Abstract
β-Carboline-3-carboxylic acid ethyl ester (β-CCE) dose-dependently potentiated psychological-stress induced analgesia (PSY-SIA), and the effect was reversed by diazepam. Concurrent exposure to PSY stress or concomitant treatment with β-CCE blocked the development of analgesic tolerance to morphine; the effect of PSY stress was antagonized by diazepam, and that of β-CCE was reversed by Ro 15-1788. These results suggest that psychological factors which are mediated through benzodiazepine receptors are involved in the mechanism for blocking the development of analgesic tolerance to morphine by PSY stress.
