Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Selective chronic lesions of the dorsal raphe nucleus or combined lesions of the dorsal and median raphe nuclei did not significantly change the in vivo tyrosine hydroxylation in the striatum as measured by the DOPA accumulation after decarboxylase inhibition. Neither did acute combined lesions of the raphe nuclei, nor did electrical stimulation of the dorsal raphe nucleus have any significant effect. p-Chloroamphetamine (PCA, 20 mg/kg, i.p.) and p-chlorophenylalanine (PCPA, 400 mg/kg, i.p.), known inhibitors of the 5-hydroxytryptamine (5-HT) synthesis, significantly decreased the DOPA accumulation. The increase in DOPA accumulation observed after LSD (0.5 mg/kg, i.p.) or BOL (0.5 mg/kg, i.p.) was seemingly unaffected by pretreatment with PCA or PCPA and also after lesion of the dorsal raphe nucleus. The results suggest that the effect of LSD or BOL on the DOPA accumulation in the striatum is not mediated via a 5-hydroxytryptaminergic control mechanism originating in the dorsal raphe nucleus. A control mediated via the median raphe nucleus cannot be excluded, since LSD did not increase the DOPA accumulation after combined chronic raphe lesions. Such a control would also be in agreement with our previous results suggesting that hte DOPA generation after LSD is controlled by 5-HT receptors.
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PMID:The effect of lysergic and diethylamide (LSD) and 2-bromolysergic acid diethylamide (BOL) on the striatal DOPA accumulation: influence of central 5-hydroxytryptaminergic pathways. 2 17

RU 31156, the tris-(hydroxymethyl)-aminomethane salt of 7-(S-methylsulphonimidoyl)-5-(n-hexyl)-xanthen-9-one-2-carboxylic acid has been found to be a potent inhibitor of experimental immediate hypersensitivity reactions in vivo. In the IgE-mediated rat PCA test, RU 31156 had an ED50 of 0.0046 (00037--0.0057) mg/kg which compared to a figure of 1.21 (1.04--1.42) mg/kg for disocium cromoglycate (DSCG), both compounds being administered intravenously. RU 31156 was also active when administered orally, having an ED50 of 0.19 (0.07--0.30) mg/kg when given 10 min before antigen. RU 31156 partially inhibited an IgG-mediated PCA reaction in the rat. Both RU 31156 and DSCG inhibited anaphylactic bronchoconstriction in the rat, giving bell-shaped dose-response curves. From the upward part of the curves, approximate ED30 values of 0.02 and 2.0 mg/kg were obtained for RU 31156 AND DSCG respectively. Anaphylactic bronchoconstriction in the guinea-pig was not affected by RU 31156 and pinnal anaphylaxis was inhibited at only relatively high doses of 1--10 mg/kg i.v. The effects of both histamine and 5-hydroxytryptamine in the mouse pinna were not affected by RU 31156. In PCA experiments, RU 31156 showed self-tachyphylaxis following both intravenous and oral administration. It also showed cross-tachyphylaxis with DSCG, indicating that these compounds are likely to share a similar mode of action.
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PMID:Inhibition of experimental immediate hypersensitivity reactions by a novel xanthone, RU 31156. 2 34

The skin of congenitally athymic nu/nu mice is rich in mast cells which stain metachromatically, contain histamine and 5-hydroxytryptamine, and participate in the PCA reaction. Mast cells of athymic mice have thus the attributes of normal mast cells.
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PMID:Mast cells in the skin of normal, hairless and athymic mice. 81 24

Administration of p-chloroamphetamine (PCA, 10 mg/kg i.p. on two occasions) to rats resulted in a severe depletion of [3H]paroxetine binding sites, a measure of presynaptic serotonergic terminals, in both cortex and hippocampus, but did not affect [3H]8-hydroxy-2-(di-n-propylamino)tetralin [( 3H]8-OH-DPAT) binding or 5-hydroxytryptamine (5-HT)-induced inhibition of forskolin-stimulated adenylate cyclase in hippocampal membranes. Administration of either imipramine (15 mg/kg i.p. for 2 weeks) or lithium (0.2% for 2 weeks) to PCA-treated rats did not affect [3H]8-OH-DPAT binding but reduced the degree of inhibition of forskolin-stimulated adenylate cyclase by 5-HT in hippocampal membranes. It is concluded that the effects of imipramine and Li+ on 5-HT1A receptor-mediated responses in the hippocampus are exerted postsynaptically, possibly at a level distal to the receptor.
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PMID:Chloroamphetamine did not prevent the effects of chronic antidepressants on 5-hydroxytryptamine inhibition of forskolin-stimulated adenylate cyclase in rat hippocampus. 165 66

