferior olive, the ventral region of the NTS, and the area postrema.

Aged↗
PubMed1989

Sumatriptan (GR 43175) interacts selectively with 5-HT1B and 5-HT1D binding sites.

The ability of sumatriptan (GR 43175; 3-[2-dimethylamino]ethyl-N-methyl-1H-indole-5 methane sulphonamide) to interact with 13 neurotransmitter receptor sites was determined using radioligand binding techniques. Sumatriptan displayed the highest affinity for 5-HT1D (Ki = 17 nM) and 5-HT1B (Ki = 27 nM) binding sites and was slightly less potent at 5-HT1A binding sites (Ki = 100 nM). By contrast, sumatriptan was essentially inactive (Ki greater than 10,000 nM) at each of the 10 other binding sites analyzed. These data indicate that sumatriptan interacts selectively with 5-HT1B and 5-HT1D sites and suggest that these interactions may be the basis of its apparent efficacy in the acute treatment of migraine.

Animals↗
PubMed1989

1-(m-chlorophenyl)piperazine (mCPP) interactions with neurotransmitter receptors in the human brain.

The affinity of 1-(m-chlorophenyl)piperazine (mCPP) for 11 neurotransmitter receptor binding sites was determined in human brain membranes. mCPP is essentially equipotent at all 5-hydroxytryptamine (5-HT) receptor subtypes (IC50 values ranging from 360 to 1300 nM). The drug displays similar affinity (IC50 = 570 nM for alpha 2-adrenergic receptors labeled for 3H-rauwolscine. mCPP is less potent at alpha 1- and beta-adrenergic, dopamine, and muscarinic cholinergic receptors (IC50 values 2500-24,000 nM). mCPP is inactive at both benzodiazepine receptors and the 5-HT uptake sites at concentrations below 100,000 nM. These data demonstrate that mCPP displays similar potency for multiple neurotransmitter receptor binding sites in human brain.

Adult↗
PubMed1989

Identification of 5-hydroxytryptamine1D binding sites in human brain membranes.

High-affinity, specific 3H-5-hydroxytryptamine (5-HT) binding was analyzed in membrane homogenates of human frontal cortex, caudate, and globus pallidus. 5-HT1A and 5-HT1C binding sites were pharmacologically blocked using 100 nM 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT) and 100 nM mesulergine, respectively. The majority of 5-HT1 sites remained in each of the three brain regions under these conditions. The pattern of nucleotide interactions with these binding sites (GppNHp = GTP = GDP greater than GMP = adenine nucleotides) suggests a possible linkage to a G protein. RU 24969 competition studies confirmed the absence of 5-HT1B binding sites in human cortex, caudate, and globus pallidus. Drug interactions with putative 5-HT1D binding sites in bovine caudate membranes correlated significantly with their affinities for human membrane recognition sites labeled by 3H-5-HT in the presence of 100 nM 8-OH-DPAT + 100 nM mesulergine. We conclude that the majority of 3H-5-HT labeled recognition sites in human cortex, caudate, and globus pallidus represent 5-HT1D binding sites.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1989

Differential interactions of traditional and novel antiemetics with dopamine D2 and 5-hydroxytryptamine3 receptors.

The affinities of 11 drugs for both dopamine D2 and 5-hydroxytryptamine3 (5-HT3) receptor sites were determined in brain membranes. The five "traditional" antiemetics (chlorpromazine, prochlorperazine, droperidol, fluphenazine, and domperidone) displayed high affinity (less than 20 nM) for dopamine D2 receptors in corpus striatum but were inactive at 5-HT3 receptors. In contrast, five recently developed 5-HT3 antagonists (BRL 43694, ICS 205-930, zacopride, Lilly 278584, and MDL 72222) displayed nanomolar affinity for the 5-HT3 site but were inactive (greater than 10,000 nM) at the dopamine D2 receptor. Metoclopramide was unique among these agents in that it was similarly potent at dopamine D2 (240 +/- 60 nM) and 5-HT3 (120 +/- 30 nM) receptors.

Animals↗
PubMed1989

Hallucinogenic drug interactions with neurotransmitter receptor binding sites in human cortex.

