[Substituted sydnonimines: hemodynamic effects and distribution of coronary blood flow in normal and ischemic myocardium].

Some aspects of hemodynamic effects and distribution of coronary flow of molsidomine were evaluated in anesthetized dogs with open chest. Three experimental groups were performed: In groups I and II 100 micrograms/kg and 200 micrograms/kg of molsidomine were administered respectively. Cardiac output (CO), end diastolic pressure (EDP), mean arterial pressure (MAP), heart rate (HR), systolic left ventricular pressure (SLVP), their maximal rates of development and fall (+P and -P, respectively), developed tension (DT), their maximal contraction (+T) and relaxation (-T) rates, were measured. Peripheral resistance (PR) and the ratios +P/-P and +T/-T were calculated. In group III 100 micrograms/kg of molsidomine were administered after the ligature of the anterior descendent artery (AD) was performed. In this group the distribution of coronary flow was measured through radioactive microspheres injection in the circumflex area (CX) (normal area) and in the AD area (ischemic area). After injecting the microspheres and following its effects for one hour, the maximum effect was determined in 30 minutes. Heart rate did not show any statistically significant variation at any of the doses used. MAP fell from 92 +/- 3 mmHg to 77 +/- 5 mmHg (P less than 0.05) in group I and from 87 +/- 3 mmHg to 69 +/- 4 mmHg in group II. Cardiac output fell from 1.63 +/- 0.13 1/min to 1.22 +/- 0.12 1/min (P less than 0.05) in group I and from 1.60 +/- 0.19 1/min to 1.13 +/- 0.18 1/min (P less than 0.05) in group II. PR did not show any significant change in any of the groups. +P decreased 13 +/- 6% (P less than 0.05) in group I and 13 +/- 5% (P less than 0.05) in group II. The decrease of -P was of 17 +/- 5% (P less than 0.05) in both groups. EDP decreased from 6.0 +/- 1.0 mmHg to 3.9 +/- 0.9 mmHg (P less than 0.05) and from 5.5 +/- 0.5 mmHg to 2.9 +/- 0.8 mmHg (P less than 0.05) in groups I and II, respectively. DT, +T, -T, +T/-T and +P/-P did not show any significant change. EDP fell from 8 +/- 1 mmHg to 4.1 +/- 1.3 mmHg (P less than 0.05); MAP fell from 82 +/- 4 mmHg to 62 +/- 6 mmHg (P less than 0.05) and CO fell from 2.05 +/- 0.27 1/min to 1.30 +/- 0.14 1/min in group III. HR and PR did not show any significant change in group III.(ABSTRACT TRUNCATED AT 400 WORDS)