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NPY Y2-receptor mediated calcium influx in neuroblastoma cells
NEUROPEPTIDES:
APRIL
15
SUPPLEMENT
C4/6 Neuropeptide Y Inhibits Catecholamine Secretion from Single Bovine Chromaffin Cells by a Decrease in Intracellular CAMP N. Limberger*, W. Niirenberg*, K. Takedat and P. Illes* *Pharmakologisches Institut, Hermann-Herder-Strasse 5, D-79 104 Freiburg, Germany and tUniversit6 Louis Pasteur de Strasbourg, Laboratoire de Pharmacologic, CNRS URA600, F-67401 Illkirch, France In cultured bovine chromaffin cells, activation ofnicotinic acetylcholine receptors initiates a cationic inward current and a subsequent secretion of catecholamines. It has been shown that neuropeptide Y (NPY) and its C-terminal fiagment inhibit the nicotine-induced current.’ In the present study, fast cyclic voltammetry was used to determine nicotine-induced release of endogenous catecholamines from single chromaffin cells. A small carbon fibre electrode was placed about 5 pm apart from a cell, and the current resulting from the catecholamine oxidation was measured. Pressure application of nicotine (10 pM) for 10 s evoked a catecholamine secretion corresponding to 1.2 f 0.1 pM noradrenaline (n = 78). Repeated nicotine-applications at 3 min intervals produced stable secretion-responses. The secretion was abolished in the absence of Ca” andreduced by about 90% in the presence of hexamethonium (100 pM). NPY(18-36) (0.2-20 PM), when applied for 30 s, caused a marked oxidation signal by itself which disappeared within a 10 min washout period. However, the nicotine-induced secretion was decreased for a fUrther 15 min. 8-Bromo-CAMP (100 pM) increased the catecholamine secretion by about 80%. 8-Bromo-CAMP also abolished the effect of NPY( 18-36) (2 PM). Pressure application of K+ (50 mM; 10 s) induced a catecholamine secretion corresponding to 1.6 f 0.3 pM noradrenaline (n = 16). The K+-induced secretion was not affected by NPY( 18-36) (20 pM). In conclusion, NPY reduces nicotine induced catecholamine secretion in bovine chromaffin cells by decreasing the intracellular CAMP concentration. 1. Niirenberg, W., Illes, P. and Takeda, K. Neuropeptide Y inhibits nicotinic cholinergic currents but not voltage-dependent calcium currents in bovine chromaffin cells. Pfliigers Arch. 1991; 418: 34C352.
P4/1 Neuropeptide Y Inhibits Glutamate Release From Rat Hippocampal Slices Through The Y, Receptor C. Schwarzer, S. Greber and G. Sperk
potassium stimulated, calcium dependent release of glutamate in superfused slices from the rat hippocampus. NPY and the Y, receptor agonist NPY,,_,, inhibited glutamate release by up to 60% in a dose-dependent manner (3-100 nM). Higher concentrations ofNPY,,,, showed a partial reversal of the dose response curve and resulted in about 30% inhibition ofglutamate release. In contrary, the Y, receptor agonist [Leu)‘] [Pro34]NPY at 100 nM resulted in an enhancement of glutamate release by about 15%. PYY was equally potent in inhibiting release as NPY. Pancreatic polypeptide Y (PPY) was inactive. Our data suggest a differential regulation of glutamate release from hippocampal slices through Y, and Y, receptors.
P4/2 NPY Y,-Receptor Mediated Calcium Influx in Neuroblastoma Cells V. Soares Lemos, J. W. Lynch, B. Bucher, J. C. Stoclet and K. Takeda Universitb Louis Pasteur, Pharmacologic-CNRS URABOO, Strasbourg 6740 1, France Activation ofneuropeptide Y,-type receptors produce several different cellular responses and the associated transduction mechanisms are poorly characterized. In CHP-234 human neuroblastoma cells, Y, receptor stimulation caused increases in [Ca”], which were absolutely dependent on the presence of Ca2+in the bathing solution. Depolarization with KC1 was without effect, suggesting that NPY responses did not involve voltage-dependent Ca?’ channels. The NPY-induced [Ca2+],increase was not due to capacitative Ca2+ entry sensitive to internal CaZ+ store levels. The [Ca*+],elevation was blocked by Ni2+and Fura- fluorescence was quenched by MnZ+ only in the presence of NPY, indicating that Ca2+ entry was linked tightly to receptor activation. Although thapsigargin- and ryanodine-sensitive Ca2+ stores were present, NPY responses were unchanged by pretreatment with either drug. Pertnssis toxin did not affect the NPY-stimulated [Ca2+], increase, but did abolish NPY-dependent inhibition of CAMP production. It is concluded that NPY YZtype receptors couple directly to receptor-operated Ca”+ channels without involvement of intracellular Ca2+stores and that NPY Y,-type receptors can activate both pertussis toxin-sensitive and -insensitive mechanisms in the same cell.
