5-HT2A serotonin receptors in the brain of rats and mice hereditarily predisposed to catalepsy.

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