title: Naloxone Antagonizes Soman-induced Central Respiratory Depression in Rats.
abstract: The influence of naloxone on respiration impaired by the highly toxic organophosphate nerve agent soman in anaesthetized rats was investigated. Soman, administered in a dose that was ineffective in blocking the electrically induced contractions of the phrenic nerve-diaphragm preparation in situ, induced a complete block of the spontaneous respiratory movements of the diaphragm, indicating the domination of central over the peripheral effects. Naloxone dose-dependently antagonized the soman-induced respiratory blockade. Atropine, at a dose that was per se ineffective in counteracting soman-induced respiratory depression, potentiated the protective effects of naloxone and completely restored respiration. Naloxone remained completely ineffective in antagonizing respiratory depression induced by the muscarinic receptor agonist the oxotremorine. It is assumed that naloxone antagonizes soman-induced respiratory inhibition by blocking endogenous opioidergic respiratory control pathways that are independent of the stimulation of muscarinic receptors.
authors.affiliation: Department of Pharmacology & Toxicology, Medical Faculty, University of Banja Luka, Banja Luka, Republic of Srpska, Bosnia & Herzegovina.
authors.forename: Ranko
authors.initials: R
authors.lastname: Škrbić
authors.affiliation: Department of Pharmacology & Toxicology, Medical Faculty, University of Banja Luka, Banja Luka, Republic of Srpska, Bosnia & Herzegovina.|Military Medical Academy, Belgrade, Serbia.
authors.forename: Miloš P
authors.initials: MP
authors.lastname: Stojiljković
authors.affiliation: Military Medical Academy, Belgrade, Serbia.
authors.forename: Slavko S
authors.initials: SS
authors.lastname: Ćetković
authors.affiliation: Military Medical Academy, Belgrade, Serbia.
authors.forename: Silva
authors.initials: S
authors.lastname: Dobrić
authors.affiliation: Department of Anatomy and Forensic Medicine, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia.
authors.forename: Dejan
authors.initials: D
authors.lastname: Jeremić
authors.affiliation: Department of Anatomy and Forensic Medicine, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Vulović
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D000067397:Nerve Agents / Q000633:toxicity*; D010095:Oxotremorine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000187:drug effects; D012131:Respiratory Insufficiency / Q000139:chemically induced / Q000188:drug therapy*; D012999:Soman / Q000037:antagonists & inhibitors* / Q000633:toxicity
chemical_list: D000067397:Nerve Agents; D011976:Receptors, Muscarinic; D009270:Naloxone; D010095:Oxotremorine; D001285:Atropine; D012999:Soman