Effect of preischemia cyclooxygenase inhibition by zomepirac sodium on reflow, cerebral autoregulation, and EEG recovery in the cat after global ischemia.
Zomepirac sodium (ZS) (5 mg/kg i.v.) was used to evaluate the effects of preischemia cyclooxygenase inhibition on CBF (as assessed by 133Xe clearance), CBF-PaCO2 responsiveness, and electrophysiologic (EEG) parameters before and after a 15-min period of complete global ischemia produced by four-vessel occlusion and mild hypotension. During the 15-min period of ischemia, CBF was essentially zero. Following reflow all groups displayed an initial hyperemia as compared with control (92 +/- 11 vs. 141-146 ml/100 g/min). Saline-treated animals during reflow displayed a delayed hypoperfusion (26 +/- 3 ml/100 g/min), which showed no improvement during the 2-h reflow period prior to death. In contrast, ZS-treated animals during reflow displayed significantly higher flows during the hypoperfusion phase (72 +/- 9 ml/100 g/min). The CBF-PaCO2 response displayed an approximately sevenfold reduction in slope at 2 h after reflow in saline-treated animals. This decrease in PaCO2 reactivity was not observed in the ZS-pretreated animals. With regard to EEG, all animals showed a total flattening during the 15 min of ischemia. In saline-treated animals only one of seven showed any sign of even marginal recovery. In ZS-treated animals EEG activity showed prominent recovery in seven of seven. Brainstem auditory evoked potentials were monitored and showed prominent recovery of amplitude and latency in ZS but not saline-treated animals during reflow.
D000818:Animals; D001921:Brain / Q000503:physiopathology*; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D016861:Cyclooxygenase Inhibitors; D004569:Electroencephalography; D005260:Female; D006706:Homeostasis; D002546:Ischemic Attack, Transient / Q000134:cerebrospinal fluid / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D011453:Prostaglandins / Q000134:cerebrospinal fluid; D011758:Pyrroles / Q000494:pharmacology*; D014046:Tolmetin / Q000031:analogs & derivatives / Q000494:pharmacology*
D016861:Cyclooxygenase Inhibitors; D011453:Prostaglandins; D011758:Pyrroles; C020549:zomepirac; D014046:Tolmetin