BETA-ENDORPHIN BUT NOT MET-ENKEPHALIN COUNTERACTS ADENOSINE-PROVOKED ANGINA PECTORIS-LIKE PAIN

WHETHER i.v. infusion of beta-endorphin or metenkephalin can modify ad enosine-provoked angina pectoris-like pain was investigated in healthy volunteers with a double-blind controlled design. All seven volunteer s experienced dose-related adenosine-provoked chest pain. Metenkephali n did not modulate the dose-effect curve for adenosine while beta-endo rphin counteracted (p < 0.01) the development of pain. The results sug gest that peripheral mu subtype opioid receptors are involved in the m odulation and may play a role in the genesis of silent and painful myo cardial ischaemia.