嘌呤拟似物对豚鼠胃窦环行肌自发性收缩及电活动的影响  

Effects of purinergic analogues on spontaneous contraction and electrical activities of gastric antral circular muscle in guinea-pig

作　　者：金政[1] 郭慧淑[2] 许东元[2] 洪明玉[2] 李香兰[2] 许文燮[1] 

机构地区：[1]上海交通大学医学院生理学教研室,上海200030 [2]延边大学医学院生理学教研室,延吉133000

出　　处：《生理学报》2004年第6期678-684,共7页Acta Physiologica Sinica

基　　金：This work was supported by the National Nature Science Foundation of China (NO. 30160028).

摘　　要：为探讨非肾上腺素能非胆碱能神经递质对胃窦环行肌功能的调节作用,在离体胃平滑肌上观察了嘌呤拟似物对胃窦环行肌自发性收缩活动和电活动的影响。电活动用传统的细胞内微电极记录,并和收缩活动同步描记于多道生理记录仪。结果表明,嘌呤能P2Y 受体激动剂, 三磷酸腺苷(ATP)和2-methylthio ATP (2-MeSATP) 均增强胃窦平滑肌的收缩活动, 但不影响电活动, 而且ATP 和2-MeSATP 对胃平滑肌收缩活动的增强作用可被嘌呤能 P2Y 受体阻断剂, reactive blue-2 和苏拉明(suramin)所阻断。用 100 μmol/L α,β-MeATP 引起的脱敏感使 P2X 受体被阻断, ATP 增强胃窦平滑肌收缩活动的效应不受影响。嘌呤能 P2X 受体激动剂,α,β-MeATP 明显抑制胃窦环行肌自发性收缩活动,同时使膜电位明显超极化。ATP 对胃窦平滑肌的收缩作用不被L 型钙通道阻断剂尼卡地平(nicardipine)阻断,但细胞外用无钙液灌流时这种效应则完全被阻断。用前列腺素合成抑制剂消炎痛预先处理20 min 后, ATP 和2-MeSATP 仍能增强胃窦平滑肌的自发性收缩活动。以上结果提示:(1)ATP 和 2-MeSATP 通过嘌呤能 P2Y 受体增强胃窦平滑肌的自发性收缩活动,而 α,β-MeATP 或 β,γ-MeATP 通过嘌呤能 P2X受体使膜电位超极化, 引起胃窦平滑肌的舒张;(2) ATPIn order to investigate the role of non-adrenergic non-cholinergic nerves in regulating mechanical and electrical activity of gastric circular smooth muscle, the effects of ATP and its analogues on gastric motility and electrical activities were observed in guinea-pig. In organ bath system, isometric force of the circular smooth muscle of guinea-pig gastric antrum was measured. Electrical activity of the muscle was recorded by using intracellular microelectrode. Electrical and mechanical activities were recorded by chart recorder. ATP and 2-MeSATP potentiated the mechanical activity but didn’t affect electrical activity in gastric circular smooth muscle. ATP and 2- MeSATP-induced contraction was effectively blocked by nonselective P2y-purinoceptor antagonist, reactive-blue-2 and suramin, but ATP-induced contraction was not blocked by α,β-MeATP-induced desensitization of P2x-purinoceptors. However, α,β-MeATP, P2x- purinoceptor agonist, attenuated slow waves with membrane hyperpolarization and inhibited contraction. The relaxation by β,γ- MeATP was blocked by α,β-MeATP-induced desensitization of P2x-purinoceptors. ATP-induced contraction was blocked by external calcium-free, but not by nicardipine, a L-type calcium channel blocker. Indomethacin, a nonselective cyclooxygenase inhibitor, did not block ATP-induced contraction. The results suggest that: (1) ATP- and analogues-induced contraction is mediated by P2y-purinoceptor, whereas α,β-MeATP-induced relaxation by P2x-purinoceptor in guinea-pig gastric antral circular smooth muscle. (2) ATP-induced contraction is dependent on extracellular calcium, but Ca2+ entry is not mediated by L-type calcium channel. (3) Prostaglandins are not involved in ATP- and analogue-induced contraction of gastric circular smooth muscle in guinea-pigs, and α,β-MeATP-induced relaxation is related to membrane hyperpolarization.

关 键 词：ATP 嘌呤P2Y受体 嘌呤P2X受体 胃窦环行肌 

分 类 号：Q421[生物学—神经生物学]