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6. Neuropeptides

601 SYNPTIC INTERACTION BETWEEN GALANIN NERVE AFFERENTS AND CHOLINERGIC NEURONS IN THE INTERMEDIOLATERAL

NUCLEUS OF THE RAT LUMBOSACRAL SPINAL CORD. TETSUJI OHMACHI AND HIROSHI TAKAGI, 1st. Dept. of Anatoay. Osaka City Univ. Med. Sch.. Asahiuachi. Abeno-ku. Osaka, 545 Japan

Iaaunoelectron microscopy cabined with confocal microscopy was carried out to examine whether cholinergic neurons make synaptic contacts with galanin (GAL) afferents in the intermiiolateral nucleus of the rat

lumbosacralspinal cord. The cholinergic neurons were frequently found to receive synaptic inputs from GAL axon

terminals. These findings suggest that GAL afferents may affect the activity of cholinergic parasympathetic

preganglionic neurons.

602 PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE(PACAP) IMMUNOREACTIVE NEURONS IN THE TRIGEMINAL GANGLION IN RATS. YOSHIMI OHSHIGE, SHIGEHARU

KIMURA, YAHE SHIOTANI AND CHIZUKO YANAIHARA*, Dept. of Neuroanat., Biomedical Res. Center and Laboratory of Pharmaceutical Science*, Osaka Univ. Med. School, 2-2, Yamadaoka, Suita, Osaka 565 Japan.

PACAP is a novel neuropeptide with 38 or 27 amino acid residues, isolated from the ovine hypothalamus. We previously reported immunolocalization of PACAP in the hypothalamus-pituitary system and adrenal medulla. In this study, we ex- amined PACAP-immunoreactive structures in the trigeminal ganglion. Male adult rats were perfused with Zamboni's solution under pentobarbital anesthesia and cryostat sections of the trigeminal ganglion were immunostained with a spesific antiserum to PACAP 38 (R0831). PACAP immunoreactivity was observed in some neu- rons and nerve fibers. PACAP-neurons were round or oval and large in size, about 45-50 pm in diameter, and nerve fibers were thick. In order to clarify the rela- tionship between the PACAP- and SP-neurons, or PACAP- and CGRP-neurons, adjacent sections were immunostained with antisera to SP or CGRP, respectively. SP- or CGRP-neurons were smaller in size than PACAP-neurons, and SP-or CGRP-fibers were thinner than PACAP-fibers. The collocalization of PACAP and SP, or PACAP and CGRP in a single neuron was not observed.