The effects of acute and repeated treatment with salbutamol, a beta-adrenoceptor agonist, on clonidine-induced hypoactivity in rats.
A dose-dependent decrease in exploratory activity of naive rats was observed after 5-20 mg/kg i.p. of salbutamol. This effect was antagonized by the pretreatment with propranolol and yohimbine. Furthermore, in a single dose of mg/kg salbutamol increased clonidine-induced hypoactivity. By contrast to acute effects, repetitive administration of salbutamol (5 mg/kg twice daily for 10 days) failed to change exploratory activity of rats and abolished the clonidine-induced hypoactivity. The results demonstrate differences in the acute and chronic effects of salbutamol on behaviour which may indicate changes in the sensitivity of adrenergic pre- as well as postsynaptic alpha-adrenoceptors. Tentatively, the results could be explained by development of alpha2-adrenoceptor subsensitivity and the involvement of beta-adrenoceptors in the regulation of their activity.
D000420:Albuterol / Q000008:administration & dosage*; D000818:Animals; D003000:Clonidine / Q000008:administration & dosage*; D003891:Desipramine / Q000008:administration & dosage; D004347:Drug Interactions; D005106:Exploratory Behavior / Q000187:drug effects*; D005473:Fluoxetine / Q000008:administration & dosage; D007099:Imipramine / Q000008:administration & dosage; D008297:Male; D011433:Propranolol / Q000008:administration & dosage; D051381:Rats; D011919:Rats, Inbred Strains; D015016:Yohimbine / Q000008:administration & dosage
D005473:Fluoxetine; D015016:Yohimbine; D011433:Propranolol; D003000:Clonidine; D007099:Imipramine; D000420:Albuterol; D003891:Desipramine