R. Evans, J. Ludbrook, Jan Michalicek
Sep 1, 1990
Citations
3
Influential Citations
41
Citations
Quality indicators
Journal
Clinical and Experimental Pharmacology and Physiology
Abstract
1. When phenylbiguanide (1‐PBG) (6.25–400 μg) was injected into the left atrium, right atrium or pulmonary artery of unanaesthetized rabbits it caused dose‐dependent falls of heart rate and arterial pressure, and short‐lived hypopnoea or apnoea. The threshold dose was 50–100 μg. Maximal falls of heart rate (86–108 beats/min) and arterial pressure (33–35 mmHg) occurred at a dose of 200 μg. The latency between injection and onset of the bradycardia was 2.2–2.6 s and did not depend on the route. Cardiac output fell transiently with heart rate, but at the time of the maximal fall of arterial pressure it had returned to normal. All effects were abolished by intrapericardial procaine. The haemodynamic effects were exaggerated by sino‐aortic barodenervation. Intrapericardial 1‐PBG (200–400 μg) was without effect. Injection of 1‐PBG (>50–100 μg) into the aortic arch caused a variable increase in heart rate and arterial pressure.