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S2-5 Intracellular modulation of nociceptive signals in the rat dorsal commissural neurons by noradrenaline and serotonin
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S2-3 BRADYKININ 82 RECEPTOR-ACTIVATED Ca INFLUX; INTERACTION OF IP4. fZfS-GAP IP4-BINDING PROTEIN, AND PROTEIN TYROSINE PHOSPHORYlATlON.HARUHIRO HIGASHIDA , MINAKO HASHII, MEGUMI TAKETO, AND SHIGERU YOKOYAMA Department of Biophysics, Kanazawa University School of Medicine, Kanazawa 920, Japan We have reported that application of bradykinin (BK), a neuropeptide, increases in [Ca2”)‘, which is extracellular Ca2’-dependent in Ki-ras-transformed NIH/3T3 (DT) fibroblasts. Activation of BK 82 receptors resulted in a decrease of cellular fluorescence at the excitation wavelength of 360 nm after MnC2 application in DT cells. This Mn2+ entry increased with membrane hyperpolarization. Internal application of Ins(l,3,4,5)P4 mimicked the membrane potential-dependent Mn2’ entry. BK- and InsP4-induced Ca2’ influx was blocked by a tyrosine kinase inhibitor, genistein. Bradykinin receptor activation induced tyrosine phosphorylation of MAP kinase, which was inhibited by genistein. These results suggest that two 82 receptor-activated signal pathways, protein tyrosine phosphorylation and InsP4, merge at the hyperpolarization-activated Ca2’ influx process in ras-transformed NIH/3T3 fibroblasts.
S2-4 INTRACELLULAR Ca2’ SIGNALLING AND INOSITOL TRISPHOSPHATE RECEPTOR. KATSUHIKO MIKOSHIBA, TEIICHI FURUICHI, ATSUHI MIYAWAKI, SHOEN KUME, AKIRA MUTO, TAKAFUMI INOUE, TAKAYUKI MICHIKAWA, JUNJI HIROTA,DAISUKE YASUTOMI, HIROYUKI YONESHIMA AND FUMIO YOSHIKAWA Department of Molecular Neurobiology, The Institute of Medical Science,The University of Tokyo, Tokyo, Japan. InsP%induced calcium release (IICR) is mediated by an intracellular calcium release channel InsP3 receptor (InsP3R). The basic structure of all InsP3R types is composed of three functional domains; the ligand-binding domain (N-terminal portion); the modulatory domain (middle portion) which contains various sites for modulator-binding (ATP, calmodulin, Ca2’, etc.) and phosphoryiation (PKA, PKC, CaMKII); the channel domain (C-terminal portion) which contains six membrane-spanning segments and one putative “pore”-forming segment as the ion channel superfamily. InsP3R forms a tetramer complex, IP3-induced Ca2’ release of the purified Calcium waves and oscillations in hamster eggs were InsP3R exhibited positive cooperativity. clearly blocked by InsP3R antibody. Introduction of the antisense nucleotide of the cDNA of Xenopus InsP3R, suppressed the egg activation lnsP3 deficient mice show epileptic seizure and ataxic gait. These results suggest that intracellular calcium release plays important roles in neural signal processing as well as the essential functions in other systems. s2-5 INTRACELLULAR MODULATION OF NOCICEPTIVE SIGNALS IN THE RAT DORSAL COMMISSURAL NEURONS BY NORADRENALINE AND SEROTONIN. NORIO AKAIKE AND TIAN-LE XU Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka 812-82, Japan The intracellular modulatory effects of noradrenaline (NA) and serotonin (5-HT) on glycine (Gly) response were investigated in neurons acutely dissociated from the rat sacral dorsal commissural nucleus (SDCN) using nystatin perforated patch recording mode. The activation of a2-adrenoceptor coupled to IAP-sensitive Gi protein decreased cAMP formation, resulting in the decrease of PKA activity which potentiates the Gly response. The activation of 5HT2 receptor coupled to IAP-insensitive G-protein increased diacylglycerol (DAG) formation. The accumulation of DAG increased Ca2’-independent PKC activity, resulting in the potentiation of the Gly response in SDCN neurons. These data clearly indicate the existence of functional cross-talk between the two agonist-operated intracelluler mechanisms in the potentiation of Gly response. Consequently, it is feasible that NA and 5HT inputs to SDCN modulate the nociceptive signals as pain by enhancing the Gly response.
