254 Distribution of corticosteroid hormone receptor mRNA in rat brain

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254 Department

Distribution

of corticosteroid

of Anatomy and Neurobiology,

hormone receptor mRNA in rat brain

Kyoto Prefectural University of Medicine, Kyoto, 602, Japan

Takao Ito, Noriyuki Morita, Mitsuhiro Kawata Corticosteroid hormones have been shown to have various effects on the central nervous system. Those effects are mediated through the adrenal steroid receptors; mineralocorticoid receptor (MR) and glucocorticoid receptor (GR). In this study, we investigated the localization of mRNAs of MR and GR in the rat brain’using in situ hybridization histochemistry. Fluorescein-labeled RNA probes were synthesized from cDNA fragments for MR and GR. Probe for GR mRNA was complementary to the fragment in the transcription modulation (TM) domain. Probes for MR mRNA were complementary to the fragment in the TM domain and to the fragment in the ligand binding domain. These two MR probes showed the same distributional pattern of signals. The strong hybridization signals of MR and GR mRNAs were mainly detected in the cerebral cortex and the hippocampal formation. In addition, hybridization signals of MR and GR mRNAs were observed in the brain stem.

255

DISREGULATION OF HEARING ORPHANIN FQ RECEPTOR

ABILITY

IN MICE

LACKING

NOCICEPTIN/

Depts. of Anatomy’, Otolaryngology, Kansai Medical Univ., Osaka 570, Japan*, Dept. of Neurochem., Tokyo Inst. of Psychiat., Tokyo 156, Japan 3, Dept. of Pharmacology, Fat. Med., Univ. of Tokyo, Tokyo 113, Japan4, Dept. of Cell Biology, Cancer Inst., Tokyo 170, Japan5 TAKESHI HOUTANI’, MIYUKI NISH13, KAZUO SATO*, SATORU SAKUMAl, MICHIKO IKEDA’, HIROSHI TAKESHIMA4, TETSUO NODA5, TETSUO SUGIMOTO’ In the G-protein-coupled receptor superfamily, the opioid receptor subfamily is constituted of the three distinct opioid receptors (namely b, p- and K-subtypes) and the receptor for nociceptin (also designat,ed as orphanin FQ). The members of the opioid receptor subfamily were known to mediate a variety of cellular inhibitory effects. The three opioid receptors are known to play central roles in mediating analgesia and many other physiological activities; however, the nociceptin receptor was identified recently and less is known about its physiological roles. Here we report the generation and characterization of mice lacking the nociceptin receptor. The knockout mice showed that the nociceptin system is not essential for regulation of nociception or locomotor activity. On the other hand, we found insufficient recovery of hearing ability from the adaptation to sound exposure in the mutant mice. Thus, the nociceptin system appears to participate in the regulation of the auditory system.

256

NADPH-diaphorase

activity in the paraventricular

Department of Anatomy and Neurobiology, Hirokoji, Kamigyo-ku, Kyoto 602, Japan

Kyoto Prefectural

and supraoptic nuclei in postnatal rat University

of Medicine, Kawaramachi-

YiMu Yang, Hitoshi Ozawa, Kazunari Yuri, Mitsuhiro Kawata Nitric oxide synthase (NOS) was detected in the developing rat brainindicating the possibility of role of NO in the developmental process. In the present study, we studied the development of NADPH-diaphorase (ND) activity, which is identical to NOS, in the hypothalamus of postnatal rats. Intense ND activity in the paraventricular nucleus (PVN) was observed in early postnatal (2, 3 days) rat as in the adult, whereas ND activity in the supraoptic nucleus (SON) was weak in early postnatal days and was increased after postnatal 14 days. The number of ND positive neurons in the PVN showed the tendency to increase with ages postnatally. These results indicate that the developmental pattern of ND activity could be different between the PVN and SON.