The binding affinities of four hallucinogenic agents were analyzed at nine neurotransmitter binding sites in human cortex. d-Lysergic acid diethylamide (d-LSD), N,N-dimethyltryptamine (DMT), 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and 1-(2,5-dimethoxy-4-bromophenyl)-2-aminopropane (DOB) display highest affinity for the recently identified "DOB binding site" labeled by 77Br-R(-)DOB. The phenalkylamines, DOI and DOB, display subnanomolar affinity for the 77Br-R(-)DOB-labeled site, whereas the indolealkylamines, d-LSD and DMT, display nanomolar affinity for this site. d-LSD was the most potent of the four hallucinogens at six of the other eight sites analyzed in this study. All four hallucinogens also display high affinity for the 5-hydroxytryptamine2 (5-HT2) receptor subtype, with potencies ranging from 4 to 360 nM. Marked differences in relative affinities were observed between the indolealkylamines and the phenalkylamines at the 5-HT1A, 5-HT1D, and DOB binding sites. These rank-order differences in affinities are likely to account for the differing effects of these agents in various biochemical and physiological assays.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1989

5-Hydroxytryptamine receptor "families".

The identification of multiple receptor subtypes for 5-hydroxytryptamine (5-HT) made by using radioligand binding techniques proliferated at a brisk rate in the 1980s. The application of molecular biological techniques to 5-HT receptor studies is likely to lead to an expansion rather than a reduction in the number of distinct 5-HT receptor subtypes. Although the current status of 5-HT receptor pharmacology may appear to be overwhelmingly confusing to most investigators, the evolving data suggest that 5-HT receptor subtypes can be categorized into three major families. Each family consists of multiple receptor subtypes that share similarities in their molecular biological, pharmacological, biochemical, and/or physiological properties. This review provides a summary of recent data as well as a framework for the classification of 5-HT receptor subtypes.

Animals↗
PubMed1989

Characterization of [3H]quipazine binding to 5-hydroxytryptamine3 receptors in rat brain membranes.

[3H]Quipazine was used to label binding sites in rat brain membranes that display characteristics of a 5-hydroxytryptamine3 (5-HT3) receptor. The radioligand binds with high affinity (KD, 1.2 +/- 0.1 nM) to a saturable population of sites (Bmax, 3.0 +/- 0.4 pmol/g of tissue) that are differentially located in the brain. Specific [3H]quipazine binding is not affected by guanine or adenine nucleotides. ICS 205-930, BRL 43964, Lilly 278584, and zacopride display less than nanomolar affinity for these sites whereas MDL 72222 is approximately one order of magnitude less potent. The pharmacological profile of the binding site is in excellent agreement with that of 5-HT3 receptors characterized in peripheral physiological models. We conclude that [3H]quipazine labels a 5-HT3 receptor in the rat CNS.

Animals↗
PubMed1989

Evidence for distinct 5-hydroxytryptamine2 binding site subtypes in cortical membrane preparations.

5-Hydroxytryptamine (5-HT) displays a sixfold higher affinity for 5-HT2 binding sites labeled by [3H]ketanserin in rat (IC50 = 200 +/- 40 nM) and human (IC50 = 190 +/- 50 nM) cortex than for 5-HT2 sites in bovine cortex (IC50 = 1,200 +/- 130 nM). The Hill slopes of the 5-HT competition curves are 0.67 +/- 0.04 in rat, 0.69 +/- 0.08 in human, and 0.96 +/- 0.02 in bovine cortex. Scatchard analysis of (+/-)-[3H]4-bromo-2,5-dimethoxyamphetamine ([3H]DOB) binding in the rat indicates a population of binding sites with a KD of 0.38 +/- 0.04 nM and a Bmax of 1.5 +/- 0.05 pmol/g tissue. In contrast, specific [3H]DOB binding cannot be detected in bovine cortical membranes. These data indicate that species variations exist in 5-HT2 binding site subtypes and that [3H]ketanserin appears to label a homogeneous population of 5-HT2 binding site subtypes in bovine cortex.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1989

Nifedipine versus propranolol for the initial prophylaxis of migraine.

