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目的:研究钠尿肽对胃动力的作用及其可能的机制。方法:用四道记录仪记录胃窦环行肌条的自发性收缩活动;利用放射免疫技术测定cGMP的产生量;利用放射自显影技术分析钠尿肽受体在胃内的分布情况。结果:钠尿肽受体在大鼠胃的不同部位均有分布,但在胃窦部最多,ANP、BNP和CNP均能抑制胃窦环行肌条的自发性收缩,其中,CNP的作用尤为明显并呈剂量依赖关系,CNP的这种抑制性作用被鸟苷酸环化酶抑制剂LY83583所削弱,而用cGMP敏感的磷酸酯酶抑制剂zaparinist预处理时CNP的抑制作用明显增加,CNP明显提高胃窦环行肌cGMP的浓度,用非选择性钾通道阻断剂TEA预处理后发现CNP对胃窦环行肌自发性收缩活动的抑制作用明显减弱。结论:钠尿肽受体在大鼠的胃窦分布最多,CNP明显抑制大鼠胃窦环行肌的自发性收缩活动,CNP对大鼠胃窦环行肌自发性收缩活动的抑制效应是通过cGMP途径实现的,钾通道也参与CNP对大鼠胃窦平滑肌的舒张过程。
Objective: To study the effect of natriuretic peptide on gastric motility and its possible mechanism. Methods: The spontaneous contractile activity of circular muscle strips of gastric antrum was recorded with a four-channel recorder. The amount of cGMP produced was measured by radioimmunoassay. The distribution of natriuretic peptide receptors in the stomach was analyzed by autoradiography. Results: Natriuretic peptide receptors were distributed in different parts of the stomach of rats, but most of them were in the antrum. ANP, BNP and CNP all inhibited the spontaneous contractions of gastric antral myenteric strips, especially CNP And in a dose-dependent manner, this inhibitory effect of CNP was weakened by the guanylate cyclase inhibitor LY83583, whereas CNP inhibition was significantly increased and CNP significantly increased when pretreated with cGMP-sensitive phosphatase inhibitor zaparinist The concentration of cGMP in gastric antral circular muscle was significantly decreased after pretreatment with TEA, a nonselective potassium channel blocker, and found that CNP had an inhibitory effect on spontaneous contractile activity of gastric antral circular muscle. CONCLUSION: Natriuretic peptide receptors are the most abundant in the gastric antrum of rats, while CNP significantly inhibits the spontaneous contractile activity of the anterior circulation of gastric antrum in rats. The inhibitory effect of CNP on the spontaneous contractile activity of gastric antral circular muscle of rats is mediated through the cGMP pathway To achieve, potassium channels are also involved in CNP relaxation process of gastric smooth muscle in rats.