Comparative study in the effect of C-type natriuretic peptide on gastric motility in various animals
Comparative study in the effect of C-type natriuretic peptide on gastric motility in various animals
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C型利钠肽对不同动物胃动力影响的比较研究。
DOI：
10.3748/wjg.v9.i3.547
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发表时间：
2003-03-01
影响因子：
4.3
通讯作者：
Xu, WX
中科院分区：
文献类型：
--
作者：
Guo, HS;Jin, Z;Xu, WX
目的：为探讨利钠肽对不同动物胃运动的影响，比较了C型利钠肽（CNP）对离体大鼠、豚鼠和人胃平滑肌自发性收缩的影响。CNP使豚鼠和大鼠胃窦环行肌的自发收缩幅度明显降低，但对收缩频率无影响。CNP可完全抑制胃窦纵行平滑肌的收缩活动。CNP完全抑制人胃窦环行和纵行平滑肌的自发收缩。在豚鼠和大鼠胃底环形平滑肌，CNP可明显降低其自发收缩的幅度，但不影响其频率;而在胃底纵行平滑肌，CNP可完全抑制其收缩活动。在豚鼠胃体的环形和纵向平滑肌中，CNP首先引起松弛，然后引起自发收缩（反弹收缩）的幅度增加，但频率没有改变。用M受体阻断剂阿托品预处理胃体环平滑肌后，胃体环平滑肌的反跳收缩被取消，CNP使胃体环平滑肌和胃体纵肌的自发收缩出现短暂的轻度舒张，随后幅度恢复，但对收缩频率无影响。用阿托品预处理后，平滑肌由短暂的轻度松弛变为长时程的完全抑制; CNP诱导的抑制百分比在胃环行肌中为76.77 +/-6.21%（胃底）、67.21 +/-5.32%（体）和58.23 +/-6.21%（胃窦），然而，对豚鼠胃纵行平滑肌的抑制率分别为100 ± 0.00%（胃底）、68.66 ± 3.55%（体）和100 ± 0.00%（胃窦）;在大鼠中，CNP诱导的胃环形平滑肌抑制百分比为95.87 +/-4.12%（胃底）、94.91 +/-5.08%（体）和66.32 +/-7.32%（胃窦），而在纵行平滑肌，CNP完全抑制自发收缩。用鸟苷酸环化酶抑制剂LY 83583和磷酸酯酶抑制剂扎肝素司特抑制cGMP的生成，LY 83583可明显减弱CNP对自发收缩的抑制作用，而扎肝素司特则增强CNP的抑制作用。（1）CNP对大鼠、豚鼠和人胃窦环行和纵行平滑肌的自发性收缩均有明显的抑制作用。抑制效力的顺序为人>大鼠>豚鼠。(2)在同一动物中，CNP对胃底平滑肌自发收缩的抑制作用最强，对胃窦平滑肌的抑制作用最弱;在同一部位，CNP对环平滑肌的抑制作用强于纵肌。(3)CNP对胃平滑肌自发收缩的抑制作用由cGMP依赖性途径介导。
AIM: To investigate the effect of natriuretic peptides on gastric motility in various animals, and the effect of C-type natriuretic peptide (CNP) on spontaneous contraction of gastric smooth muscle in rat, guinea-pig and human in vitro was compared.METHODS: Spontaneous contraction of gastric smooth muscle was recorded by four channel physiograph.RESULTS: In the guinea-pig and rat gastric antral circular smooth muscle, CNP markedly decreased the amplitude of spontaneous contraction but it didn't affect the frequency, however, the contractile activity was completely inhibited by CNP in gastric antral longitudinal smooth muscle. In the human gastric antral circular and longitudinal smooth musle, CNP completely inhibited spontaneous contraction. In the circular smooth muscle of guinea-pig and rat gastric fundus, CNP obviously decreased the amplitude of spontaneous contraction but it didn't affect the frequency, however, the contractile activity was completely inhibited by CNP in smooth muscle of fundus longitudinal. In the circular and longitudinal smooth muscle of guinea-pig gastric body, CNP at first induced a relaxation and then an increase in amplitude of spontaneous contraction (rebound contraction), but the frequency was not changed. After the circular smooth muscle of gastric body was pretreated with atropine, an M receptor blocker, the rebound contraction was abolished; In circular and longitudinal smooth muscle of rat gastric body, CNP induced a transient and slight relaxation and successively followed by the recovery in amplitude of spontaneous contraction but it also didn't affect the frequency. After the smooth muscle was pretreated with atropine, the transient and slight relaxation was replaced by long term and complete inhibition; The percentage of CNP-induced inhibition was 76.77 +/- 6.21 % (fundus), 67.21 +/- 5.32 % (body) and 58.23 +/- 6.21 % (antral) in the gastric circular muscle, however, the inhibitory percentage was 100 +/- 0.00 % (fundus), 68.66 3.55 % (body) and 100 +/- 0.00 % (antrum) in the gastric longitudinal smooth muscle of guinea-pigs; In the rat, the percentage of CNP-induced inhibition was 95.87 +/- 4.12 (fundus), 94.91 +/- 5.08 % (body) and 66.32 +/- 7.32 % (antrum) in the gastric circular smooth muscle, but in the longitudinal smooth muscle, CNP completely inhibited the spontaneous contraction. Using LY83583, a guanylate cyclase inhibitor, and zaparinast as a phosphoesterase inhibitor to inhibit the generation of cGMP, the effect of CNP on the spontaneous contraction was markedly weakened by LY83583, however, the inhibitory effect was enhanced by zaparinast.CONCLUSION: (1) CNP can obviously inhibit the spontaneous contraction of gastric antral circular and longitudinal smooth muscle in the rat, guinea-pig and human. The order of inhibitory potency is human >rat> guinea-pig. (2) In the same animals, the inhibitory effect of CNP on spontaneous contraction is the most powerful in fundus and the weakest in antrum, in the same position, the inhibitory effect on the circular smooth muscle is more powerful than that on longitudinal smooth muscle. (3) The inhibitory effect of CNP on spontaneous contraction in the gastric smooth muscle is mediated by a cGMP dependent pathway.