Propofol enhances GABA(A) receptor-mediated presynaptic inhibition in human spinal cord.
Although the function of somatodendritic GABAA receptors is augmented by propofol, it is not known whether presynaptic GABAA receptor function is similarly affected. In the present study, we examined the action of propofol on the second positive wave (P2 component) of segmental spinal cord evoked potentials (seg SCEPs), which is believed to reflect GABAA receptor-mediated presynaptic inhibition of primary afferent terminals and can be recorded from spinal epidural space in man. In all seven patients tested while undergoing scoliosis surgery, a clinical dose of propofol (1 mg//kg, i.v.) significantly augmented the P2 component of seg SCEPs evoked by ulner nerve stimulation. We conclude that propofol enhances GABAA receptor-mediated presynaptic inhibition at primary afferent terminals in human spinal cord.
Shimizu
Miyako
M
Department of Anesthesiology, Niigata University School of Medicine 1-757, Asahi-machi, Niigata 951-8510, Japan.
Yamakura
Tomohiro
T
Tobita
Toshiyuki
T
Okamoto
Manabu
M
Ataka
Toyofumi
T
Fujihara
Hideyoshi
H
Taga
Kiichiro
K
Shimoji
Koki
K
Baba
Hiroshi
H
D000293:Adolescent; D000778:Anesthetics, Dissociative; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D002648:Child; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007649:Ketamine; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects; D017729:Presynaptic Terminals / Q000187:drug effects; D015742:Propofol / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000187:drug effects*; D017661:Receptors, Presynaptic / Q000187:drug effects*; D012600:Scoliosis / Q000601:surgery; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects*
D000778:Anesthetics, Dissociative; D018686:Anesthetics, Intravenous; D018755:GABA Agonists; D011963:Receptors, GABA-A; D017661:Receptors, Presynaptic; D007649:Ketamine; D015742:Propofol