title: Naloxone-induced changes in tachykinin NK3 receptor modulation of experimental anxiety in mice.
abstract: This study investigates the influence of naloxone, an opioid antagonist, upon the effects of drugs acting on tachykinin NK3 receptor in the elevated plus-maze test. Mice were intracerebroventricularly (i.c.v.) injected either with vehicle, 10 pmol of senktide, an NK3 agonist, or 100 pmol of [Trp7beta-Ala8]NKA(4-10) or SR142801, NK3 antagonists. Senktide alone significantly increased the frequency of entries and the time spent in open arms, an anxiolytic-like effect, whereas the NK3 antagonists alone showed no effect at the dose used. Naloxone alone did not alter the behavior of the animals on the plus-maze apparatus. Nevertheless, animals pretreated with naloxone (2 mg/kg, i.p.) showed an increase in senktide's anxiolytic-like effect and a similar profile of action for [Trp7beta-Ala8]NKA(4-10), but not for SR142801, which presented an anxiogenic-like effect. Altogether, these findings indicate a putative neurokinin-opioid relationship in the modulation of experimental anxiety in mice.
authors.affiliation: Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianópolis, Brazil.
authors.forename: S J
authors.initials: SJ
authors.lastname: Ribeiro
authors.forename: T C
authors.initials: TC
authors.lastname: De Lima
mesh_terms: D000818:Animals; D001007:Anxiety / Q000378:metabolism / Q000503:physiopathology*; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051379:Mice; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D018042:Receptors, Neurokinin-3 / Q000819:agonists / Q000187:drug effects*
chemical_list: D009292:Narcotic Antagonists; D018042:Receptors, Neurokinin-3; D009270:Naloxone