INCREASES IN CEREBRAL BLOOD FLOW INDUCED BY NOCI- CEPTIVE S$$MULATION T. Adachi ment Tokyo Metropolitan Institute of Gerontrogy and Department of Anesthesia2 Tokyo Metropoli- tan Geriatric Hospital, Itabashi, Tokyo, Japan

GREEN Mon-Tues

AIM OF INVESTIGATION: This study was undertaken to investigate the effect of somatosensory stimulation on local cerebral cortical blood flow (CBF). METHODS: In halothane-anesthetized artificially ventilated rats, CBF was

measured continuously by laser Doppler flowmetry. Nociceptive (pinching) and non-nociceptive (brushing) somatosensory stimulation were delivered to various sites of the body and the systemic arterial blood pressure (BP) and CBF changes were recorded. In some rats, the responses of CBF to forepaw pinching were compared before and after spinal transection between 1st h 2nd thoracic vertebrae. RESULTS: Pinching of face, forepaw, hindpaw and tail produced signifi-

cant increases in CBF in various cortices. Pinching of neck and back or brushing of any sites produced no significant changes in CBF. Increases in CBF was always accompanied by increases in BP. After spinal transection, the magnitude of increases in CBF induced by forepaw pinching did not change, but that of BP was reduced significantly.

CONCLUSION: Nociceptive somatosensory stimulation causes CBF increases even under halothane anesthesia, and the increase cannot be fully attribut- ed to passive CBF increases in CBF due to BP elevation. There may be active vasodilatation induced by nociceptive somatosensory stimulation.

BRAIN STEM SIX NEUROTRANSMITTERS PROJECTIONS TO THE NUCLEUS RAPHE HAGNUS. Tisneheng Fan, Xisnxiang Chu: Xueguo Zhang*and Tianhen Kong Dept. of Anatomy, Henan Medical Univereity, Ehengshou, Henan, People's Republic of China

AIH OF INVESTIGATION: The nucleus raphe magnus(NRM) is one of I Poster 88 i GREEN Non-Tues' Exhibit Hall Abs No 131

importent position in electroacupuncture(EA) analgesia. Though the origin of afferent fibera to NRN were studied during the past few years in our lab.,the neurotransmitters in these fibers have not been demonatrated. METHODS: We utilized the'combination of HRP with imaunohietochemical technique.

Experiments were performed on 17 adult rats. HRP were injected into NRN. After 24h, the animals were treated with colchicine injected intraventricularly. The animals were performed at 24 h after the colchicine injected. microtome and proceaaed with TMB-DAB-CoC12 method,

Sectiona were cut on a freezing then 5-HT, SP, H-ENK, L-EN%, B-EP

and SRIF labeled cella were demonstrated with PAP method. RESULTS: I) The cells projections to NRN, which were labeled with 5-HT, were found

in ventral of central gray(CG), doreal raphe nucleua(DR), superior central nucleue (SW), raphe pontis nncleue(RPN), ravhe obscurus nucleua(RON), raphe pallidus nucleus (RPN), gigantocellular reticular nuclens(GRIV) and paramedial reticular nucleus(PRN); 2) The cells labeled with SP and projected to NRN were found in CG, DR and RON; 3) The cells projections to NRR , which were labeled with ENK, were found in CG, DR, GRN, vestibular nucleus and solitary tract nucleus; 4) The cells labeled with SRIF and a few of double labeled cells were found in CC and DR. CONCLUSION: The DreaeDt investigation demonetrat that NRM is complex cells group,

it not only receive the fibers of 5-HT but also reqeive the fiber8 in whioh contain other five peptidergic neurotranemitters. position in EA analgesia,

This study suggested NRN, one of impordent was mediated by at least six kinds of neurotransmitters in

different afferent fibera.