EFFECTS OF DRUGS AFFECTING SEROTONERGIC SYSTEM ON ACTIVITIES OF CENTRAL DOPAMINERGIC AND SEROTONERGIC SYSTEMS IN RATS

Abstract

Publisher Summary This chapter discusses a study to examine the effects of drugs affecting serotonergic system on the activities of central dopaminergic and serotonergic systems in rats. The study investigated the action of (1) 5-HT-lytics including cyproheptadine (CP), danitracen, metergoline, and methysergide and (2) 5-HT-mimetics including quipazine (QP) and m-chlorophenylpiperazine (CPP) on the activity of DA-ergic and 5-HT-ergic systems in the rat brain, assessing it from the accumulation of DOPA and 5-HTP in the brain after the inhibition of cerebral decarboxylase with 100 mg/kg of p-hydroxybenzylhydrazine. The results seem to corroborate the notion that QP affects both 5-HT and DA receptors but suggest that the action of CPP on 5-HT-ergic system is more specific. They also indicate that the stimulation of 5-HT-ergic system leads to a delayed depression of catecholaminergic neurons, reflected by diminished activity of tyrosine hydroxylase in the brain. The fact that only some effects of 5-HT-mimetics (behavioral and the action on DOPA accumulation) are inhibited by 5-HT-lytics suggests the existence of two types of 5-HT receptors of which only one, most probably postsynaptic, is affected by 5-HT-lytics.