[Effects of muscimol on aggressive behaviors induced by clonidine in mice].

Article date: 1989/9/1

PubMed ID: 2557712

Journal name: Yakubutsu, seishin, kodo = Japanese journal of psychopharmacology (ISSN: 0285-5313)


A behavioral study was carried out to clarify a relationship between the GABAergic and purinergic central system in aggressive behaviors induced by clonidine in mice. Mice administered a high dose of clonidine (20 mg/kg, i.p.) exhibited aggressive behaviors such as biting and attacking. These behaviors are inhibited by L-PIA (N6-L-phenylisopropyl adenosine) and stimulated by caffeine, which suggest that a blockade of adenosine receptors is involved in these behaviors. Muscimol (0.5-2 mg/kg, i.p.), a GABA-a receptor agonist, not only markedly potentiated clonidine (20 mg/kg i.p.)-induced aggressive behaviors but also elicited characteristic behaviors such as gnawing, reinforced irritability, and self-mutilation. Bicuculline (1, 2 mg/kg, i.p.), a GABA-a receptor antagonist, or picrotoxin (1 mg/kg, i.p.), a chloride channel blocker, did not significantly affect clonidine (20 mg/kg, i.p.)-induced aggressive behaviors. The potentiating effects of muscimol (0.5, 1 mg/kg, i.p.) on clonidine-induced aggressive behaviors were antagonized by bicuculline (1, 2 mg/kg, i.p.), but not affected significantly by picrotoxin (1 mg/kg, i.p.). L-PIA (0.2 mg/kg, i.p.) reduced clonidine-induced aggressive behaviors and also reversed the potentiating effects of muscimol. Stereotyped gnawing behaviors induced by combined treatment of muscimol (0.5, 1 mg/kg, i.p.) and clonidine (20 mg/kg, i.p.) were not affected by bicuculline (2 mg/kg, i.p.). The results suggest that the potentiating effects of muscimol on clonidine-induced aggressive behaviors may be induced via the stimulation of GABA-a receptors, although not necessarily associated with chloride channel functions, and may involve certain interactions between the stimulation of GABA-a receptors and the inhibition of adenosine receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Author List: Kaneyuki H

Publication Types: English Abstract; Journal Article

Substances mentioned in the article: Receptors, GABA-A; Picrotoxin; Muscimol; Clonidine; Bicuculline;

Mesh terms: Aggression/drug effects; Animals; Behavior, Animal/drug effects; Bicuculline/pharmacology; Clonidine/pharmacology; Dose-Response Relationship, Drug; Drug Synergism; Male; Mice; Muscimol/antagonists & inhibitors; Picrotoxin/pharmacology; Receptors, GABA-A/physiology;

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