title: Reversible focal ischemia in the rat: effects of halothane, isoflurane, and methohexital anesthesia.
abstract: Barbiturates and the volatile anesthetic isoflurane reduce CMR to similar values. If the mechanism of barbiturate protection against focal ischemic injury is due to a reduction in cellular energy requirements, then isoflurane should similarly reduce ischemic injury. To evaluate this, spontaneously hypertensive rats underwent 2 h of reversible middle cerebral artery occlusion (MCAO) while receiving deep methohexital, isoflurane, or halothane anesthesia. Ninety-six hours postischemia, neurologic deficits were present but without a difference between groups. Mean +/- SD infarct volume, as assessed by triphenyl tetrazolium chloride staining and computerized planimetry, was significantly less in the methohexital group (n = 8; 166 +/- 74 mm3) than in either the halothane (n = 9; 249 +/- 71 mm3; p less than 0.04) or the isoflurane (n = 9; 243 +/- 62 mm3; p less than 0.03) groups. One possible explanation for the lack of protective effect for isoflurane might be related to its vasodilative properties, which could result in a cerebral vascular steal. To examine this possibility, rats anesthetized with methohexital or isoflurane underwent autoradiographic determination of CBF with or without MCAO. In isoflurane-anesthetized sham rats (n = 5; no ischemia), CBF was approximately three times greater than in methohexital-treated (n = 5) sham rats. During ischemia, although a regional reduction in flow was noted in both anesthetic groups, mean flow remained greater in the isoflurane group.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesia, University of Iowa, Iowa City 52242.
authors.forename: D S
authors.initials: DS
authors.lastname: Warner
authors.forename: J G
authors.initials: JG
authors.lastname: Zhou
authors.forename: R
authors.initials: R
authors.lastname: Ramani
authors.forename: M M
authors.initials: MM
authors.lastname: Todd
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D006221:Halothane / Q000627:therapeutic use*; D007530:Isoflurane / Q000627:therapeutic use*; D008297:Male; D008723:Methohexital / Q000627:therapeutic use*; D051381:Rats; D011918:Rats, Inbred SHR
chemical_list: D007530:Isoflurane; D008723:Methohexital; D006221:Halothane