Regulation of Human Internal Mammary and Radial Artery Contraction by Extracellular and Intracellular Calcium Channels and Cyclic Adenosine 3′, 5′ Monophosphate

Our findings suggest that thromboxane A2 receptor-dependent pathways activate contraction of IMA and RA through both extracellular Ca2+-dependent and Ca2+-independent pathways. In addition, adenylate cyclase appears to play a key role in attenuating thromboxane A2 and α-adrenergic receptor-mediated contraction through both pathways.