We conducted a randomized open-labeled study of nifedipine versus propranolol for the initial prophylaxis of migraine. Propranolol was effective in 67% of patients (12/18) and well tolerated. Nifedipine was effective in only 30% of patients (6/20). The lack of overall efficacy of nifedipine was attributable to a high incidence of side effects, including an unusual symptom complex resembling erythromelalgia. These side effects led 45% (9/20) of the nifedipine patients to withdraw from the study within two weeks. By contrast, no patient (0/18) withdrew from the study within the first 2 weeks of propranolol therapy. We conclude that nifedipine is not an agent of first choice for the prophylaxis of migraine.

Adult↗
PubMed1989

Comparative neuropharmacology of dihydroergotamine and sumatriptan (GR 43175).

The potency of dihydroergotamine (DHE) was determined at 13 neurotransmitter receptors using radioligand binding techniques. DHE is a potent agent (i.e. affinity value less than 100 nM) at 5-hydroxytryptamine1A (5-HT1A), 5-HT1C, 5-HT1D, 5-HT2, dopamine2, alpha1- and alpha2-adrenergic binding sites. DHE displays moderate affinity (i.e. affinity values = 100 - 1000 nM) for beta-adrenergic and dopamine1 sites and is completely inactive at 5-HT3, muscarinic and benzodiazepine receptors. These results were then compared to similar data on sumatriptan (formerly called GR 43175), a novel acute anti-migraine agent. The only pharmacological property shared by both agents is high affinity for 5-HT1D and 5-HT1A receptors. Therefore, these data suggest that 5-HT1D and/or 5-HT1A receptors may play an important role in the pathophysiology of migraine.

Animals↗
PubMed1989

The clinical utility of pharmacological agents that act at serotonin receptors.

The past decade has seen important advances in the clinical utility of serotonergic agents. The putative novel anxiolytic effects of 5-HT1A partial agonists such as buspirone, the antidepressant effects of selective serotonin (5-HT) uptake blockers such as fluoxetine, and the unique and potent antiemetic effects of 5-HT3 antagonists in cancer chemotherapy are excellent examples of the clinical relevance of selective 5-HT receptor agents. The increasing ability to modulate serotonergic neurotransmission through distinct 5-HT receptor subtypes should greatly facilitate the analysis of 5-HT in both normal and abnormal human brain function.

Animals↗
PubMed1989

Nifedipine in the prophylaxis of classic migraine: a crossover, double-masked, placebo-controlled study of headache frequency and side effects.

Twenty-four patients with classic migraine attacks were treated with either nifedipine or placebo for up to 12 weeks. No significant differences were observed between the nifedipine (2.1 +/- 0.2) and placebo (2.3 +/- 0.2) treatment groups in the monthly frequency of headaches. However, the incidence of side effects was significantly greater (p less than 0.001) in the nifedipine (54% of patients) than in the placebo (8% of patients) treatment groups.

Clinical Trials as Topic↗
PubMed1989

Cyclic adenosine 3',5'-monophosphate metabolism in activated T-cell clones.

The role of cAMP in lymphocyte proliferation was investigated in the response of a monoclonal T-cell population to a specific antigen and compared to the response to interleukin-2 (IL-2) and allogeneic cells. Myelin basic protein (MBP)-reactive and encephalitogenic T-cell clones were established from long-term lines derived from SJL/J (H-2s) mice. The clone 4b.14a recognizes the peptide sequence 89-101 of the MBP molecule in association with 1-As products of the major histocompatibility complex (MHC). Incubation of 4b.14a cells with syngeneic antigen-presenting cells, previously pulsed with the 89-101 synthetic peptide or with 80 U/ml of IL-2, or allogeneic H-2Ik cells, resulted in a significant increase in the accumulation of intracellular cAMP. This increase was preceded by a peak in membranal adenylate cyclase (AC) activity. Parallel time kinetics but significantly higher cAMP production and AC activity were observed when the cells were treated with pertussis toxin. At the same concentrations the toxin inhibits cellular proliferative responses, assayed by [3H]thymidine incorporation. Our results indicate the involvement of cAMP as a positive signal in the activation of the 4b.14a clone.

Animals↗
PubMed1989

Differentiation of 5-hydroxytryptamine2 receptor subtypes using 125I-R-(-)2,5-dimethoxy-4-iodo-phenylisopropylamine and 3H-ketanserin.

