title: Depressive effect of isoflurane anesthesia on motor evoked potentials.
abstract: The influence of the volatile anesthetic isoflurane (Forane) on motor evoked potentials was examined in rats. To record motor evoked potentials, single-shock electrical stimulation was delivered to the forelimb representation of the motor cortex. This resulted in elicitation of a compound muscle action potential from the contralateral extensor muscles. The effect of isoflurane was examined at various concentrations ranging from 0.2 to 1.5%. With increasing concentrations of isoflurane there was a progressive increase in onset latency of the compound muscle action potential and a decrease in peak-to-peak amplitude and duration. Latencies were significantly increased over baseline values for concentrations of isoflurane from 0.5 to 1.5% (P values were 0.001 to 0.007). For the amplitude and the duration, responses at 0.5 to 1.5% isoflurane were significantly lower than baseline (P values were 0.001 to 0.007). We conclude that isoflurane anesthesia significantly changes the muscle response evoked by motor cortex stimulation in experimental animals.
authors.affiliation: Division of Neurosurgery, University of Missouri-Columbia Hospital and Clinics.
authors.forename: S S
authors.initials: SS
authors.lastname: Haghighi
authors.forename: K D
authors.initials: KD
authors.lastname: Green
authors.forename: J J
authors.initials: JJ
authors.lastname: Oro
authors.forename: R K
authors.initials: RK
authors.lastname: Drake
authors.forename: G R
authors.initials: GR
authors.lastname: Kracke
mesh_terms: D000758:Anesthesia / Q000009:adverse effects*; D000818:Animals; D003864:Depression, Chemical; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D009044:Motor Cortex / Q000187:drug effects*; D009132:Muscles / Q000502:physiology*; D009609:Nitrous Oxide / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time
chemical_list: D007530:Isoflurane; D009609:Nitrous Oxide