p-Chloro-alpha-fluoromethylphenylethylamine (fluoro-p-chloroamphetamine) (FpCA) has been shown in acute studies to be a less potent depletor of the neurotransmitter amine 5-hydroxytryptamine (5-HT) in brain than is p-chloroamphetamine (pCA). Gas chromatographic assay procedures for FpCA and PCA have been developed in our laboratories and applied to preliminary measurements in brain tissue from rats injected intraperitoneally with pCA or FpCA. Groups of male Sprague-Dawley rats were injected with pCA (0.03 mmol/kg) or FpCA (0.05 or 0.1 mmol/kg) and killed 1, 2, or 4 hr later. The brains were analyzed for the halogenated amphetamines by gas chromatography with electron-capture detection (GC-ECD) following derivatization with pentafluorobenzenesulfonyl chloride (for pCA) or trichloroacetic anhydride (for FpCA). At the 0.05-mmol/kg dose, FpCA attained lower brain concentrations at 1, 2, and 4 hr after injection than did pCA at a considerably lower dose (0.03 mmol/kg). Even at the higher dose of FpCA used (0.10 mmol/kg), where concentrations of FpCA were higher than those of pCA initially, concentrations of FpCA had dropped below those of pCA by 4-hr. These preliminary results indicate that FpCA attains lower brain concentrations and is eliminated from the brain more rapidly than is the parent drug, pCA. However, differences in potency between FpCA and pCA on 5-HT depletion cannot be explained fully on the basis of obtained brain levels of the drug as even at time intervals where FpCA levels were higher than or equal to those of pCA, there was less depletion of 5-HT by the former drug.
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PMID:Analysis of p-chloroamphetamine and a side-chain monofluorinated analogue in rat brain. 206 83

By use of a simple anticonflict procedure (Vogel test), it was demonstrated that L-pyroglutamic acid (L-pyrrolidone carboxylic acid [L-PCA]), an amino acid naturally occurring in mammalian tissues and fluids, possesses anxiolytic activity. This tissues and fluids, possesses anxiolytic activity. This effect was stereospecific (D-PCA was inactive) and, in the rat, it was not associated with a decrease in motor activity. Ro 15-1788, a benzodiazepine antagonist, did not modify L-PCA actions. Furthermore, anxiolytic doses of the amino acid did not change the content of 5-hydroxytryptamine (5-HT) or of 5-hydroxyindoleacetic acid (5-HIAA) in the rat cortex and hippocampus. These results suggest that the mechanism of the anxiolytic activity of L-PCA is different from that of the benzodiazepines and of 5-HT1a agonists.
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PMID:A new endogenous anxiolytic agent: L-pyroglutamic acid. 245 80

1. Reserpine (2.5 mg kg-1 i.p.) decreased rat brain 5-hydroxytryptamine (5-HT) by 86% 24 h later but most components of the 5-HT-dependent behavioural syndrome induced by p-chloroamphetamine (PCA, 5 mg kg-1 i.p.) or 5-methoxy-N,N-dimethyltryptamine (5-MeODMT, 5 mg kg-1 i.p.) over 1 h after administration were unaffected. However, Straub tail was increased after giving PCA or 5-MeODMT and head weaving was decreased after giving 5-MeODMT. 2. Frontal cortex extracellular 5-HT concentrations of vehicle pretreated rats before injection of PCA, as calculated from dialysate 5-HT concentrations, were about 1/1000th of corresponding brain values. Extracellular 5-hydroxyindoleacetic acid (5-HIAA) and brain values were comparable with each other. Dialysate 5-HT increased after PCA with peak values at 20-40 min. 3. Reserpine pretreatment reduced dialysate 5-HT concentration before PCA was given but the net increase (AUC) over the 1 h after PCA did not differ significantly from that seen in animals pretreated with vehicle. Dialysate 5-HIAA values slowly decreased after PCA injection in both reserpine and vehicle pretreated groups. 4. The results suggest that PCA causes the 5-HT syndrome by releasing 5-HT from the neuronal cytoplasm but that physiological release of 5-HT occurs from vesicular stores.
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PMID:An in vivo dialysis and behavioural study of the release of 5-HT by p-chloroamphetamine in reserpine-treated rats. 272 Mar 8

