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This Article Full Text Full Text (PDF) All Versions of this Article: 92/3/1479    most recent 01108.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Taepavarapruk, N. Articles by Soja, P. J. Search for Related Content PubMed PubMed Citation Articles by Taepavarapruk, N. Articles by Soja, P. J.

State-Dependent GABAergic Inhibition of Sciatic Nerve-Evoked Responses of Dorsal Spinocerebellar Tract Neurons

Faculty of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, The University of British Columbia, Vancouver V6T 1Z3, Canada

Submitted 17 November 2003; accepted in final form 15 April 2004

Peripheral nerve-evoked potentials recorded in the cerebellum 35 yr ago inferred that sensory transmission via the dorsal spinocerebellar tract (DSCT) is reduced occasionally and only during eye movements of active sleep compared with wakefulness or quiet sleep. A reduction or withdrawal of primary afferent input and/or ongoing inhibition of individual lumbar DSCT neurons may underlie this occurrence. This study distinguished between these possibilities by examining whether peripheral nerve-evoked responses recorded from individual DSCT neurons are suppressed specifically during active sleep, and if so, whether GABA mediates this phenomenon. Synaptic responses to threshold stimuli applied to the sciatic nerve were characterized by a single spike response at short latency and/or a longer latency burst of action potentials. During the state of quiet wakefulness, response magnitude did not differ from that observed during quiet sleep. During active sleep, short and long latency responses were suppressed by 26 and 14%, respectively, and returned to pre-active sleep levels following awakening from active sleep. Sciatic nerve-evoked early and late responses were further analyzed in a paired fashion around computer-tagged eye movement events that hallmark the state of active sleep. Response magnitude was suppressed by 14.4 and 11.5%, respectively, during eye movement events of active sleep. The GABA_A antagonist bicuculline, applied juxtacellularly by microiontophoresis, abolished response suppression during non–eye movement periods and eye movement events of active sleep. In conclusion, synaptic transmission via DSCT neurons is inhibited by GABA tonically during non–eye movement periods and phasically during eye movement events of active sleep.

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				N. Taepavarapruk, P. Taepavarapruk, J. John, Y. Y. Lai, J. M. Siegel, A. G. Phillips, S. A. McErlane, and P. J. Soja State-Dependent Changes in Glutamate, Glycine, GABA, and Dopamine Levels in Cat Lumbar Spinal Cord J Neurophysiol, August 1, 2008; 100(2): 598 - 608. [Abstract] [Full Text] [PDF]