Harada N, Chijiiwa Y, Akiho H, Okabe H, Nawata H
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Digestion. 1996;57(2):79-82. doi: 10.1159/000201317.
Smooth muscle cells isolated from cecal circular smooth muscle of the guinea pig were used to determine whether thyrotropin-releasing hormone (TRH) can inhibit the contractile response produced by 10(-6) M carbachol by exerting a direct action on muscle cells. In addition, the inhibitory effect of 2',5'-dideoxyadenosine (an inhibitor of adenylate cyclase), phorbol 12-myristate 13-acetate (an inhibitor of particulate guanylate cyclase), 6-anilinoquinoline-5,8-quinone (an inhibitor of nitric oxide synthase) on the TRH-induced relaxation of cecal circular smooth muscle cells was examined. TRH inhibited the contractile response produced by 10(-6) M carbachol in a concentration-dependent manner, with an IC50 value of 4 nM, 2',5'-Dideoxyadenosine and phorbol 12-myristate 13-acetate did not have any significant effect on the TRH-induced relaxation. On the other hand, 6-anilinoquinoline-5,8-quinone and N omega-nitro-L-arginine methyl ester significantly inhibited the relaxation produced by TRH. Our findings show that TRH has a direct inhibitory effect on the isolated cecal circular smooth muscle cells via activation of nitric oxide synthase and soluble guanylate cyclase.
从豚鼠盲肠环行平滑肌中分离出的平滑肌细胞，用于确定促甲状腺激素释放激素（TRH）是否可通过对肌肉细胞发挥直接作用，来抑制由10⁻⁶ M卡巴胆碱产生的收缩反应。此外，还检测了2',5'-二脱氧腺苷（一种腺苷酸环化酶抑制剂）、佛波醇12-肉豆蔻酸酯13-乙酸酯（一种颗粒型鸟苷酸环化酶抑制剂）、6-苯胺基喹啉-5,8-醌（一种一氧化氮合酶抑制剂）对TRH诱导的盲肠环行平滑肌细胞舒张的抑制作用。TRH以浓度依赖的方式抑制10⁻⁶ M卡巴胆碱产生的收缩反应，IC50值为4 nM，2',5'-二脱氧腺苷和佛波醇12-肉豆蔻酸酯13-乙酸酯对TRH诱导的舒张没有任何显著影响。另一方面，6-苯胺基喹啉-5,8-醌和Nω-硝基-L-精氨酸甲酯显著抑制TRH产生的舒张。我们的研究结果表明，TRH通过激活一氧化氮合酶和可溶性鸟苷酸环化酶，对分离出的盲肠环行平滑肌细胞具有直接抑制作用。
