Effects of propranolol on the locomotor stimulation induced by activation of postsynaptic catecholamine receptors.
The present study was undertaken in order to clarify the possible involvement of a central beta-adrenoceptor mediated action on the stimulation of locomotor activity by the dopamine agonist apomorphine and the noradrenergic agonist clonidine. The effect of pretreatment with various doses of d-and dl-propranolol on apomorphine- and apomorphine plus clonidine-induced locomotor stimulation in reserpinized mice was measured in photocell activity chambers. Pretreatment with dl-propranolol prolonged the duration of apomorphine-induced locomotor stimulation without affecting the maximal level of activity. A similar tendency was seen after pretreatment with the d-form of propranolol, which has a much lower beta-receptor blocking activity. The potentiation by clonidine of the apomorphine-induced locomotor stimulation in reserpinized mice was dose-dependently reduced by pretreatment with dl-propranolol whereas d-propranolol was found to be ineffective. The results indicate that central beta-receptor mechanisms might be involved in the apomorphine plus clonidine-induced locomotor stimulation of reserpinized mice.
D000818:Animals; D001058:Apomorphine / Q000378:metabolism / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D003000:Clonidine / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects*; D011433:Propranolol / Q000494:pharmacology*; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012110:Reserpine / Q000494:pharmacology; D013237:Stereoisomerism
D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D012110:Reserpine; D011433:Propranolol; D003000:Clonidine; D001058:Apomorphine