[Effect of morphine derivatives on the function of glucocorticoid receptors in shock]

The effects of opiate receptor agonists and antagonists on the function of glucocorticoid receptors in the hepatic cytosol were examined in male Wistar rats weighing 180-240 g. With the Scatchard analysis, in vitro experiments by using labelled ligands revealed that the pure opiate agonist morphine in the wide range of concentrations (0,01-10,0 mM) failed to affect the function Type II glucocorticoid receptors, though inhibited the function of Type III glucocorticoid receptors in the dose-dependent manner. Buprenorphine and diprenorphine depressed the function of Types II and III glucocorticoid receptors. Buterphanol, an opiate receptor antagonist-agonist, like naltrexone, an opiate receptor antagonist, decreased the function of Type III glucocorticoid receptors, but modulated that of Type II glucocorticoid receptors by lowering the association constant of the ligand-Type II glucocorticoid receptor complex, but by enhancing the density of Type II glucocorticoid receptors. In vivo studies established that butorphanol dose-dependently increased the density of Type II glucocorticoid receptors in the hepatic cytosol and elevating blood pressure in rat traumatic shock. Whether glucocorticoid receptors involve in the mechanism of the antishock effect of morphine derivatives is discussed in the paper.