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Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 355, Issue 5, pp 576–581 | Cite as

Cholecystokinin-8S increases dynorphin B, aspartate and glutamate release in the fronto-parietal cortex of the rat via different receptor subtypes

  • Zhi-Bing You
  • Oleg Godukhin
  • Michel Goiny
  • Ingrid Nylander
  • Urban Ungerstedt
  • Lars Terenius
  • Tomas Hökfelt
  • M. Herrera-Marschitz
Original article

Abstract

The effect of sulphated cholecystokinin-8 (CCK-8S) on extracellular dynorphin B, aspartate, glutamate and GABA levels in the rat fronto-parietal cortex was investigated with in vivo microdialysis. The peptide was infused through the microdialysis probe trying to mimic local CCK-8S release. Basal levels of dynorphin B were around 20pM, aspartate 100nM, glutamate 600nM and GABA 30nM. CCK-8S (10μM) induced a ≈3-fold increase in extracellular dynorphin B, aspartate and glutamate levels, while GABA levels were only slightly increased. The effect of CCK-8S was restricted to the stimulated neocortex. Systemic pretreatment with the CCKB antagonist, L-365, 260, but not with the CCKA antagonist, L-364, 718, significantly antagonised the effect of CCK-8S on cortical dynorphin B and aspartate release. However, both CCKA and CCKB antagonists inhibited the increase in cortical glutamate levels. Thus, the present results indicate that cortical CCK release exerts a stimulatory modulation on cortical dynorphin B and aspartate release via the CCKB receptor subtype, and on glutamate release via both CCKA and CCKB receptor subtypes. Considering electrophysiological evidence that CCK increases neuronal firing rates in many brain regions, it may be suggested that CCK represents a stimulatory system modulating the function of the neocortex.

Key words Neocortex Cholecystokinin Dynorphin Amino acids Microdialysis Rat 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Zhi-Bing You
    • 1
  • Oleg Godukhin
    • 1
  • Michel Goiny
    • 1
  • Ingrid Nylander
    • 2
  • Urban Ungerstedt
    • 1
  • Lars Terenius
    • 2
  • Tomas Hökfelt
    • 3
  • M. Herrera-Marschitz
    • 1
  1. 1.Department of Physiology and Pharmacology, Karolinska Institute, S-17177 Stockholm, SwedenSE
  2. 2.Department of Clinical Neuroscience, Karolinska Institute, S-17177 Stockholm, SwedenSE
  3. 3.Department of Neuroscience, Karolinska Institute, S-17177 Stockholm, SwedenSE

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