NEURONAL LABELING IN THE RAT-BRAIN AND SPINAL-CORD FROM THE OVARY USING VIRAL TRANSNEURONAL TRACING TECHNIQUE

In the present investigations the viral transneuronal labeling method, which is able to reveal hierarchial chains of central nervous system (CNS) neurons, was applied to identify sites in the CNS connected with the ovary and presumably involved in the control of ovarian functions . Pseudorabies virus was injected into the ovaries of rats and a few d ays later (at various times after the injection) the spinal cord and b rain were examined for virus-infected neurons from the ovary. The viru s-labeled nerve cells were identified by immunocytochemistry using pol yclonal antiviral antibody. Virus-labeled neurons were detected both i n the spinal cord and the brain. In the spinal cord such elements were observed in the intermediolateral cell column, in the dorsal horn clo se to the marginal zone and in the central autonomic nucleus. In the m edulla oblongata and pens, neurons of several nuclei and cell groups ( area postrema, nucleus of the solitary tract, dorsal vagal complex, nu cleus ambiguus, paragigantocellular nucleus, parapyramidal nucleus, A1 , A5 and A7 cell groups, caudal raphe nuclei, locus ceruleus, subcerul eus nucleus, Barrington's nucleus, Kolliker-Fuse nucleus) were found t o be transneuronally labeled. In the mesencephalon, the ventrolateral part of the periaqueductal gray matter contained virus-labeled neurons . In the diencephalon, a very intensive cell body labeling was observe d in the hypothalamic paraventricular nucleus and a few virus-infected neurons could be detected in the lateral and dorsal hypothalamus, in the arcuate nucleus, zona incerta, perifornical area and in the anteri or hypothalamus. Concerning the telencephalic structures, virus-labele d cells were found in the bed nucleus of the stria terminalis and in t he central amygdala nucleus. These findings provide the first neuromor phological evidence for the existence of a multisynaptic neuronal path way between the ovary and the CNS, and give a detailed account of the structures involved in this pathway.