Endogenous opioid system activity following temporary focal cerebral ischemia.
We studied changes in opioid receptors (mu, delta, kappa) concentrations during temporary middle cerebral artery occlusion (MCAO) in cats by sequential displacement of unselective opioid antagonist, [3H]-diprenorphine with highly selective ligands for mu, delta and kappa, subsites. Following threshold cerebral ischemia (rCBF < 10 ml/100 g/min) there was a 2 to 3 fold increase in the 3 opioid receptor subtype concentrations at 10 min following the release of MCAO. Further, 56% of the cats depicted early postischemic hyperemia BBB opening, at 1 h and 3 h following the release of occlusion, with significant subsequent progression of brain edema. We believe that the enhanced brain opioid activity may be relevant to the neuronal damage caused by the early postischemic BBB opening.
Department of Pediatrics, College of Medicine, Howard University, Washington, DC.
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D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology; D001921:Brain / Q000098:blood supply; D001929:Brain Edema / Q000503:physiopathology*; D002415:Cats; D004174:Diprenorphine / Q000493:pharmacokinetics; D002546:Ischemic Attack, Transient / Q000503:physiopathology*; D008297:Male; D009410:Nerve Degeneration / Q000502:physiology; D018847:Opioid Peptides / Q000502:physiology*; D011957:Receptors, Opioid / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D015427:Reperfusion Injury / Q000503:physiopathology
D018847:Opioid Peptides; D011957:Receptors, Opioid; D004174:Diprenorphine