Department of Pharmacology, University of Innsbruck, 6020 Austria
P413 Opposite Pre- and Postsynaptic Effects of Neuropeptide Y on Rat Locus Coeruleus Neurones K. Nieber, E. P. Finta and P. Illes
Effects of Neuropeptide Y (NPY), peptide YY (PYY), [Leu3’] [Pro34]NPY and NPY,,_,, were investigated upon
Pharmakologisches Institut der Universitit, HermannHerder-Strasse 5, D-79 104 Freiburg, Germany
APRIL
15
SUPPLEMENT
C4/6 Neuropeptide Y Inhibits Catecholamine Secretion from Single Bovine Chromaffin Cells by a Decrease in Intracellular CAMP N. Limberger*, W. Niirenberg*, K. Takedat and P. Illes* *Pharmakologisches Institut, Hermann-Herder-Strasse 5, D-79 104 Freiburg, Germany and tUniversit6 Louis Pasteur de Strasbourg, Laboratoire de Pharmacologic, CNRS URA600, F-67401 Illkirch, France In cultured bovine chromaffin cells, activation ofnicotinic acetylcholine receptors initiates a cationic inward current and a subsequent secretion of catecholamines. It has been shown that neuropeptide Y (NPY) and its C-terminal fiagment inhibit the nicotine-induced current.’ In the present study, fast cyclic voltammetry was used to determine nicotine-induced release of endogenous catecholamines from single chromaffin cells. A small carbon fibre electrode was placed about 5 pm apart from a cell, and the current resulting from the catecholamine oxidation was measured. Pressure application of nicotine (10 pM) for 10 s evoked a catecholamine secretion corresponding to 1.2 f 0.1 pM noradrenaline (n = 78). Repeated nicotine-applications at 3 min intervals produced stable secretion-responses. The secretion was abolished in the absence of Ca” andreduced by about 90% in the presence of hexamethonium (100 pM). NPY(18-36) (0.2-20 PM), when applied for 30 s, caused a marked oxidation signal by itself which disappeared within a 10 min washout period. However, the nicotine-induced secretion was decreased for a fUrther 15 min. 8-Bromo-CAMP (100 pM) increased the catecholamine secretion by about 80%. 8-Bromo-CAMP also abolished the effect of NPY( 18-36) (2 PM). Pressure application of K+ (50 mM; 10 s) induced a catecholamine secretion corresponding to 1.6 f 0.3 pM noradrenaline (n = 16). The K+-induced secretion was not affected by NPY( 18-36) (20 pM). In conclusion, NPY reduces nicotine induced catecholamine secretion in bovine chromaffin cells by decreasing the intracellular CAMP concentration. 1. Niirenberg, W., Illes, P. and Takeda, K. Neuropeptide Y inhibits nicotinic cholinergic currents but not voltage-dependent calcium currents in bovine chromaffin cells. Pfliigers Arch. 1991; 418: 34C352.
P4/1 Neuropeptide Y Inhibits Glutamate Release From Rat Hippocampal Slices Through The Y, Receptor C. Schwarzer, S. Greber and G. Sperk
potassium stimulated, calcium dependent release of glutamate in superfused slices from the rat hippocampus. NPY and the Y, receptor agonist NPY,,_,, inhibited glutamate release by up to 60% in a dose-dependent manner (3-100 nM). Higher concentrations ofNPY,,,, showed a partial reversal of the dose response curve and resulted in about 30% inhibition ofglutamate release. In contrary, the Y, receptor agonist [Leu)‘] [Pro34]NPY at 100 nM resulted in an enhancement of glutamate release by about 15%. PYY was equally potent in inhibiting release as NPY. Pancreatic polypeptide Y (PPY) was inactive. Our data suggest a differential regulation of glutamate release from hippocampal slices through Y, and Y, receptors.
P4/2 NPY Y,-Receptor Mediated Calcium Influx in Neuroblastoma Cells V. Soares Lemos, J. W. Lynch, B. Bucher, J. C. Stoclet and K. Takeda Universitb Louis Pasteur, Pharmacologic-CNRS URABOO, Strasbourg 6740 1, France Activation ofneuropeptide Y,-type receptors produce several different cellular responses and the associated transduction mechanisms are poorly characterized. In CHP-234 human neuroblastoma cells, Y, receptor stimulation caused increases in [Ca”], which were absolutely dependent on the presence of Ca2+in the bathing solution. Depolarization with KC1 was without effect, suggesting that NPY responses did not involve voltage-dependent Ca?’ channels. The NPY-induced [Ca2+],increase was not due to capacitative Ca2+ entry sensitive to internal CaZ+ store levels. The [Ca*+],elevation was blocked by Ni2+and Fura- fluorescence was quenched by MnZ+ only in the presence of NPY, indicating that Ca2+ entry was linked tightly to receptor activation. Although thapsigargin- and ryanodine-sensitive Ca2+ stores were present, NPY responses were unchanged by pretreatment with either drug. Pertnssis toxin did not affect the NPY-stimulated [Ca2+], increase, but did abolish NPY-dependent inhibition of CAMP production. It is concluded that NPY YZtype receptors couple directly to receptor-operated Ca”+ channels without involvement of intracellular Ca2+stores and that NPY Y,-type receptors can activate both pertussis toxin-sensitive and -insensitive mechanisms in the same cell.
Department of Pharmacology, University of Innsbruck, 6020 Austria
P413 Opposite Pre- and Postsynaptic Effects of Neuropeptide Y on Rat Locus Coeruleus Neurones K. Nieber, E. P. Finta and P. Illes
Effects of Neuropeptide Y (NPY), peptide YY (PYY), [Leu3’] [Pro34]NPY and NPY,,_,, were investigated upon
Pharmakologisches Institut der Universitit, HermannHerder-Strasse 5, D-79 104 Freiburg, Germany