Opioids in Pain and Cardiovascular Responses: Overview of Common Features

Common Opioid Actions in Pain and Cardiovascular Stress Responses. This overview describes three parallel aspects of the architecture and function of opioid action in nociceptive and cardiovascular spheres. First, in both circumstances, opioid secretion and receptor activation are essentially dormant during basal conditions and assume physiological importance only during stress. Second, in either context, opioids produce their responses by activating complementary mechanisms centrally and in the periphery. Third, endorphins act as "neuromodulators" of either type of response through a typical cellular architecture in which they diminish underlying excitatory neurotransmission.