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KMID : 0358619940280010051
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Korean Journal of Physiology
1994 Volume.28 No. 1 p.51 ~ p.59
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The Excitatory Mechanism of Substance P in the Antral Circular Muscle of Guinea Pig Stomach
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Jun Jae-Yeoul
Kim Sung-Joon
Choi Youn-Baik
Kim Ki-Whan
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Abstract
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This study was carried out to elucidate the excitatory mechanisms of Substance P in the antral circular muscle, using isometric contraction recording, conventional microelectrode method and whole-cell patch clamp technique. Substance P produced tonic and phasic contractions in a dose-dependent manner and depolarized membrane potential with increased amplitude of slow waves in muscle strips. Voltage-dependent currents were increased by the application of Substance P from a holding potential of -60mV to 50mV in 10mV steps and this effect was blocked by the addition of an antagonist. Also Substance P increased transient and spontaneous oscillatory outward currents. The enhanced outward currents were abolished by apamin in dispersed single cells. These results suggest that the depolarization of membrane potential by Substance P activates voltage-dependent channels, which represents an excitatory response in the antral circular muscle and led to an increase in .
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KEYWORD
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Slow wave, Antral myocytes, Substance P, Voltage-dependent currents, activated currents
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