title: Delta opioid receptors contribute to the cardiorespiratory effects of biphalin in anesthetized rats.
abstract: Biphalin expresses almost equal affinity for μ- and δ-opioid receptors. The aim of this study was to delineate a possible role of δ-opioid receptors in the cardio-respiratory effects of systemic injection of biphalin in anesthetized, spontaneously breathing rats. In control animals, an intravenous bolus of biphalin (0.3 μmol/kg) evoked apnea, followed by a decreased breathing rate and increased tidal volume, hypotension and bradycardia. Blockade of δ-opioid receptors with naltrindole (4.2 μmol/kg) significantly reduced the duration of apnea, slowdown of respiration, immediate post-challenge hypotension and bradycardia induced by biphalin administration. These results indicate that the activation of δ-opioid receptors adds to the depressive response produced by biphalin.
authors.affiliation: Laboratory of Respiratory Reflexes, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, PL 02-106 Warszawa, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Wojciechowski
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Szereda-Przestaszewska
authors.forename: Andrzej W
authors.initials: AW
authors.lastname: Lipkowski
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects; D004745:Enkephalins / Q000494:pharmacology*; D007275:Injections, Intravenous; D008297:Male; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000187:drug effects* / Q000378:metabolism; D012137:Respiratory System / Q000187:drug effects
chemical_list: D000700:Analgesics; D004745:Enkephalins; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D009271:Naltrexone; C053673:biphalin; C055382:naltrindole