Antidepressant drugs and electroconvulsive shock (ECS) given repeatedly increase the density of brain alpha 1-adrenoceptors. However, the mechanism involved in this effect is unknown. To study the role of presynaptic noradrenaline (NA) and 5-hydroxytryptamine (5-HT) nerve terminals in the above phenomenon we examined the density of [3H]prazosin binding sites in the rat cerebral cortex following a prolonged treatment with imipramine and citalopram (10 mg/kg po, twice daily for 14 days) or ECS (once daily for 8 days) in animals pretreated with DSP-4 (62.5 mg/kg ip) and p-chloroamphetamine (PCA, 2 x 10 mg/kg ip). In normal rats imipramine, citalopram and ECS increased the density (Bmax) of [3H]prazosin binding sites by 30, 25 and 19%, respectively. DSP-4 pretreatment abolished the effect of imipramine and citalopram but not that of ECS. Pretreatment with PCA influenced the effect of neither antidepressant drugs nor ECS. Our results indicate that the "up-regulation" of alpha 1-adrenoceptors induced by imipramine and citalopram, but not by ECS, depends on intact NA nerve terminals. They also show that the 5-HT system is not involved in the above phenomenon.
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PMID:Long-term effect of antidepressant drugs and electroconvulsive shock on brain alpha 1-adrenoceptors following destruction of noradrenergic or serotonergic nerve terminals. 285 81

LG 30435 (N-methylmequitazine) was assayed in passive lung (PLA) and cutaneous (PCA) anaphylaxis in guinea-pigs and rats. At doses from 0.3 to 3 mumol kg-1 i.v., it produced a dose-dependent inhibition of guinea-pig PLA and of rat PCA and PLA, while the parent compound was ineffective or poorly effective up to 3 mumol kg-1. An attempt was made to elucidate the mechanism of LG 30435's action in these anaphylactic models, by means of various antagonists. It was tentatively concluded that different mechanisms are involved in the protective action of LG 30435 in each of the three models: histamine antagonism, possibly accompanied by an inhibition of the effects of peptido-leukotrienes in guinea-pig PLA; histamine antagonism in rat PCA and 5-hydroxytryptamine antagonism in rat PLA, possibly accompanied by a mast-cell stabilizing action in both cases. LG 30435 is devoid of smooth muscle relaxant effects on the airways and its demonstrated anticholinergic and anti-PAF effects do not appear to be involved in its antiallergic action.
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PMID:Mechanisms of the antiallergic action of N-methylmequitazine (LG 30435). 290 Mar 3

Depletion of 5-hydroxytryptamine (5-HT) in mice was produced by intracerebroventricular injection of 5,7-dihydroxytryptamine (5,7-DHT, 80 micrograms) or by systemic injections of p-chloroamphetamine (PCA, 3 X 40 or 4 X 40 mg/kg), p-chlorophenylalanine (PCPA, 5 X 400 or 14 X 400 mg/kg) or combined PCA (3 X 40 mg/kg) + PCPA (11 X 400 mg/kg). Neither of the pretreatments altered nociception in the increasing temperature hot-plate test, whereas hyperalgesia was demonstrated in 5,7-DHT lesioned animals in the tail-flick test. 5,7-DHT-pretreatment enhanced the antinociceptive effect of the 5-HT agonists 5-methoxy-N,N-dimethyltryptamine (5-MeODMT), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and 5-hydroxytryptophan (5-HTP). This effect was observed after 2, 5 and 8 days in the tail-flick test and after 5 and 8 days in the hot-plate test. However, pretreatment with PCPA or PCA failed to alter the antinociception elicited by the 5-HT agonists, although a tendency towards enhancement of antinociception was found after combined treatment with PCA and PCPA. It is suggested that the injection of 5,7-DHT induces denervation supersensitivity of post-synaptic 5-HT receptors. The lack of such supersensitivity after PCPA-pretreatment which induces similar 5-HT depletion to 5,7-DHT, may suggest that other factors than the absence of 5-HT may contribute to the development of denervation supersensitivity. Alternatively, the three 5-HT depleting agents may produce a qualitatively different reduction of 5-HT.
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PMID:5-HT depletion with 5,7-DHT, PCA and PCPA in mice: differential effects on the sensitivity to 5-MeODMT, 8-OH-DPAT and 5-HTP as measured by two nociceptive tests. 296 56


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