Serotonin Reinnervation of the Suprachiasmatic Nucleus by Intrahypothalamic Fetal Raphe Transplants, with Special Reference to Possible Influences of the Target.

摘要: Survival and development of fetal serotonin (5-HT) neurons grafted to various brain areas in adult mammals have been suggested be under host influences. The aim this study was determine whether the suprachiasmatic nucleus hypothalamus (SCN), a region receiving 5-HT input which is one densest most heavily synaptic brain, can actually support transplanted neurons. time course extent reinnervation were therefore investigated with immunocytochemistry rats subjected intraventricular injection 5,7-dihydroxytryptamine subsequent grafting cell suspension mesencephalic raphe ultrastructural features newly formed terminal plexa also examined. Serotonin SCN remained partial up 4 months post-transplantation, no apparent predilection reinnervating fibres for any particular portion nucleus, thus differing from normal innervation both quantitatively qualitatively. This sharp contrast hyperinnervation observed neighbouring such as supraoptic structure normally provided only few fibres, ventral wall third ventricle. graft-derived axons, however, displayed that did not appear different those their counterparts; they re-established defined contacts population. These results may indicate mature specifically lacks trophic factor necessary ingrowth or it represents an inhibitory environment ingrowth. limited ability regrowing axons restore density could related fact these establish relatively high number target region.