Reinnervation of serotonin fibers in the denervated rat subcommissural organ by fetal raphe transplants. An immunohistochemical study.

The ability of axonal outgrowth of serotonin neurons in the implanted brain tissue of subcommissural organ (SCO) was immunohistochemically studied. The serotonin neuron system of the experimental rats was completely destroyed by the intraventricular injection of 5,6-dihydroxytryptamine. The raphe region of normal fetal rats was implanted into the caudal part of the third ventricle of the neurotoxic drug pretreated rats. The host brain was examined 3 months after transplantation. The numerous serotonin fibers were distributed in the SCO and periventricular region of the third ventricle of the host brain. The outgrowing serotonin fibers from the raphe transplant seemed to innervate the SCO with the target specificity.