Mirzazadeh S, Hobbs A J, Tucker J F, Gibson A
Smooth Muscle Pharmacology Group, King's College London, UK.
J Pharm Pharmacol. 1991 Apr;43(4):247-51. doi: 10.1111/j.2042-7158.1991.tb06677.x.
Low concentrations of sodium nitroprusside (0.2 and 1 microM) relaxed carbachol-induced tone of the rat anococcygeus but did not affect the content of either cGMP or cAMP; higher concentrations (10,100 and 1000 microM) produced greater relaxation (greater than 60%) and a rise in cGMP but not cAMP. In the presence of the cGMP-phosphodiesterase inhibitor M&B 22948 (10 microM), 1 microM sodium nitroprusside produced greater relaxation and a selective increase in cGMP. Forskolin (0.5-250 microM) caused relaxation and a selective increase in cAMP; the concentration-response relationships of the two effects were similar. Non-adrenergic, non-cholinergic (NANC) field stimulation (10 Hz; 20 s trains) reduced tone by 52% but had no effect on cyclic nucleotide content; in the presence of 10 microM M&B 22948 or 1 microM sodium nitroprusside, NANC stimulation produced a greater degree of relaxation and increased cGMP but not cAMP content. The results show that NANC stimulation acts like sodium nitroprusside, causing a selective increase in cGMP, and this supports the proposal that NANC transmission in the rat anococcygeus involves an endogenous nitrate; the possibility that multiple pools of cGMP exist in the anococcygeus is discussed.
低浓度的硝普钠（0.2和1微摩尔）可舒张卡巴胆碱诱导的大鼠肛门尾骨肌张力，但不影响环鸟苷酸（cGMP）或环磷酸腺苷（cAMP）的含量；较高浓度（10、100和1000微摩尔）可产生更大程度的舒张（大于60%）并使cGMP升高，但不影响cAMP。在存在cGMP磷酸二酯酶抑制剂M&B 22948（10微摩尔）的情况下，1微摩尔硝普钠可产生更大程度的舒张并使cGMP选择性增加。福斯高林（0.5 - 250微摩尔）可引起舒张并使cAMP选择性增加；这两种效应的浓度 - 反应关系相似。非肾上腺素能、非胆碱能（NANC）场刺激（10赫兹；20秒串刺激）可使张力降低52%，但对环核苷酸含量无影响；在存在10微摩尔M&B 22948或1微摩尔硝普钠的情况下，NANC刺激可产生更大程度的舒张并增加cGMP含量，但不影响cAMP含量。结果表明，NANC刺激的作用类似于硝普钠，可使cGMP选择性增加，这支持了大鼠肛门尾骨肌中NANC传递涉及内源性硝酸盐的观点；文中还讨论了肛门尾骨肌中存在多个cGMP池的可能性。