The radioligand binding characteristics of 125I-R-(-)4-iodo-2,5-dimethoxyphenylisopropylamine [125I-R-(-)DOI] and 3H-ketanserin were compared in rat and bovine cortical membranes. In rat cortex, 125I-R-(-)DOI labels a relatively low density of binding sites (Bmax = 2.5 +/- 0.2 pmol/gm tissue) with high affinity (KD = 0.63 +/- 0.09 nM). In bovine cortex, specific binding of 125I-R-(-)DOI represents less than 20% of total binding at radioligand concentrations above 0.6 nM, and, therefore, the data cannot be analyzed adequately by Scatchard transformation. By contrast, 3H-ketanserin displays saturable, specific high-affinity binding in both rat cortex (KD = 1.0 +/- 0.1 nM; Bmax = 11 +/- 0.4 pmol/gm tissue) and bovine cortex (KD = 1.2 +/- 0.2 nM; Bmax = 5.3 +/- 0.4 pmol/gm tissue). Ki values for 30 drugs were determined for 125I-R-(-)DOI-labeled sites in rat cortex and 3H-ketanserin-labeled sites in bovine cortex. 5-Hydroxytryptamine (5-HT) displays 250-fold higher selectivity for the 125I-R-(-)DOI-labeled sites (Ki = 3.0 +/- 0.7 nM) than for the 3H-ketanserin-labeled sites (Ki = 750 +/- 50 nM). Structural congeners of R-(-)DOI display 80- to 160-fold higher affinity for the 125I-R-(-)DOI binding site than for the 3H-ketanserin-labeled binding site. d-LSD and putative 5-HT2 antagonists are approximately equipotent at both sites. Significant correlations were found between drug affinities for 125I-R-(-)DOI-labeled sites in rat cortex and putative 5-HT2A sites labeled previously by 77Br-R-(-)DOB (r = 0.93, p less than 0.01), putative 5-HT2B sites labeled by 3H-ketanserin in bovine cortex (r = 0.63, p less than 0.01), and 5-HT1C binding sites that have been characterized by other investigators (r = 0.78, p less than 0.01). No significant correlations were found between drug affinities for 125I-R-(-)DOI-labeled sites in rat cortex and 5-HT1A, 5-HT1B, 5-HT1D, or 5-HT3 sites, as determined by previous investigators. We conclude that 125I-R-(-)DOI labels a novel 5-HT binding site subtype (tentatively designated the 5-HT2A binding site) that is present in rat cortex but is either absent or minimally present in bovine cortex. By contrast, 3H-ketanserin labels both the putative 5-HT2A site in rat cortex as well as a separate, distinct recognition site that is present in both rat and bovine cortex, tentatively designated the 5-HT2B site.

Amphetamines↗
PubMed1989

Three-dimensional steric molecular modeling of the 5-hydroxytryptamine3 receptor pharmacophore.

A computer-based three-dimensional steric molecular model of the 5-hydroxytryptamine3 (5-HT3) receptor pharmacophore was defined on the basis of radioligand binding data. Analysis of published data led to the identification of 19 different chemical structures that share only a single known pharmacological property, i.e., less than 10 nM affinity for the 5-HT3 receptor. These 19 compounds were then categorized into seven chemical families, which derive from six main steric "core" structures. From the composite analysis of all 19 potent agents, nine steric chemical criteria were derived, which can be used to describe the 5-HT3 receptor pharmacophore. This information was then used to explain the 5-HT3 receptor inactivity of atrophine, a compound that differs structurally from ICS 205-930 in the steric properties of only a single key atom. The steric chemical information was also used to predict the activity of serotonergic compounds that had never been analyzed at 5-HT3 receptor binding sites. Two serotonergic drugs that meet all nine steric criteria were found to be active at the 5-HT3 receptor binding site (i.e., pizotifen, KI = 42 +/- 10 nM, and clozapine, KI = 52 +/- 8 nM). By contrast, two serotonergic agents that do not meet the criteria were found to be inactive at the 5-HT3 receptor binding site (i.e., ipsapirone and pirenperone, KI values greater than 1000 nM). This computer-based steric molecular modeling approach allows for the analysis and identification of 5-HT3 receptor-active agents with minimal dependence upon animals and radioactive compounds.

Animals↗