Aim: To study the effects of pyrimidine derivative 4CPTP on cardiovascular system. Material and methods: Ionotropic and chronotropic effects of 4CPTP were studied using rabbit heart and frog’s heart ‘in situ’ preparation. Dog’s blood pressure preparation was used to assess the effects of 4CPTP on blood pressure. Results: The test compound, like phenobarbitone produced dose dependent decrease in...

ERNAU 25 Interference with Excitation by 5-Benzoyloxy-2-Iminohexahydropyrimidine Hydrochloride. M. Y. SPIEGELSTEIN AND C. Y. KAO 34 Negative Chronotropic Effects of McN A-343 and Nicotine in Isolated Guinea-Pig Atria: Insensitivity to Blockade by Tetrodotoxin. ACHILLES J. PAPPANO AND ROBERT A. REMBISH 40 Ganglionic Stimulation: Mechanism of the Positive Inotropic and Chronotropic Effects of Ang...

The relationship between heart rate (HR) during exercise and exercise capacity in patients with heart failure due to left ventricular systolic dysfunction remains unclear. The accepted diagnostic criterion for chronotropic incompetence (CI), a maximum agepredicted heart rate (MA-PHR) 85%, is seen in 50% of patients with severe heart failure on contemporary medical therapy (1). Whether the lesse...

Twelve healthy volunteers were given one week's oral treatment with each of 300 mg nizatidine, 40 mg famotidine, and placebo once daily in a randomised, placebo controlled, double blind study. Three hours after administration, nizatidine led to a significant reduction in the mean (SD) resting heart rate compared with placebo (63.6 (6.4) beats/minute on placebo to 55.9 (7.2) beats/minute on niza...

Background: There are controversial reports about the exact mechanisms of lead-induced hypertension, but many factors such as alteration in the responsiveness of cardiovascular system to endogenous substances including catecholamines could be one of the mechanisms involved. In present study, the effect of exposure to 100 ppm lead acetate by drinking water (in the periods of 4, 8 and 12 weeks)...

The effects of potassium chloride on inotropic and chronotropic activity were investigated in five isolated canine atrium preparations which were suspended in a bath and perfused with arterial blood from the carotid artery of the heparinized support dog. Potassium chloride administered into the cannulated sinus node artery in a dose range of 100 mug-1 mg produced a dose-related negative inotrop...

The cardiac effects of magnesium were studied on 40 spontaneously beating rabbit atria at 37 degrees C. Magnesium administered in doses of 30, 60, 120 and 240 mmol elicited dose dependent negative inotropic and chronotropic responses. Larger doses above 240 mmol caused complete atrial arrest. Further it was observed that propranolol with magnesium became more effective in blocking the positive ...

ERNAU 25 Interference with Excitation by 5-Benzoyloxy-2-Iminohexahydropyrimidine Hydrochloride. M. Y. SPIEGELSTEIN AND C. Y. KAO 34 Negative Chronotropic Effects of McN A-343 and Nicotine in Isolated Guinea-Pig Atria: Insensitivity to Blockade by Tetrodotoxin. ACHILLES J. PAPPANO AND ROBERT A. REMBISH 40 Ganglionic Stimulation: Mechanism of the Positive Inotropic and Chronotropic Effects of Ang...