Orthostatic influences on cardiovascular responses to nitroglycerin in conscious dogs.

The influence of body position change on the arterial pressure and heart rate responses produced by acute short-acting and sustained-release dosage forms of nitroglycerin was evaluated in a series of chronically prepared, conscious beagle dogs. The upright repositioning of the dog to 60 degrees from horizontal markedly enhanced the hypotensive and bradycardic responses produced by both dosage forms. Since it has been suggested that the lowering of arterial pressure is an essential component resulting in the therapeutic usefulness of nitroglycerin in angina pectoris, the experimental orthostatic model could be a sensitive procedure for the laboratory assessment of drugs of this class.