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A study of the actions of histamine on the isolated rat heart
Author(s) -
Dai Soter
Publication year - 1976
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1976.tb00612.x
Subject(s) - metiamide , chronotropic , histamine , diphenhydramine , heart rate , perfusion , inotrope , coronary perfusion pressure , medicine , blood pressure , anesthesia , cardiology , chemistry , endocrinology , receptor , histamine h2 receptor , antagonist , cardiopulmonary resuscitation , resuscitation
SUMMARY 1. The effects of histamine on cardiac force, heart rate and coronary perfusion pressure were studied in the isolated rat heart, using the Langendorff perfused heart preparation. 2. Single injections of histamine induced dose‐dependent decreases in contractile amplitude, heart rate and coronary perfusion pressure. 3. Perfusions of metiamide (above 1 × 10 ‐4 M) had a depressant effect on contractile force and heart rate, whereas diphenhydramine (4 × 10 ‐6 M) reduced only the heart rate. Both agents caused a fall in coronary perfusion pressure. 4. The negative inotropic and chronotropic effects of histamine on the isolated rat heart were not significantly influenced by either metiamide or diphenhydramine, or a combination of these drugs. However, the fall in coronary perfusion pressure induced by injections of histamine was significantly antagonized by metiamide or diphenhydramine. 5. These results suggest that the effects of histamine on the isolated rat heart may not be due entirely to stimulation of H 1 ‐ or H 2 ‐receptors on the cardiac muscle cells. Evidence is presented for the existence of histamine H 1 ‐ and H 2 ‐receptors in the coronary vessels.