[Mechanism of action of clonidine in the forced-swimming test in mice].
Clonidine displays immobility-reducing effects in the mouse swimming model at doses (0.06-16 mg/kg IP) which decrease spontaneous motility. Tricyclic antidepressants evoke a similar dissociation in motor activity. The immobility-reducing effect of clonidine (1 mg/kg at 30 min pretesting) was reversed by yohimbine (4 mg/kg) but was unaffected by prazosin (2 mg/kg) or alpha-methyl-paratyrosine (100 mg/kg), and was enhanced by reserpine (2.5 mg/kg). Mediation by alpha-2 postjunctional receptors was thus suggested. However, two 5-HT receptor blockers--methysergide (2 mg/kg) and ketanserin (8 mg/kg)--increased this effect of clonidine whereas the non selective agonist 5-MeODMT (1 mg/kg) reduced clonidine action. Conversely, pretreatment with a subthreshold dose of clonidine (0.06 mg/kg at 45 min pretesting) made effective subthreshold doses of three 5-HT uptake inhibitors (citalopram 2 mg/kg, indalpine and fluvoxamine 4 mg/kg) and of the 5-HT1 receptor agonist 8-OH-DPAT (0.5 mg/kg). According to these data, the mouse swimming model would trigger functional relationships between central alpha-noradrenergic and serotonergic mechanisms.
Malinge
M
M
Laboratoire de Pharmacologie, Faculté de Médecine, Nantes.
Colombel
M C
MC
Bourin
M
M
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003000:Clonidine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004347:Drug Interactions; D008297:Male; D051379:Mice; D011224:Prazosin / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D013550:Swimming; D015016:Yohimbine / Q000494:pharmacology
D012702:Serotonin Antagonists; D015016:Yohimbine; D012110:Reserpine; D003000:Clonidine; D011224:Prazosin
Mécanisme(s) d'action de la clonidine dans le test de la nage forcée chez la souris.