ONTOGENY, GLYCOSYLATION AND MODULATION BY DIALYSIS, SODIUM AND NUCLEOTIDES OF THE RAT-BRAIN DELTA-OPIOID RECEPTOR STUDIED WITH ANTIIDIOTYPIC ANTIBODIES TO ANTI-LEUCINE ENKEPHALIN

Ontogeny of the rat brain delta opioid receptor in 1-60 days old anima ls has been studied with anti-idiotypic antibodies to anti-leucine enk ephalin. It is found that delta opioid receptors are present in rats f rom birth and attain adult levels by 28 days and these receptors are g lycosylated and inhibited by Na+, GTP, ATP and CTP at all ages. Adult membrane-bound and solubilized delta opioid receptors are inhibited to similar extents by Na+ (100 mM), GTP, ATP and CTP (50 mu M). Dialysis of the adult membrane-bound receptor led to 81% loss in binding which was restored by 100 mM Na+, 50 mu M GTP, ATP and CTP to 77, 72, 87 an d 94% respectively and by 100 mM NH4+, Mg2+, and Mn2+ to 63, 43, 57 an d 73% respectively. Dialysis of the solubilized receptor resulted in 2 3% loss in binding with Na+ (100 mM), GTP and ATP (50 mu M) inhibiting receptor binding to 46, 62 and 54% respectively, while CTP (50 mu M) restored binding to 88%. These studies indicate that the delta opioid receptor can be probed with anti-idiotypic antibodies to anti-leucine enkephalin, that functional, glycosylated receptors are present at bir th in rats and that the adult membrane-bound and solubilized receptors are modulated differently by dialysis.