S2-3 BRADYKININ 82 RECEPTOR-ACTIVATED Ca INFLUX; INTERACTION OF IP4. fZfS-GAP IP4-BINDING PROTEIN, AND PROTEIN TYROSINE PHOSPHORYlATlON.HARUHIRO HIGASHIDA , MINAKO HASHII, MEGUMI TAKETO, AND SHIGERU YOKOYAMA Department of Biophysics, Kanazawa University School of Medicine, Kanazawa 920, Japan We have reported that application of bradykinin (BK), a neuropeptide, increases in [Ca2”)‘, which is extracellular Ca2’-dependent in Ki-ras-transformed NIH/3T3 (DT) fibroblasts. Activation of BK 82 receptors resulted in a decrease of cellular fluorescence at the excitation wavelength of 360 nm after MnC2 application in DT cells. This Mn2+ entry increased with membrane hyperpolarization. Internal application of Ins(l,3,4,5)P4 mimicked the membrane potential-dependent Mn2’ entry. BK- and InsP4-induced Ca2’ influx was blocked by a tyrosine kinase inhibitor, genistein. Bradykinin receptor activation induced tyrosine phosphorylation of MAP kinase, which was inhibited by genistein. These results suggest that two 82 receptor-activated signal pathways, protein tyrosine phosphorylation and InsP4, merge at the hyperpolarization-activated Ca2’ influx process in ras-transformed NIH/3T3 fibroblasts.
S2-4 INTRACELLULAR Ca2’ SIGNALLING AND INOSITOL TRISPHOSPHATE RECEPTOR. KATSUHIKO MIKOSHIBA, TEIICHI FURUICHI, ATSUHI MIYAWAKI, SHOEN KUME, AKIRA MUTO, TAKAFUMI INOUE, TAKAYUKI MICHIKAWA, JUNJI HIROTA,DAISUKE YASUTOMI, HIROYUKI YONESHIMA AND FUMIO YOSHIKAWA Department of Molecular Neurobiology, The Institute of Medical Science,The University of Tokyo, Tokyo, Japan. InsP%induced calcium release (IICR) is mediated by an intracellular calcium release channel InsP3 receptor (InsP3R). The basic structure of all InsP3R types is composed of three functional domains; the ligand-binding domain (N-terminal portion); the modulatory domain (middle portion) which contains various sites for modulator-binding (ATP, calmodulin, Ca2’, etc.) and phosphoryiation (PKA, PKC, CaMKII); the channel domain (C-terminal portion) which contains six membrane-spanning segments and one putative “pore”-forming segment as the ion channel superfamily. InsP3R forms a tetramer complex, IP3-induced Ca2’ release of the purified Calcium waves and oscillations in hamster eggs were InsP3R exhibited positive cooperativity. clearly blocked by InsP3R antibody. Introduction of the antisense nucleotide of the cDNA of Xenopus InsP3R, suppressed the egg activation lnsP3 deficient mice show epileptic seizure and ataxic gait. These results suggest that intracellular calcium release plays important roles in neural signal processing as well as the essential functions in other systems. s2-5 INTRACELLULAR MODULATION OF NOCICEPTIVE SIGNALS IN THE RAT DORSAL COMMISSURAL NEURONS BY NORADRENALINE AND SEROTONIN. NORIO AKAIKE AND TIAN-LE XU Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka 812-82, Japan The intracellular modulatory effects of noradrenaline (NA) and serotonin (5-HT) on glycine (Gly) response were investigated in neurons acutely dissociated from the rat sacral dorsal commissural nucleus (SDCN) using nystatin perforated patch recording mode. The activation of a2-adrenoceptor coupled to IAP-sensitive Gi protein decreased cAMP formation, resulting in the decrease of PKA activity which potentiates the Gly response. The activation of 5HT2 receptor coupled to IAP-insensitive G-protein increased diacylglycerol (DAG) formation. The accumulation of DAG increased Ca2’-independent PKC activity, resulting in the potentiation of the Gly response in SDCN neurons. These data clearly indicate the existence of functional cross-talk between the two agonist-operated intracelluler mechanisms in the potentiation of Gly response. Consequently, it is feasible that NA and 5HT inputs to SDCN modulate the nociceptive signals as pain by enhancing the Gly response.