de Hurtado M C, Cingolani H E
Acta Physiol Lat Am. 1983;33(3):223-9.
The effects of nitroglycerin and SIN-1 on atrial rate and intracellular levels of cGMP were studied in the isolated spontaneously beating rat atria. Basal atrial rate was 254 +/- 5 beats X min-1 in the group of experiments performed with SIN-1 and 276 +/- 8 beats X min-1 in that performed with nitroglycerin. No chronotropic effect was detected when nitroglycerin or SIN-1 were added in concentrations ranging from 10(-11)M to 10(-4)M. Measurements of cGMP levels showed that the nucleotide content of atrial tissue increased from a control value of 46.98 +/- 12.1 fmol X mg-1 (w.w.) to 86.4 +/- 3.2 fmol X mg-1 with 10(-5)M SIN-1 and to 107.6 +/- 12.2 fmol X mg-1 with 10(-5)M nitroglycerin (P less than 0.05). The data show no alteration in the chronotropic activity despite the increments in cGMP levels, probably due to an uncoupling between the guanylate cyclase sensitive to SIN-1 and nitroglycerin and the cGMP dependent protein kinase.
在离体自发搏动的大鼠心房中研究了硝酸甘油和SIN-1对心房率及细胞内cGMP水平的影响。在用SIN-1进行的实验中，基础心房率为254±5次/分钟，在用硝酸甘油进行的实验中为276±8次/分钟。当加入浓度范围为10⁻¹¹M至10⁻⁴M的硝酸甘油或SIN-1时，未检测到变时作用。cGMP水平的测量表明，心房组织的核苷酸含量从对照值46.98±12.1 fmol/mg（湿重）增加到10⁻⁵M SIN-1时的86.4±3.2 fmol/mg，以及10⁻⁵M硝酸甘油时的107.6±12.2 fmol/mg（P<0.05）。尽管cGMP水平升高，但数据显示变时活性没有改变，这可能是由于对SIN-1和硝酸甘油敏感的鸟苷酸环化酶与cGMP依赖性蛋白激酶之间的解偶联所致。
