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Dopamine‐somatostatin interactions in the rat striatum: An in vivo microdialysis study
Author(s) -
Thermos Kyriaki,
Radke James,
Kastellakis Andreas,
Anagnostakis Yannis,
Spyraki Christina
Publication year - 1996
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(199603)22:3<209::aid-syn2>3.0.co;2-g
Subject(s) - somatostatin , dopamine , dopaminergic , microdialysis , striatum , sulpiride , endocrinology , medicine , chemistry , neurotransmitter , apomorphine , agonist , pharmacology , biology , central nervous system , receptor
Dopamine‐somatostatin interactions were investigated in the rat striatum using in vivomicrodialysis. Somatostatin‐14 and somatostatin‐28 (10 −4 ,10 −5 , 10 −6 M) were infused, and the levels ofdopamine and its metabolites DOPAC and HVA were assessed using high pressure liquidchromatography with electrochemical detection. Somatostatin‐14 was more effective thansomatostatin‐28 in producing a dose‐dependent increase in dopamine levels with no significantalterations in the levels of the metabolites. To assess the effect of dopamine on somatostatinergicneurons, dopaminergic agents were administered and somatostatin levels measured using aradioimmunoassay. The nonselective agonist apomorphine was administered subcutaneously(0.00, 0.05, 0.10, 0.50, 1.00 mg/kg) or directly infused (10 −4 ,10 −5 M) in the striatum. The selective D1 and D2 dopamine antagonistsSCH23390 and sulpiride, respectively, were also infused at concentrations of10 −4 and 10 −5 M. None of these agents elicitedany significant changes in the somatostatin release in the striatum, while altering dopaminerelease. This study provides for the first time evidence regarding dopamine‐somatostatininteractions in the awake and freely moving animal. The results confirm that somatostatinmodulates the function of dopaminergic neurons in the striatum and provide new evidence thatsomatostatin‐14 may differentially regulate dopamine release. Furthermore, our findings suggestthat dopamine does not play a major role in the regulation of somatostatin neurons. © 1996Wiley‐Liss, Inc.