title: Do nitrous oxide and halothane influence opioid receptor binding in SH-SY5Y human neuroblastoma cells?
abstract: The site of interaction of opioids and inhalation anaesthetic agents is unknown, but may be at the level of the opioid receptor. In this study we have used SH-SY5Y human neuroblastoma cells, which express both mu and delta receptors, to examine the effects of halothane on the receptor binding profiles of [3H]diprenorphine (DPN), an opioid receptor antagonist, and [3H] [D-Ala2,MePhe4, Gly(ol)5]enkephalin (DAMGO), a mu receptor selective agonist. Binding of [3H]DPN and [3H]DAMGO was performed at 37 degrees C for 60 min in the presence of air, nitrous oxide (75%) or air containing halothane (0.5-5.0% v/v). Compared with air controls, neither 75% nitrous oxide nor 0.5, 1.0, 2.0 and 5.0% halothane influenced DPN binding variables. Binding of [3H]DAMGO was unaffected by 1.0% halothane, but 5.0% halothane reduced the affinity, with a modest increase in Kd (1.15 (0.16) to 1.7 (0.2) nmol litre-1) without effect on Bmax. Our data suggest that the site of opioid and volatile anaesthetic interaction is not at the opioid receptor.
authors.affiliation: University Department of Anaesthesia, Leicester Royal Infirmary.
authors.forename: D J
authors.initials: DJ
authors.lastname: Campbell
authors.forename: D J
authors.initials: DJ
authors.lastname: Rowbotham
authors.forename: D G
authors.initials: DG
authors.lastname: Lambert
mesh_terms: D000700:Analgesics / Q000378:metabolism; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D004174:Diprenorphine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000378:metabolism; D006221:Halothane / Q000494:pharmacology*; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism; D009609:Nitrous Oxide / Q000494:pharmacology*; D011957:Receptors, Opioid / Q000187:drug effects* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000700:Analgesics; D018685:Anesthetics, Inhalation; D004745:Enkephalins; D011957:Receptors, Opioid; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004174:Diprenorphine; D009609:Nitrous Oxide; D006221:Halothane