Effects of halothane, alpha-chloralose, and pCO2 on injury volume and CSF beta-endorphin levels in focal cerebral ischemia.
Anesthetic agent, arterial pCO2 level, and opioid peptides have all been implicated in the pathophysiology of experimental stroke models. The effects of halothane, alpha-chloralose, and differing concentrations of arterial pCO2 on injury volume and CSF beta-endorphin levels were studied in a feline model of experimental focal cerebral ischemia. The type of anesthetic agent used had no effect on injury volume following 6 h of focal cerebral ischemia. Over a 6-h period, beta-endorphin levels significantly increased from 10.1 +/- 5.0 fmol/mL at zero time to 14.4 +/- 7.2 fmol/mL at 6 h under halothane anesthesia (p < 0.05), whereas they did not significantly change (10.1 +/- 6.7 to 7.8 +/- 4.7 fmol/mL) under alpha-chloralose anesthesia. In contrast, hypercapnia had no effect on beta-endorphin levels, but significantly increased injury volume from 30.6 +/- 5.7% of the ipsilateral hemisphere under normocapnic conditions to 37.1 +/- 5.9% under hypercapnic conditions (p < 0.05). These results suggest that hypercapnia increases injury volume in a feline model of focal cerebral ischemia, and pCO2 should be controlled in experimental focal cerebral ischemia models.
Browning
J L
JL
Department of Surgery, Veteran's Affairs Medical Center, Houston, TX, USA.
Heizer
M L
ML
Widmayer
M A
MA
Baskin
D S
DS
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000473:pathology; D002245:Carbon Dioxide / Q000494:pharmacology*; D002415:Cats; D002698:Chloralose / Q000494:pharmacology*; D006221:Halothane / Q000494:pharmacology*; D002546:Ischemic Attack, Transient / Q000134:cerebrospinal fluid* / Q000473:pathology; D008297:Male; D001615:beta-Endorphin / Q000134:cerebrospinal fluid*
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D002245:Carbon Dioxide; D002698:Chloralose; D001615:beta-Endorphin; D006221:Halothane