Physiological release of striatal acetylcholine (in vivo): Effect of somatostatin on dopaminergic-cholinergic interaction

Angelina Rakovska, Daniel Javitt, Peter Raichev, Rosalind Ang, Andrea Balla, John Aspromonte, Sylvester Vizi

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The effects of somatostatin (SOM) on the release of acetylcholine (ACh) and dopamine (DA) from striatum of freely moving rats were studied by transversal microdialysis. Acetylcholine (ACh) and dopamine (DA) were detected by high performance liquid chromatography (HPLC) with electrochemical detection. Somatostatin (0.1, 0.5 and 1μM), administered locally through the microdialysis probe to the striatum, was able to release dose-dependently ACh from the cholinergic neurons of the striatum. The increase in the extracellular levels of ACh produced by 1μM SOM in the striatum reached a maximum of 200%. ACh-releasing effect of SOM was completely inhibited by tetrodotoxin indicating that neuronal firing is involved in its effect. Local infusion of sulpiride, 10μM, D2 receptor antagonist, potentiated (about 100%) the SOM (1μM)-induced release of ACh. SOM, 1μM, was more effective in enhancing the release of ACh in the striatum (two-fold increase) after degeneration of the nigrostriatal DA pathway with 6-hydroxydopamine (6-OHDA) (250μg/animal, i.c.v.). The D2 receptor agonists bromcriptine, 10μM, or apomorphine, 10μM, completely antagonize SOM-induced release. SOM, 1μM, enhanced the release of DA (about 400%). These findings indicate that SOM is capable of releasing both ACh and DA in the striatum, however, its effect on ACh release is partially masked unless the D2 receptor-mediated tonic inhibitory effect of released DA from the nigro-striatal pathway is attenuated.

Original languageEnglish
Pages (from-to)529-536
Number of pages8
JournalBrain Research Bulletin
Volume61
Issue number5
DOIs
Publication statusPublished - Sep 30 2003

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Keywords

  • Acetylcholine release
  • DA release
  • Microdialysis
  • Somatostatin
  • Striatum

ASJC Scopus subject areas

  • Neuroscience(all)

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