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In vivo regulation of dopamine and noradrenaline release by alpha2A‐adrenoceptors in the mouse nucleus accumbens
Author(s) -
Ihalainen Jouni A.,
Tanila Heikki
Publication year - 2004
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02691.x
Subject(s) - microdialysis , nucleus accumbens , agonist , dopamine , endocrinology , medicine , chemistry , antagonist , in vivo , neurotransmitter , catecholamine , pharmacology , biology , receptor , central nervous system , microbiology and biotechnology
The present study investigated the role of alpha2A‐adrenoceptor (α 2A ‐AR) subtype in the regulation of noradrenaline (NA) and dopamine (DA) release in the nucleus accumbens (NAc). The effect of locally infused and systemically injected α 2 ‐AR agonist, dexmedetomidine (DMT), and α 2 ‐AR antagonist, atipamezole, on NA and DA release was investigated in α 2A ‐AR knockout and control mice by using in vivo microdialysis. In addition, we compared the drug effects on DA and NA release in the NAc to their effect on locomotor activity. Baseline NA and DA concentrations did not differ between genotypes. Local infusion of DMT decreased, in a concentration‐dependent manner, NA, but not DA, levels in the control mice. However, systemic injection of DMT decreased both NA and DA levels in the control mice. In both cases DMT had no effects on transmitter release in α 2A ‐AR knockout mice. Our results suggest that α 2 ‐ARs regulate the release of NA, but not DA, at the terminal level in the NAc. However, α 2 ‐ARs regulate DA release in the NAc indirectly by their effect on DA neurones in the ventral tegmental area via an unknown mechanism. In both cases the regulation is mediated by α 2A ‐adrenoceptor subtype. Also the modulation of locomotor activity by α 2 ‐AR agonist and antagonist seems to be mediated via α 2A ‐adrenoceptors.