CNS CELL GROUPS PROJECTING TO PANCREATIC PARASYMPATHETIC PREGANGLIONIC NEURONS

The CNS cell groups that project to the pancreatic parasympathetic pre ganglionic neurons were identified by the viral retrograde transneuron al labeling method. Pseudorabies virus (PRV) was injected into the pan creas of C8 spinal rats and after 6 days survival, the animals were pe rfused and their brains processed for immunohistochemical detection of PRV. Parasympathetic preganglionic neurons of the dorsal vagal nucleu s were retrogradely labeled with PRV. Several CNS cell groups consiste ntly contained transneuronally labeled neurons. In the medulla oblonga ta, labeled neurons were found in the nucleus tractus solitarius. area postrema, paratrigeminal nucleus, lateral paragigantocellular reticul ar nucleus, raphe pallidus and obscurus nuclei, C3 region and scattere d cells in the ventral medullary reticular formation. In the pons, the A5 cell group, Barrington's nucleus and the subcoeruleus region conta ined labeled neurons. Only an occasional labeled cell was identified i n the parabrachial nucleus. In the midbrain, almost no labeling was fo und except for an occasional neuron in the central gray matter. In the diencephalon, labeling was found in the paraventricular hypothalamic nucleus (PVN) as well as in the lateral hypothalamic nucleus at two le vels (one at the level of the PVN and the other at the level of the su bthalamic nucleus). In addition, the perifornical and dorsal hypothala mic nuclei contained labeled neurons. A few cells were found in the pe ripheral part of the dorsomedial hypothalamic nucleus. No labeling was seen in the ventromedial hypothalamic nucleus. In the telencephalon, the central amygdaloid nucleus and the bed nucleus of the stria termin alis were labeled.