Inhibitory effect of botulinum toxin type A on acetylcholine induced contractile response in rat pyloric smooth muscle in vitro

Abstract

Abstract: AIM: To investigate the effect of botulinum toxin type A (BTX-A) on endogenous and exogenous acetylcholine (ACh) induced contractile response in rat pyloric smooth muscle in vitro.METHODS: The effects of BTX-A and atropine on pyloric contractility-induced respectively by electrical field stimulation (EFS), which is used to promote endogenous ACh release, and by ACh addition were comparatively evaluated.RESULTS: BTX-A inhibited the pyloric smooth muscle contractility-induced by EFS (P<0.001). Both of atropine and BTX-A significantly abolished pyloric contractility-induced by ACh (P<0.001), but BTX-A incompletely did it.CONCLUSION: The evidence of the inhibitory effect of BTX-A on pyloric contractility-induced by EFS suggests that BTX-A inhibits endogenous ACh release through cleaving SNAP-25 protein within presynaptic membrane. The result of the inhibition of BTX-A on ACh induced pyloric contractile response is similar to atropine, suggests that BTX-A probably acts on postsynaptic receptor or pyloric muscle directly.

Key words: Botulinum toxin type A, Acetylcholine, in vitro, Pyloric smooth muscle

CLC Number:

R994.1

XU Gui-zhong, LIU Xiang-wen, HOU Yi-ping. Inhibitory effect of botulinum toxin type A on acetylcholine induced contractile response in rat pyloric smooth muscle in vitro[J]. Chinese Journal of Clinical Pharmacology and Therapeutics, 2010, 15(12): 1383-1387.

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