Differences in basal endothelium-derived relaxing factor activity in different artery types.
Mechanical responses and calcium influx were measured in order to compare basal endothelium-derived relaxing factor (EDRF) activity in isolated preparations of rabbit aorta, rat aorta, and dog coronary artery. EDRF activity was characterized by endothelium-dependent mechanical relaxation and reduction of 45Ca influx which could be blocked by EDRF inhibitors. In resting preparations, the mechanical effects of basal EDRF were negligible in all preparations, and a small effect on calcium influx was demonstrated only in rat preparations. In agonist-constricted preparations, basal EDRF activity had only a small mechanical effect in rabbit preparations but markedly depressed constriction in rat and dog preparations; likewise, it had no demonstrable effect on calcium influx in rabbit preparations but had a marked effect in rat and dog preparations. In both resting and agonist-stimulated rabbit preparations, endothelium caused a cyclooxygenase product-dependent increase in calcium influx. Thus, basal EDRF activity has little or no effect in resting preparations and little or no effect in agonist-stimulated rabbit aorta preparations, but a marked effect in agonist-stimulated rat aorta and dog coronary preparations.
D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003331:Coronary Vessels / Q000378:metabolism; D004558:Electric Stimulation; D004727:Endothelium / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009569:Nitric Oxide; D011817:Rabbits; D014665:Vasodilator Agents / Q000378:metabolism*
D014665:Vasodilator Agents; D009569:Nitric Oxide; D002118:Calcium