Inotropic and electrophysiological effects of histamine on human ventricular heart muscle.

Publisher Website
Google Scholar
Abstract
The effects of histamine were investigated on mechanical and electrophysiological parameters in isolated electrically driven human ventricular papillary muscles. The effects of cimetidine and propranolol on histamine responses were also investigated. The effects of histamine were compared with those of noradrenaline [norepinephrine], isoprenaline, dimaprit, a selective H2-receptor agonist, and a cAMP derivative, 8-(4-chlorphenylthio) cAMP. The effects of histamine and dimaprit and the effects of cimetidine on histamine responses were also investigated in guinea-pig right ventricular papillary muscles in order to allow a comparison with human papillary muscles. In human papillary muscles, histamine caused concentration-dependent increases in the force of contraction and reductions in both time-to-peak tension and time-to-half-maximal relaxation. Histamine simultaneously caused distinct changes in the action potential configuration with increases in the height and duration of the plateau phase and an increase in the overall action potential duration. Noradrenaline and isoprenaline produced similar responses to histamine, as did 8-(4-chlorphenylthio) cAMP, consistent with the view that the effects of histamine as well as the .beta.-adrenoceptor agonists on human ventricle, were associated with cAMP mediated increases in Ca-dependent slow inward current.

This publication has 2 references indexed in Scilit: