Lack of glibenclamide or TEA affinity for opioid receptors: further evidence for in vivo modulation of antinociception at K+ channels.
Radioligand binding of the opioid receptor subtype selective ligands, [3H][D-Ala2,N-Me-Phe4, Gly-ol5]-enkephalin (DAMGO) (mu), [3H][D-Pen2,D-Pen5]-enkephalin (DPDPE) (delta) and [3H]U-69,593 (kappa), to rat brain particulate preparations was virtually unaffected by 1-100 microM glibenclamide (Glib) or tetraethylammonium bromide (TEA). These results argue against opioid receptor antagonism by Glib or TEA and support the hypothesis that antagonism of opioid-induced antinociception by Glib or TEA occurs at the level of K+ (possibly ATP-sensitive KATP) channels.
R. W. Johnson Pharmaceutical Research Institute, Spring House, PA 19477-0776.
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D000595:Amino Acid Sequence; D000818:Animals; D005905:Glyburide / Q000494:pharmacology*; D008297:Male; D008969:Molecular Sequence Data; D010146:Pain / Q000503:physiopathology*; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects*; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000187:drug effects* / Q000378:metabolism; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology*
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D011957:Receptors, Opioid; D013757:Tetraethylammonium Compounds; D019789:Tetraethylammonium; D005905:Glyburide