Sakamoto Y
Department of Physiology, School of Medicine, Fukuoka University, Japan.
J Smooth Muscle Res. 1999 Apr;35(2):23-31. doi: 10.1540/jsmr.35.23.
Carbachol (CCh, 10(-6) M) induced biphasic contraction of longitudinal muscle of the guinea pig stomach, consisting of rapid phasic contraction and contracture. The contracture was almost completely inhibited by sodium nitroprusside (SNP, 10(-6) M) and S-nitroso-N-acetyl penicillamine (SNAP, 10(-6) M). A membrane permeable analogue of cyclic GMP, 8Br-cGMP (10(-4) M), also inhibited the CCh induced contracture. Although a heme site inhibitor of nitric oxide-sensitive guanylyl cyclase, 1-H-[1, 2, 4] oxadiazolo-[4, 3 a]quinoxalin-1-one (ODQ; 10(-6) M), reduced the inhibitory action of SNP, it did not affect the inhibitory action of 8Br-cGMP, indicating that the effect of SNP was developed via cyclic GMP production in the presence of D600. Charybdotoxin (10(-7) M), an inhibitor of Ca2+ activated K+ channel, did not influence on the CCh induced contracture. On the other hand, CCh induced a depolarization of the longitudinal muscle cell membrane (from -60 mV to -45 mV) in the presence of 10(-6) M D600, but SNP did not affect the depolarization. These results suggest that in the presence of D600 SNP induces relaxation of CCh induced contracture of the longitudinal muscle of the guinea pig stomach via cyclic GMP but not membrane potential dependent mechanism.
卡巴胆碱（CCh，10⁻⁶ M）可诱导豚鼠胃纵行肌出现双相收缩，包括快速的相位性收缩和挛缩。硝普钠（SNP，10⁻⁶ M）和S-亚硝基-N-乙酰青霉胺（SNAP，10⁻⁶ M）几乎完全抑制了这种挛缩。环鸟苷酸（cGMP）的膜通透性类似物8-溴-cGMP（10⁻⁴ M）也抑制了CCh诱导的挛缩。尽管一氧化氮敏感性鸟苷酸环化酶的血红素位点抑制剂1-H-[1,2,4]恶二唑并-[4,3-a]喹喔啉-1-酮（ODQ；10⁻⁶ M）减弱了SNP的抑制作用，但它并不影响8-溴-cGMP的抑制作用，这表明在存在D600的情况下，SNP的作用是通过环鸟苷酸的产生介导的。钙激活钾通道抑制剂大蝎毒素（10⁻⁷ M）对CCh诱导的挛缩没有影响。另一方面，在存在10⁻⁶ M D600的情况下，CCh可诱导纵行肌细胞膜去极化（从-60 mV到-45 mV），但SNP并不影响这种去极化。这些结果表明，在存在D600的情况下，SNP通过环鸟苷酸而非膜电位依赖性机制诱导豚鼠胃纵行肌CCh诱导的挛缩舒张。
