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In vivo characterization of the angiotensin‐(1–7)‐induced dopamine and γ‐aminobutyric acid release in the striatum of the rat
Author(s) -
Stragier Bart,
Hristova Ilina,
Sarre Sophie,
Ebinger Guy,
Michotte Yvette
Publication year - 2005
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2005.04188.x
Subject(s) - microdialysis , dopamine , striatum , chemistry , glutamate receptor , aminobutyric acid , endocrinology , medicine , neurotransmitter , pharmacology , receptor , biology , biochemistry
The effect of angiotensin (Ang)‐1–7 on dopamine, γ‐aminobutyric acid (GABA) and glutamate release in the striatum of the rat was examined using in vivo microdialysis. Ang‐(1–7) was administered locally in the striatum through the microdialysis probe. At a concentration of 100 µ m , Ang‐(1–7) caused a significant increase in extracellular dopamine and GABA but had no effect on glutamate release. The Ang‐(1–7)‐induced dopamine release was blocked by EC33, an inhibitor of aminopeptidase A, an enzyme which converts Ang‐(1–7) into Ang‐(3–7), suggesting that this effect occurs after metabolism into Ang‐(3–7). Indeed, administration of Ang‐(3–7) (10–100 µ m ) into the striatum caused a more potent increase in the striatal dopamine release than Ang‐(1–7). Because Ang‐(3–7) is an inhibitor of insulin‐regulated aminopeptidase (IRAP) and because Ang IV, another IRAP inhibitor, also causes a concentration‐dependent increase in dopamine in the rat striatum, IRAP may be involved in this effect. In contrast, EC33 had no effect on the Ang‐(1–7)‐induced GABA increase but the GABA release was blocked by the putative AT 1‐7 receptor antagonist A779 (0.1 µ m ) and by the nitric oxide synthase inhibitor L‐NAME (1 m m ). These drugs could not block the effect of Ang‐(1–7) on the striatal dopamine release suggesting that only the observed effects on GABA release are mediated by the AT 1‐7 receptor and/or are associated with a release of nitric oxide.