Depolarization regulates selectively the expression of different opioid receptors: a decreased number of kappa receptors in chronically activated guinea pig brain cell cultures.
Previous studies about the differential effect of chronic membrane depolarization on the expression of mu and delta opioid receptors prompted us to investigate whether the same treatment regulates also the expression of kappa opioid receptors. Embryonic guinea pig brain cells that exhibit in culture a high density of kappa receptors were treated for different time periods with potassium chloride, and the number of these receptors was determined with the universal opioid ligand [3H]diprenorphine. In a second set of experiments the cultures were treated with the sodium channel activator veratridine and opioid receptors were determined with the selective kappa ligand [3H]U69,593. The results indicate that chronic membrane depolarization (for 3 or 6 days) decreases significantly the number of kappa receptors, with no effect on the affinity of the ligands. Taken together with our previous reports, it is suggested that neuronal activation has a selective and possibly opposite regulatory role on the expression of the 3 opioid receptors.
Barg
J
J
Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel.
Simantov
R
R
D000818:Animals; D044482:Benzeneacetamides; D001921:Brain / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D004174:Diprenorphine / Q000378:metabolism; D005786:Gene Expression Regulation; D006168:Guinea Pigs; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology; D011759:Pyrrolidines / Q000378:metabolism; D011957:Receptors, Opioid / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D017473:Receptors, Opioid, kappa
D044482:Benzeneacetamides; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D004174:Diprenorphine; C045444:U 69593; D011188:Potassium