Response to histamine of the intact coronary system in an isolated rabbit heart preparation.
In isolated Langendorff-perfused rabbit hearts concentration-response relations for histamine were analysed with and without H2-receptor blocker cimetidine (10(-5) mol l-1). The diameter of large epicardial coronary arteries was determined by video angiometry. Global coronary flow and left ventricular isovolumetric pressure were continuously registered. Histamine concentration (10(-7)-6 X 10(-6) mol l-1) reduced the diameter of large coronary arteries up to -50%, however, this vasoconstriction was maximal after 1 min and was then attenuated within the following 20 min. Coronary flow and left ventricular pressure were not significantly altered. In the presence of cimetidine the histamine-induced vasoconstriction was stabilized and not reversed with time. Moreover, the extent of vessel wall narrowing was intensified (up to -70%) when compared with histamine alone. Furthermore, severe functional myocardial failure was observed (flow reduction to 40% of control).
Rösen
R
R
Pharmakologisches Institut der Universität zu Köln, F.R.G.
Hegner-Mai
M
M
Klaus
W
W
D000818:Animals; D002927:Cimetidine / Q000494:pharmacology; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000187:drug effects*; D006632:Histamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D011817:Rabbits; D014661:Vasoconstriction / Q000187:drug effects*
D002927:Cimetidine; D006632:Histamine