ObjectiveTo observe the effect of botulinum toxin type A (BTX-A) on the SP-induced smooth muscle contractility of gastric body and gastric fundus, so as to investigate the role of BTX-A in the binding between SP and NK1 receptor. MethodsMuscle strips were prepared from gastric body and gastric fundus and were randomly divided into control group, SP group, SP+APTL-SP (NK1 receptor antagonist) group, BTX-A group, BTX-A+SP group, and SP+BTX-A group. The contractility data were recorded by physiological experimental system of Biolap420E. ResultsSP significantly enhanced the tension and amplitude of gastric body contractility and the tension of gastric fundus contractility (P<0.01). APTL-SP signficantly inhibited SP-induced smooth muscle contractility tension in gastric body and gastric fundus (P<0.01). BTX-A significantly inhibited the smooth muscle contractility amplitude in gastric body and gastric fundus (P<0.01). BTX-A significantly inhibited SP-induced smooth muscle contractility, including the tension (P<0.05, 0.01) and amplitude (P<0.01) in the gastric body and gastric fundus. After BTX-A treatment, SP did not enhance the smooth muscle contractility of the gastic body and gastric fundus in vitro. ConclusionSP can enhance the spontaneous contractility of smooth muscle in the gastric body and gastric fundus; BTX-A can inhibit SP-induced smooth muscle contractility of both gastric body and gastric fundus.