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*Department of Anesthesia and Perioperative Care, University of California, San Francisco; and
Department of Psychology, University of California, Los Angeles
Address correspondence and reprint requests to James M. Sonner, MD, Department of Anesthesia, S-455, University of California, San Francisco, CA 94143-0464. Address e-mail to sonnerj{at}anesthesia.ucsf.edu.
Previous reports suggest that the administration of epinephrine increases learning during deep barbiturate-chloral hydrate anesthesia in rats but not during anesthesia with 0.4% isoflurane in rabbits. We revisited this issue, using fear conditioning to a tone in rats as our experimental model for learning and memory and isoflurane and desflurane as our anesthetics. Expressed as a fraction of the minimum alveolar anesthetic concentration (MAC) preventing movement in 50% of rats, the amnestic 50% effective dose (ED50) for fear to tone in control rats inhaling isoflurane and injected with saline intraperitoneally (i.p.) was 0.32 ± 0.03 MAC (mean ± se) compared with 0.37 ± 0.06 MAC in rats injected with 0.01 mg/kg of epinephrine i.p. and 0.38 ± 0.03 MAC in rats injected with 0.1 mg/kg of epinephrine i.p. For desflurane, the amnestic ED50 were 0.32 ± 0.05 MAC in control rats receiving a saline injection i.p. versus 0.36 ± 0.04 MAC in rats injected with 0.1 mg/kg of epinephrine i.p. We conclude that exogenous epinephrine does not decrease amnesia produced by inhaled isoflurane or desflurane, as assessed by fear conditioning to a tone in rats.
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R. Brosnan, D. Gong, J. Cotten, B. Keshavaprasad, C. S. Yost, E. I. Eger II, and J. M. Sonner Chirality in Anesthesia II: Stereoselective Modulation of Ion Channel Function by Secondary Alcohol Enantiomers. Anesth. Analg., July 1, 2006; 103(1): 86 - 91. [Abstract] [Full Text] [PDF] |
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