Experimental Brain Research

, Volume 118, Issue 3, pp 361–372

Effects of noradrenaline on rate-level function of auditory cortex neurons: Is there a “gating” effect of noradrenaline?

  • Yves Manunta
  • J.-M. Edeline

DOI: 10.1007/s002210050290

Cite this article as:
Manunta, Y. & Edeline, JM. Exp Brain Res (1998) 118: 361. doi:10.1007/s002210050290


 To test a potential “gating” effect of noradrenaline (NA) in the auditory cortex, the acoustic threshold was estimated by determining the rate-level function of neurons before, during, and after microiontophoretic application (5–40 nA) of NA. The rationale behind this experiment was that a gating effect should decrease the threshold for acoustic excitatory responses. From 84 recorded neurons, we observed (1) that application of NA increased the threshold for 48 of 84 cells, and (2) that, on average, the slope of the rate-level functions was unchanged. These effects on the threshold are consistent with the fact that the dominant effect of NA on the evoked response is inhibition for 34 of 84 cells; increases in evoked responses were observed for only 14 of 84 cells. GABA application (0–50 nA) also led to increased response threshold for 19 of 24 cells (unaffected, 5 of 24 cells). However, for three cells the effect of GABA application was antagonized by bicuculline application, while on the same cells bicuculline application did not prevent the noradrenergic increase in threshold. The effect induced by NA on the threshold raises questions about the generality of a gating effect of NA in sensory neocortex.

Key words NoradrenalineNeuromodulatorIontophoresisIntensity functionThresholdRat

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Yves Manunta
    • 1
  • J.-M. Edeline
    • 1
  1. 1.Laboratoire de Neurobiologie de l’Apprentissage et de la Mémoire, URA 1491, Bat. 446, Université Paris-Sud, F-91405 Orsay Cedex, France Fax: +33-01-69-15-77-26FR