4-07 LOCALIZATION OF THE OXYTOCIN RECEPTOR mRNA IN THE RAT BRAIN.

RYOICHI YOSHIMURA. HIROSHI KIYAMA. *TADASHI KIMURA. TOSHIYUKI ARAKI. AND MASAYA TOHYAMA. Department of Anatomy & Neuroscience. and ‘Department of Obstetrics and Gvnecoloav. Osaka c

The expression of oxytocin receptor (OT-R) mRNA in the rat central nervous system was demonstrated by in situ hybridization histochemistry using complementary RNA probe. The wide distribution of OT-R mRNA positive cells was observed not only in the hypothalamus, but also in the various brain regions. The prominent expression of the OT-R mRNA was observed in the anterior olfactory nuclei, layer 213 of the cerebral cortex, the medial preoptic area, the bed nucleus of the stria terminalis, the central nucleus of the amygdaloid complex, supraoptic nucleus, paraventricular nucleus, the ventromedial nucleus of the hypothalamus, supra mammillary nucleus, subiculum, the lateral reticular nucleus, prepositus hypoglossal nucleus, and the dorsal vagal nucleus. Present result coincided well with the binding site of 125l-OTA(125l-d(CH2)5[Tyr(Me)2, Thr4, Tyr(NH#]OVT) in the most regions of the brain. The mis-match problem between the oxytocin containing terminal localization and the receptor localization derived from both present study and previous ligand binding study still remains in some regions such as the anterior olfactory nuclei and the ventromedial nucleus of the hypothalamus. The developmental change of the OT-R mRNA expression will also be demonstrated

4-08 DISTRIBUTION OF PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE (PACAP- -- IMMUNOREACTIVE STRUCTURES IN RAT BRAIN. SHIGEHARU KIMURA,LIPIN LIN,*CHIZUKO

YANAIHARA,**NOBORU YANAIHARA AND YAHE SHIOTANI, Department of Neuroanatomy, Biomedic- al Research Center and *Laboratory of Pharmaceutical Sciences, Osaka University Med- ical School,Suita,Osaka,Japan.**Faculty of Pharmaceutical Sciences, University of- - Shizuoka, Shizuoka,Japan

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Pifditary Adenylate Cyclase Activating-Polypeptide (PACAP) was isolated frorl ovine hypothalamus which stimulated CAMP accumulation in rat anterior pituitary c:ell culture. The peptide was present in the two bioactive amidated forms,PACAP38 and PA- CAP27 (38 and 27 amino acid residues, respectively). Using the antibody to PACAP: (R08311, we demonstrated the immunoreactive cells not only In forebrain regions bin- cludlnq supraoptic nucleus, paraventrlcular nucleus, perlventricular nucleus and suprachiasmatic nucleus, but also in brainstem particularly In trigeminal mesenccs- phalic nucleus. Immunoreactive fibers were observed in median eminence, poster:o:- pituitary gland and trigeminal nerves. This finding :suqgests possible role of PACAP as a ncurotransmitter or neuromodulator, in addition to hypothalamic hormone.

4-09 DIABETES INDUCES REDUCTION OF CALCITONIN GENE-REL T D PEPTIDE IMMUNOREACTIVE NEURONS

3 N VITRO. KAZUNORI SANGO"'. LNAOSHI H;::::'; BIDENOR HORIEl, SHUN-ICHI TANAKA . SHUJI INOUEC. YUTARO WMlJRA _ AND TO- TAKENAKA', DeDartments of Physiology' and Internal Medicine . School of Medicine, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama 236, Japan

The neuropeptides such as substance P (SP), calcitonin gene-related peptide (CGRP), somatostatin (SOM) and vasoactive intestinal polypeptide (VIP) have been thought to play an essential role in the function of sensory neurons. In the present study, the expressions of these peptides in dorsal root ganglion neurons from streptozotocin-diabetic mice were analyzed with immunohistochemistry. We couldn't. see any significant difference in the ratios of SP. SOM. or VIP-positive neurons between the diabetic and normal mice. In contrast. however, the ratios (15- 20 X) of CGRP-positive neurons in the diabetic mice were significantly lower than those (45-60 X) in the normal mice. The results show that diabetes causes the depletion of CGRP in sensory neurons, and this depletion may be closely related to the development of diabetic neuropathy.