Muscarinic and Nicotinic ACh Receptor Activation Differentially Mobilize Ca in Rat Intracardiac Ganglion Neurons
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Beker, Friederike, Martin Weber, Rainer H. A. Fink, and David J. Adams. Muscarinic and nicotinic ACh receptor activation differentially mobilize Ca in rat intracardiac ganglion neurons. J Neurophysiol 90: 1956–1964, 2003. First published May 21, 2003; 10.1152/jn.01079.2002. The origin of intracellular Ca concentration ([Ca ]i) transients stimulated by nicotinic (nAChR) and muscarinic (mAChR) receptor activation was investigated in fura-2-loaded neonatal rat intracardiac neurons. ACh evoked [Ca ]i increases that were reduced to 60% of control in the presence of either atropine (1 M) or mecamylamine (3 M) and to 20% in the presence of both antagonists. Removal of external Ca reduced ACh-induced responses to 58% of control, which was unchanged in the presence of mecamylamine but reduced to 5% of control by atropine. The nAChR-induced [Ca ]i response was reduced to 50% by 10 M ryanodine, whereas the mAChRinduced response was unaffected by ryanodine, suggesting that Ca release from ryanodine-sensitive Ca stores may only contribute to the nAChR-induced [Ca ]i responses. Perforated-patch whole cell recording at –60 mV shows that the rise in [Ca ]i is concomitant with slow outward currents on mAChR activation and with rapid inward currents after nAChR activation. In conclusion, different signaling pathways mediate the rise in [Ca ]i and membrane currents evoked by ACh binding to nicotinic and muscarinic receptors in rat intracardiac neurons.
منابع مشابه
Muscarinic and nicotinic ACh receptor activation differentially mobilize Ca in rat intracardiac neurons
The origin of intracellular Ca concentration ([Ca]i) transients stimulated by nicotinic (nAChR) and muscarinic (mAChR) receptor activation was investigated in fura-2 loaded neonatal rat intracardiac neurons. ACh evoked [Ca]i increases which were reduced to ~60% of control in the presence of either atropine (1 μM) or mecamylamine (3 μM) and to < 20% in the presence of both antagonists. Removal o...
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تاریخ انتشار 2003