5-HT2A SEROTONIN RECEPTORS IN THE BRAIN OF RATS AND MICE HEREDITARILYPREDISPOSED TO CATALEPSY

Specific binding of [H-3]ketanserin to 5-HT2A serotonin receptor sites in the corpus striatum and frontal cortex and the effect of 5-HT2A an tagonists in rats and mice hereditarily predisposed to catalepsy has b een studied. Cyproheptadine inhibited the expression of inherited cata lepsy in rats and mice, whereas more selective 5-HT2A antagonists, rit anserin and ketanserin, failed to affect the catalepsy. A decrease in [H-3]ketanserin-specific binding site density in the striatum of catal eptic animals compared to their noncataleptic counterparts was found. It was suggested that the decrease in the density of 5-HT2A receptor b inding sites in the striatum represents a result of their downregulati on due to increased serotonergic neurotransmission in the striatum of cataleptic animals.