POSTLESION UP-REGULATION OF 5-HT1B BINDING-SITES IN THE SUPRACHIASMATIC NUCLEUS MAY BE REVERSED AFTER SPONTANEOUS OR GRAFT-INDUCED SEROTONIN REINNERVATION

We have previously reported that selective axotomy of serotoninergic n eurons produced by an intraventricular injection of 5,7-dihydroxytrypt amine is followed by an increase in 5-HT1B binding sites in the suprac hiasmatic nucleus of the hypothalamus. This post-lesion up-regulation is shown here to be spontaneously reversed after long-term survival in spite of an incomplete reinnervation of the nucleus. Recovery may be accelerated by fetal raphe transplants that produce more rapid reinner vation. (C) 1998 Elsevier Science B.V.