Neurochemical Research

, Volume 34, Issue 11, pp 1896–1906

Norepinephrine Homogeneously Inhibits α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate- (AMPAR-) Mediated Currents in All Layers of the Temporal Cortex of the Rat

  • Lu Dinh
  • Tram Nguyen
  • Humberto Salgado
  • Marco Atzori
Original Paper

DOI: 10.1007/s11064-009-9966-z

Cite this article as:
Dinh, L., Nguyen, T., Salgado, H. et al. Neurochem Res (2009) 34: 1896. doi:10.1007/s11064-009-9966-z

Abstract

The primary auditory cortex is subject to the modulation of numerous neurotransmitters including norepinephrine (NE), which has been shown to decrease cellular excitability by yet unclear mechanisms. We investigated the possibility that NE directly affects excitatory glutamatergic synapses. We found that bath applications of NE (20 μM) decreased glutamatergic excitatory post-synaptic currents (EPSCs) in all cortical layers. Changes in the kinetics of synaptic EPSCs, invariance of pair pulse ratio and of the coefficient-of-variation, together with the decrease of responses to pressure-application of AMPA (500 μM), indicated the postsynaptic nature of the adrenergic effect. Pharmacological experiments suggested that the NE-induced depression of EPSCs is caused by the activation of α1 adrenoceptors, PLC, and a Ca2+-independent PKC. We speculate that the decrease in temporal cortex excitability might promote a posterior-to-anterior shift in cortical activation together with a decrease in spontaneous background activity, resulting eventually in more effective sensory processing.

Keywords

Auditory cortex Glutamate Norepinephrine PLC EPSC Patch-clamp 

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Lu Dinh
    • 1
  • Tram Nguyen
    • 1
  • Humberto Salgado
    • 1
  • Marco Atzori
    • 1
  1. 1.School of Behavioral and Brain Sciences, Laboratory of Cell and Synaptic PhysiologyThe University of Texas at DallasRichardsonUSA

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