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Effects of naloxone and morphine on cerebral ischemia in gerbils
Author(s) -
ChristiePope B.C.,
Palmer G.C.,
Palmer S.J.
Publication year - 1986
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490160409
Subject(s) - (+) naloxone , morphine , ischemia , anesthesia , medicine , pharmacology , neuroscience , psychology , opioid , receptor
Abstract A therapeutic role for naloxone during stroke has been suggested, but a neurochemical site of action remains to be determined. Previous work with the geerbil cerebral cortex has shown that either bilateral secondary ischemia (60‐min occlusion of the carotid arteries followed by 40‐min reflow) or unilateral primary ischemia (permanent ligation of one carotid artery for 6 hr in symptomatic animals) produced deficits in both Na + , K + ‐ATPase (EC 3.6.1.3) activity and various parameters of activation of adenylate cyclase (EC 4.6.1.1). Pretreatment of gerbils with either naloxone or morphine failed to ameliorate or exacerbate, respectively, the neurological signs of ischemia; however, morphine did reduce mortality. Infusion of naloxone prior to ischemia afforded varying degrees of protection to forskolin, GTP analogs, and NE (norepinephrine) activation of adenylate cyclase, as well as to Na + , K + ‐ATPase (bilateral ischemia only). Similarly, morphine inhibited damage to basal activity of adenylate cyclase and to stimulation by NE, forskolin, and Gpp (NH)p (5′‐guanylyl imidodiphosphate). Under in vitro conditions morphine increased the basal activity of adenylate cyclase but reduced responses to NE and forskolin. Furthermore, morphine injected into control gerbils elevated basal‐ and forskolin‐elicited activities but reduced the activation of adenylate cyclase by NE.