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Somatic sensory regulation of hypothalamic secretion of corticotropin-releasing hormone
S67
HYPOTHALAMIslSECRETION SOMATIC SENSORY REGULATION OF OF CO~~ICOTROPINiRELEASING HORMON$j Hotta,H. , Kurosawa,M. , Sato,A. and Sumitomo,T. 1; Dept. of Physiol., Tokyo Metropol. Inst. of Geronto1., Tokyo, 2; Dept. of Physiol.,Nara Medical School, Nara,3; Dept. of Medicine, Tokyo Women's Medical College, Tokyo, Japan.
Poster a5 GREENNon-Tues ExhibitHall Abs No 128 m
AIM OF INVESTIGATION: Mechanism of modulation of various autonomic functions by somatic noci eptive afferent have been studied in our laboratory in The purpose of the present study was to examine anesthetized animals E . responses of hypothalamic secretion of corticotropin-releasing hormone (CRH) to either noxious or innocuous mechanical stimulation of skin. METHODS: Male Wistar rats were anesthetized with halothane (1.0%) and their respiration was maintained artificially by a respirator. Hypothalamo-hypophysial-portal blood was collected continuously to calculate the secretion rate of CRH by measuring CRH concentration in plasma using radioimmunoassay method and by measuring the plasma flow rate, before, during and after the cutaneous stimulation. RESULTS: It was found that noxious stimulation of hindpaws for 20 min by pinching with a surgical clamps produced an increase (about 50% increase) in secretion of CRH whereas innocuous stimulation of abdomen by brushing with a toothbrush did not influence the secretion. CONCLUSION: In anesthetized rats, noxious mechanical stimulation of hindpaws produced an increase in secretion of CRH from hypothalamus. 1; Sato, A.and Schmidt, R.F. (1987) The modulation of visceral functions by somatic afferent activity. Jap. J. Physiol., 37: l-17.
EFFECTS OF SOMATOSENSORY STIMULI ON THE NEURONAL ACTIVITY IN THEeNUCLEUS BASALIS OF MEYNERT (NBM). T. Akaishi , Y. Saeki , A. Sato, Department of PhysiolTokyo Metropolitan Institute of Gerontrogy, Itaogy bashi, Tokyo, Japan
Poster 86 GREEN Mon-Tues Exhibit Hall Abs No
129 I
AIM OF INVESTIGATION: The stimulation of the nucleus basaiis pf Meynert (NBM) increases local cerebral blood flow in the sensory cortex . Somatosensory stimulation also induces similar effects in blood flow of sensory cortex. The present study was undertaken to determine the electrical activity of NBM neurons following somatosensory stimulation. METHODS: In urethan-anesthetized artificially ventilated rats, electrical activity of NBM neuron antidromically activated by stimulation of anterior parietal cortex was recorded. Nociceptive (pinching) and nonnociceptive (brushing) stimulation were delivered to the face, forelimbs, back, and hindlimbs. RESULTS: In most NBM neurons tested, non-nociceptive brushing stimulation to the face, forelimbs, back, or hindlimbs showed non-significant changes in their firing rates. In contrast, nociceptive pinching stimulation to the forepaw or hindpaw induced a significant increase in discharge frequency compared to the control level. Pinching of the face or back had significant effect on the neuronal activity in about half of the neurons tested. CONCLUSION: NBM neurons projecting their axons to the anterior parietal cortex are responsive to nociceptove somatosensory inputs. It is suggested that NBM neurons control the vasodilatory mechanism in the sensory cortex of the rat. 1; Biesold, D. et al. (1989) Stimulation of the nucleus basalis of Meynert increases cerebral cortical blood flow in rats. Neurosci. Lett., 98:39-44.
HYPOTHALAMIslSECRETION SOMATIC SENSORY REGULATION OF OF CO~~ICOTROPINiRELEASING HORMON$j Hotta,H. , Kurosawa,M. , Sato,A. and Sumitomo,T. 1; Dept. of Physiol., Tokyo Metropol. Inst. of Geronto1., Tokyo, 2; Dept. of Physiol.,Nara Medical School, Nara,3; Dept. of Medicine, Tokyo Women's Medical College, Tokyo, Japan.
Poster a5 GREENNon-Tues ExhibitHall Abs No 128 m
AIM OF INVESTIGATION: Mechanism of modulation of various autonomic functions by somatic noci eptive afferent have been studied in our laboratory in The purpose of the present study was to examine anesthetized animals E . responses of hypothalamic secretion of corticotropin-releasing hormone (CRH) to either noxious or innocuous mechanical stimulation of skin. METHODS: Male Wistar rats were anesthetized with halothane (1.0%) and their respiration was maintained artificially by a respirator. Hypothalamo-hypophysial-portal blood was collected continuously to calculate the secretion rate of CRH by measuring CRH concentration in plasma using radioimmunoassay method and by measuring the plasma flow rate, before, during and after the cutaneous stimulation. RESULTS: It was found that noxious stimulation of hindpaws for 20 min by pinching with a surgical clamps produced an increase (about 50% increase) in secretion of CRH whereas innocuous stimulation of abdomen by brushing with a toothbrush did not influence the secretion. CONCLUSION: In anesthetized rats, noxious mechanical stimulation of hindpaws produced an increase in secretion of CRH from hypothalamus. 1; Sato, A.and Schmidt, R.F. (1987) The modulation of visceral functions by somatic afferent activity. Jap. J. Physiol., 37: l-17.
EFFECTS OF SOMATOSENSORY STIMULI ON THE NEURONAL ACTIVITY IN THEeNUCLEUS BASALIS OF MEYNERT (NBM). T. Akaishi , Y. Saeki , A. Sato, Department of PhysiolTokyo Metropolitan Institute of Gerontrogy, Itaogy bashi, Tokyo, Japan
Poster 86 GREEN Mon-Tues Exhibit Hall Abs No
129 I
AIM OF INVESTIGATION: The stimulation of the nucleus basaiis pf Meynert (NBM) increases local cerebral blood flow in the sensory cortex . Somatosensory stimulation also induces similar effects in blood flow of sensory cortex. The present study was undertaken to determine the electrical activity of NBM neurons following somatosensory stimulation. METHODS: In urethan-anesthetized artificially ventilated rats, electrical activity of NBM neuron antidromically activated by stimulation of anterior parietal cortex was recorded. Nociceptive (pinching) and nonnociceptive (brushing) stimulation were delivered to the face, forelimbs, back, and hindlimbs. RESULTS: In most NBM neurons tested, non-nociceptive brushing stimulation to the face, forelimbs, back, or hindlimbs showed non-significant changes in their firing rates. In contrast, nociceptive pinching stimulation to the forepaw or hindpaw induced a significant increase in discharge frequency compared to the control level. Pinching of the face or back had significant effect on the neuronal activity in about half of the neurons tested. CONCLUSION: NBM neurons projecting their axons to the anterior parietal cortex are responsive to nociceptove somatosensory inputs. It is suggested that NBM neurons control the vasodilatory mechanism in the sensory cortex of the rat. 1; Biesold, D. et al. (1989) Stimulation of the nucleus basalis of Meynert increases cerebral cortical blood flow in rats. Neurosci. Lett., 98:39-44.