Substance P and acetylcholine both suppress the same K+ current in dissociated smooth muscle cells.
Substance P and acetylcholine both suppress the same K+ current in dissociated smooth muscle cells.
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P 物质和乙酰胆碱都抑制游离平滑肌细胞中相同的 K 电流。
DOI：
10.1152/ajpcell.1986.251.4.c580
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Singer,JJ
中科院分区：
文献类型：
--
作者：
Sims,SM;WalshJr,JV;Singer,JJ
通过电生理学检查 P 物质对新鲜分离的胃平滑肌细胞的影响。 Substance P caused depolarization, associated with a membrane conductance decrease, which led to the generation of action potentials and contraction. When the membrane potential was held constant under voltage clamp, substance P induced a net inward current, also associated with a conductance decrease. The net inward current resulted from suppression of an outward K+ current, one which resembled the acetylcholine-sensitive M-current in these cells.当 P 物质最大限度地抑制这种向外的 K+ 电流时，乙酰胆碱 (ACh) 没有额外的作用。相反，当ACh完全抑制M电流时，P物质没有额外的作用。这些结果表明 P 物质抑制受 ACh 影响的相同外向 K+ 电流。在这些实验中研究的大约一半（85 个细胞中的 44 个）细胞中观察到 P 物质对 M 电流的抑制。在那些对 P 物质没有反应的细胞中，ACh 仍然能够抑制 M 电流。 Thus both substance P and cholinergic agonists appear to exert their excitatory effects on smooth muscle cells by inhibiting a common K+ current.
The effect of substance P on freshly dissociated gastric smooth muscle cells was examined electrophysiologically. Substance P caused depolarization, associated with a membrane conductance decrease, which led to the generation of action potentials and contraction. When the membrane potential was held constant under voltage clamp, substance P induced a net inward current, also associated with a conductance decrease. The net inward current resulted from suppression of an outward K+ current, one which resembled the acetylcholine-sensitive M-current in these cells. When substance P maximally suppressed this outward K+ current, acetylcholine (ACh) had no additional effect. Conversely, when ACh fully suppressed the M-current, substance P was without additional effect. These results indicate that substance P suppresses the same outward K+ current affected by ACh. Suppression of M-current by substance P was observed in approximately half (44 of 85) of the cells studied in these experiments. In those cells that did not respond to substance P, ACh was nevertheless capable of suppressing the M-current. Thus both substance P and cholinergic agonists appear to exert their excitatory effects on smooth muscle cells by inhibiting a common K+ current.