Zolpidem reduces the blood oxygen level-dependent signal during visual system
stimulation.
Author(s): Licata SC, Lowen SB, Trksak GH, Maclean RR, Lukas SE.
Affiliation(s): Behavioral Psychopharmacology Research Laboratory, McLean Hospital/Harvard
Medical School, 115 Mill Street, Belmont MA 02478, USA.
slicata@mclean.harvard.edu
Publication date & source: 2011, Prog Neuropsychopharmacol Biol Psychiatry. , 35(7):1645-52
Zolpidem is a short-acting imidazopyridine hypnotic that binds at the
benzodiazepine binding site on specific GABA(A) receptors to enhance fast
inhibitory neurotransmission. The behavioral and receptor pharmacology of
zolpidem has been studied extensively, but little is known about its neuronal
substrates in vivo. In the present within-subject, double-blind, and
placebo-controlled study, blood oxygen level-dependent functional magnetic
resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of
zolpidem within the brain. Healthy participants (n=12) were scanned 60 min after
acute oral administration of zolpidem (0, 5, 10, or 20mg), and changes in BOLD
signal were measured in the visual cortex during presentation of a flashing
checkerboard. Heart rate and oxygen saturation were monitored continuously
throughout the session. Zolpidem (10 and 20mg) reduced the robust visual system
activation produced by presentation of this stimulus, but had no effects on
physiological activity during the fMRI scan. Zolpidem's modulation of the BOLD
signal within the visual cortex is consistent with the abundant distribution of
GABA(A) receptors localized in this region, as well as previous studies showing a
relationship between increased GABA-mediated neuronal inhibition and a reduction
in BOLD activation.
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