Article date: 1991/1/1
PubMed ID: 1708148
Journal name: Pharmacology, biochemistry, and behavior (ISSN: 0091-3057)
Microinjection and lesion studies have implicated the midbrain dorsal (DR) and median raphe (MR) nuclei in behavioral arousal. This behavioral state is manifested as locomotor hyperactivity, hyperphagia, hyperdipsia and increases in plasma corticosteroid release. Intra-midbrain raphe injections of the GABAA agonist muscimol elicit this behavioral activation. We have demonstrated that similar infusions of tachykinins produce locomotor hyperactivity through activation of neurokinin-3 (NK-3) receptors located on serotonin cell bodies. The purpose of the present study was to determine the effects of intra-MR and DR infusions of senktide, an NK-3 agonist, on food and water consumption in nondeprived rats. Male Sprague-Dawley rats were implanted with indwelling intra-MR or intra-DR cannula. Infusions of muscimol (25 ng/0.5 microliters) into the MR increased water intake, while MR and DR infusions increased food consumption. In contrast, intra-MR injections of senktide decreased water intake and intra-MR and DR injections decreased food intake. The results suggest that the behavioral states induced by muscimol and neurokinin infusions into the raphe are distinct and that raphe/neurokinin pathways are involved in consummatory mechanisms.
Author List: Paris J M, Mitsushio H, Lorens S A
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Peptide Fragments; Receptors, Neurokinin-2; Receptors, Neurotransmitter; senktide; Muscimol; Substance P;
Mesh terms: Animals; Dose-Response Relationship, Drug; Drinking/drug effects; Eating/drug effects; Male; Mesencephalon; Microinjections; Motor Activity/drug effects; Muscimol/pharmacology; Peptide Fragments/administration & dosage; Raphe Nuclei; Rats; Rats, Inbred Strains; Receptors, Neurokinin-2; Receptors, Neurotransmitter/drug effects; Substance P/administration & dosage;