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Serotonergic (5-HT) neuronal pathways regulate the release of adrenocorticotropin hormone (ACTH) from the pituitary gland probably through the action of hypothalamic corticotropin-releasing hormone (CRH). 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a selective 5-HT1A receptor agonist, dose dependently (0.016-3 mg/kg s.c.) increased rat plasma ACTH(More)
The purpose of the present study was to examine the dose-response relationship and the maximum time for which effective therapy could be delayed for the N-methyl-D-aspartate antagonist dizocilpine (MK-801) as a neuroprotective agent in a permanent focal ischaemia model in the rat. The ED50 for dizocilpine in the amelioration of cortical damage in this model(More)
1. An acute model of focal ischaemia, which involves permanent occlusion of the middle cerebral artery of the rat with 4 h survival, was used to find the minimum effective plasma concentration of dizocilpine (MK-801) and to determine its dose-effect relationship. 2. MK-801 was administered at the time of occlusion and was given as an i.v. bolus followed by(More)
The effects of the serotonin agonist MK-212, on rat plasma ACTH were examined. MK-212 significantly increased plasma ACTH levels, and this effect was blocked by the 5-HT1C antagonists mesulergine and metergoline but not by spiperone, ketanserin, or (-)-pindolol. The results suggest that MK-212 activates the 5-HT1C receptor subtype to increase ACTH.
Administration of the muscarinic antagonist scopolamine has been proposed as a pharmacological model for Alzheimer's disease. We have attempted to characterize the cognitive deficits produced by the administration of scopolamine (0.2 and 0.4 mg intra muscularly) to normal volunteers. We have also demonstrated reversal of these deficits by the cholinesterase(More)
Chronic administration of clorgyline or ritanserin to adult rats for 28 days followed by a 3 day drug-free period results in a significant decrease in 5HT2 receptor number (Bmax) in rat frontal cortex from 315.23 +/- 10.72 fmol/mg protein to 249.63 +/- 13.99 fmol/mg protein and 222.55 +/- 17.17 fmol/mg protein, respectively. On rat blood platelets,(More)
The transient impairments of memory produced by the muscarinic antagonist scopolamine have been adopted as a pharmacological model of Alzheimer-type dementia in normal volunteers. In this study we examined the effects of chronic (72 h) transdermal administration of scopolamine on memory, attention, sedation and visual function. The transdermal patches(More)
Various putative agonists of the 5-HT1A receptor subtype induce feeding in rats, probably by activating raphé somatodendritic 5-HT autoreceptors. These drugs also produce a marked increase in plasma concentrations of corticotropin (ACTH). In the present experiment we attempted to localize the site of action of 5-HT1A agonists on the secretion of ACTH and(More)
We have assayed several phenylalkylamine and indolealkylamine hallucinogens, as well as structurally similar nonhallucinogens, for their effect on human platelet shape change, a physiological model for the central serotonergic 5-HT2 receptor. The hallucinogenic drugs lysergic acid diethylamide (LSD-25), N,N-dimethyltryptamine (N,N-DMT),(More)
Cholinergic replacement therapy for Alzheimer's disease using existing cholinesterase inhibitors is compromised by short duration, meagre benefits restricted to subgroups of patients, and peripheral toxicity. Heptyl physostigmine is a lipophilic carbamate derivative of physostigmine. In rhesus monkeys, heptyl physostigmine (0.2-0.9 mg/kg i.m.) fully(More)