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2126 Different thermal dependency of cutaneous sympathetic outflow to the glabrous and hairy skin in humans
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2124
TRANSIENT CttANGES OF N E T W O R K ACTIVITY IN CULTURED CORTICAL NEURONS INDUCED BY Mg2+and APV EISAKII MAEDA 1, IIIIGtt P.C.ROBINSON ~, YOICItlRO KIIRODA 3 AND AI
21 25
L O N G - L A S T I N G P O T E N T I A T I O N A T T H E C E N T R A L I N H I B I T O R Y CONNECTIONS STUDIED BY UNITARY POSTSYNAPTIC POTENTIAL. CHIEKO SUMA, YUSUKE MURAYAMA and YOICHI ODA, Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Toyonaka, Osaka 560, Japan. Long-Term Potentiation(LTP) of inhibitor)' connection has been reported recently in the goldfish Mauthner(M-) cell. The M-cell receives pure'inhibitory projection from the contralateral VllIth nerve related through crossed second order vestibular interneurons. Their terminals are glycinergic and grouped on the soma. Tetanic stimulation of the posterior branch of the VIIIth nerve produces an LTP of the disynaptic inhibition which lasts more than 30min and is" specific to the tetanized pathway. Potentiation at the inhibitor), synapses on the M-cell is suggested by comparison between presynaptic volley potential and inhibitory postsynaptic conductance recorded simultaneously. To study more directly, we analyzed unitary inhibitor5' postsynaptic potentials(IPSPs) evoked by intracellular activation one inhibitor'), interneuron which included in the tetanized pathway. Depolarizing unitary IPSPs were recorded in the Cl-loaded M cell. The degree of Cl-loading was monitored with collateral IPSP. The time course of unitary IPSPs were equivalent to that of Vlllth newe-evoked IPSPs. The amplitude of unitary IPSPs were 3 ~ 1 0 % of Vlllth nerve-evoked IPSPs, and fluctuated in a quantal manner. After tetanie stimulation, the amplitude and underlying conductance of unitary IPSPs increased for more than 15min without any change in their time course. There was no significant change in spontaneous IPSPs and input resistance of the M-ceU. These results provide further evidence for the LTP of synaptic efficacy at the central inhibitor)' synapse.
2126
D I F F E R E N T T I I E R M A L D E P E N D E N C Y OF CUTANEOUS S Y M P A T H E T I C O U T F L O W T O T H E GLABROUS AND IIAIRY SKIN IN H U M A N S . SATOSHI IWASE, JUNICH! SUGENOYA*,
TADAAKi MANO, YOSHIKI SUGIYAMA, KIYOtHTO YAMAMOTO, TETSUYA OKAMOTO, Department of Autonomic and Behavioral Neurosciences, Division of ltigher Nervous Control, Research Institute of Environmental Medicine, Nagoya 464-01, and *Department of Physiology !!, Aichi Medical University,Nagakute, Aiehi 480-11, Japan This study investigates the effect of ambient temperature on the sudomotor and the vasoconstrictor components of skin sympathetic nerve activity (SSNA). The sympathetic traffic was measured by simultaneous microneurographie recording of SSNAs in the tibial and the peroneal nerves. When the ambient temperature was raised from 25°C to 34°C, both sudomotor and vasoconstrictor componentss of SSNA were enhanced in the peroneal nerve, but ~¢erc suppressed in the tibial nerve. The sudomotor and vasocontrictor sympathetic outflow was increased in both nerves when the temperature was lowered from 25°C to 18° C, but this increase was less prominent in the proneal nerve. Our results suggest that the sudomotor and the vasconstfictor components of SSNA are modulated by the ambient temperature. The differrence in sudomotor and vasoconstrictor components of SSNA in the tibia/and the peroneal nerves at different ambient temperature may be responsible for the regional difference in sweltting and vasoconstriction in the glabrous and the hairy skin.
2124
TRANSIENT CttANGES OF N E T W O R K ACTIVITY IN CULTURED CORTICAL NEURONS INDUCED BY Mg2+and APV EISAKII MAEDA 1, IIIIGtt P.C.ROBINSON ~, YOICItlRO KIIRODA 3 AND AI
21 25
L O N G - L A S T I N G P O T E N T I A T I O N A T T H E C E N T R A L I N H I B I T O R Y CONNECTIONS STUDIED BY UNITARY POSTSYNAPTIC POTENTIAL. CHIEKO SUMA, YUSUKE MURAYAMA and YOICHI ODA, Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Toyonaka, Osaka 560, Japan. Long-Term Potentiation(LTP) of inhibitor)' connection has been reported recently in the goldfish Mauthner(M-) cell. The M-cell receives pure'inhibitory projection from the contralateral VllIth nerve related through crossed second order vestibular interneurons. Their terminals are glycinergic and grouped on the soma. Tetanic stimulation of the posterior branch of the VIIIth nerve produces an LTP of the disynaptic inhibition which lasts more than 30min and is" specific to the tetanized pathway. Potentiation at the inhibitor), synapses on the M-cell is suggested by comparison between presynaptic volley potential and inhibitory postsynaptic conductance recorded simultaneously. To study more directly, we analyzed unitary inhibitor5' postsynaptic potentials(IPSPs) evoked by intracellular activation one inhibitor'), interneuron which included in the tetanized pathway. Depolarizing unitary IPSPs were recorded in the Cl-loaded M cell. The degree of Cl-loading was monitored with collateral IPSP. The time course of unitary IPSPs were equivalent to that of Vlllth newe-evoked IPSPs. The amplitude of unitary IPSPs were 3 ~ 1 0 % of Vlllth nerve-evoked IPSPs, and fluctuated in a quantal manner. After tetanie stimulation, the amplitude and underlying conductance of unitary IPSPs increased for more than 15min without any change in their time course. There was no significant change in spontaneous IPSPs and input resistance of the M-ceU. These results provide further evidence for the LTP of synaptic efficacy at the central inhibitor)' synapse.
2126
D I F F E R E N T T I I E R M A L D E P E N D E N C Y OF CUTANEOUS S Y M P A T H E T I C O U T F L O W T O T H E GLABROUS AND IIAIRY SKIN IN H U M A N S . SATOSHI IWASE, JUNICH! SUGENOYA*,
TADAAKi MANO, YOSHIKI SUGIYAMA, KIYOtHTO YAMAMOTO, TETSUYA OKAMOTO, Department of Autonomic and Behavioral Neurosciences, Division of ltigher Nervous Control, Research Institute of Environmental Medicine, Nagoya 464-01, and *Department of Physiology !!, Aichi Medical University,Nagakute, Aiehi 480-11, Japan This study investigates the effect of ambient temperature on the sudomotor and the vasoconstrictor components of skin sympathetic nerve activity (SSNA). The sympathetic traffic was measured by simultaneous microneurographie recording of SSNAs in the tibial and the peroneal nerves. When the ambient temperature was raised from 25°C to 34°C, both sudomotor and vasoconstrictor componentss of SSNA were enhanced in the peroneal nerve, but ~¢erc suppressed in the tibial nerve. The sudomotor and vasocontrictor sympathetic outflow was increased in both nerves when the temperature was lowered from 25°C to 18° C, but this increase was less prominent in the proneal nerve. Our results suggest that the sudomotor and the vasconstfictor components of SSNA are modulated by the ambient temperature. The differrence in sudomotor and vasoconstrictor components of SSNA in the tibia/and the peroneal nerves at different ambient temperature may be responsible for the regional difference in sweltting and vasoconstriction in the glabrous and the hairy skin.