The effects of manipulation of presynaptic 5-HT nerve terminals on postsynaptic 5-HT1 and 5-HT2 binding sites of the rat brain.

The effects of long-term treatment of rats with alaproclate and amiflamine on the number and kinetics of 5-HT1 and 5-HT2 binding sites were investigated using in vitro receptor binding techniques. Some other studies have reported down-regulatory effects of alaproclate and amiflamine on 5-HT2 binding sites in certain regions of the rat forebrain, but no such effects could be detected in the present study. Induction of a high-affinity binding site for 3H-5-HT after long-term antidepressant treatment, as has been reported elsewhere, was not obtained in the present study. The results are compared to the effects obtained by treatment of rats with para-chloroamphetamine (PCA), which depletes the presynaptic neurons of monoamines. These different types of treatment do not cause any change in the binding properties of the specific 5-HT binding sites. It is thus concluded that such manipulations of the presynaptic 5-HT neurons do not affect the postsynaptic 5-HT1 and 5-HT2 binding sites.