HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 292/1/R396    most recent 00776.2005v1 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 ISI 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 ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Accorsi-Mendonça, D. Articles by Machado, B. H. Search for Related Content PubMed PubMed Citation Articles by Accorsi-Mendonça, D. Articles by Machado, B. H.

NEUROHUMORAL CONTROL OF CARDIOVASCULAR FUNCTION

Urethane inhibits the GABAergic neurotransmission in the nucleus of the solitary tract of rat brain stem slices

Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil

Submitted 2 November 2005 ; accepted in final form 24 August 2006

Because urethane is a widely used anesthetic in animal experimentation, in the present study, we evaluated its effects on neurons of the nucleus of the solitary tract (NTS) in brain stem slices from young rats (25–30 days old). Using the whole cell configuration of the patch-clamp technique, spontaneous postsynaptic currents (sPSCs) and evoked excitatory postsynaptic currents (eEPSCs) were recorded. Urethane (20 mM) decreased by 60% the frequency of GABAergic sPSCs (1.0 ± 0.2 vs. 0.4 ± 0.1 Hz) but did not change the frequency, amplitude, or half-width of glutamatergic events or TTX-resistant inhibitory sPSCs [miniature inhibitory postsynaptic currents (IPSCs)]. Miniature IPSCs were measured in the presence of urethane plus 1 mM diazepam (1 mM), and no changes were seen in their amplitude. This suggests that the GABA concentration in the NTS synapses is set at saturating level. We also evaluated the effect of urethane on eEPSCs, and no significant change was observed in the amplitude of N-methyl-D-aspartate [NMDA; 44.2 ± 11.5 vs. 37.6 ± 10.6 pA (holding potential = 40 mV)] and non-NMDA currents [204.4 ± 35.5 vs. 196.6 ± 31.2 pA (holding potential = –70 mV)]. Current-clamp experiments showed that urethane did not alter the action potential characteristics and passive membrane properties. These data suggest that urethane has an inhibitory effect on GABAergic neurons in the NTS but does not change the spontaneous or evoked excitatory responses.

patch-clamp; slice; -aminobutyric acid current; neurotransmission; urethane

This article has been cited by other articles:

				S. Potez and M. E. Larkum Effect of Common Anesthetics on Dendritic Properties in Layer 5 Neocortical Pyramidal Neurons J Neurophysiol, March 1, 2008; 99(3): 1394 - 1407. [Abstract] [Full Text] [PDF]