Effects of apomorphine and clonidine on the cerebral cholinergic system
Herman, Z.S.; Zieliński, M.; Kmieciak-Kołada, K.; Kozok, J.; Bień, E.; Plech, A.; Sokoła, A.; Drybański, A.
Polish Journal of Pharmacology and Pharmacy 29(6): 619-628
1977
ISSN/ISBN: 0301-0244 PMID: 600861 Document Number: 123810
The influence of several doses of apomorphine (AP) and clonidine (CL) on the choline acetyltransferase (CAT) and acetylcholine esterase (AChE) activity and on the acetylcholine (ACh) level in the brain of mice was studied. The behavior of animals under influence of mentioned agents was examined. AP (1 or 5 mg/kg s.c.) decreased AChE activity, increased the ACh level and has not changed CAT activity. Haloperidol abolished effect of AP on AChE activity. AP increased locomotor activity (1 or 5 mg/kg s.c.) or caused stereotypy (50 mg/kg s.c.). CL in some doses decreased CAT activity, increased ACh level and has not changed AChE activity. The decrease of CAT activity produced by low doses (1 or 5 .mu.g/kg) of CL was prevented by phenoxybenzamine or propranolol. CL in high doses (0.1 or 1 mg/kg) depressed locomotor activity of mice, and in very low dose (0.1 .mu.g/kg) stimulated this type of behavior. Stimulation of catecholaminergic receptor of brain elicits a cholinergic counter action. Stimulation of central dopaminergic or noradrenergic receptors causes different responses of key metabolic enzymes of the central cholinergic system. Small doses of CL maybe more useful than higher ones, as an experimental tool for stimulation of central noradrenergic receptors.