Reverse microdialysis of a dopamine D2 receptor antagonist alters extracellular adenosine levels in the rat nucleus accumbens.
Recent evidence suggests that modulation of dopaminergic transmission alters striatal levels of extracellular adenosine. The present study used reverse microdialysis of the selective dopamine D(2) receptor antagonist raclopride to investigate whether a blockade of dopamine D(2) receptors modifies extracellular adenosine concentrations in the nucleus accumbens. Results reveal that perfusion of raclopride produced an increase of dialysate adenosine which was significant with a high (10 mM) and intermediate (1 mM) drug concentration, but not with lower drug concentrations (10 and 100 microM). Thus, the present study demonstrates that a selective blockade of dopamine D(2) receptors in the nucleus accumbens produced a pronounced increase of extracellular adenosine. The cellular mechanisms underlying this effect are yet unknown. It is suggested that the increase of extracellular adenosine might be related to a homeostatic modulatory mechanism proposed to be a key function of adenosine in response to neuronal metabolic challenges.
Nagel
J
J
Department of Animal Physiology, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, Stuttgart D-70550, Germany.
Hauber
W
W
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D018492:Dopamine Antagonists / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D005470:Fluorometry; D008297:Male; D017551:Microdialysis; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013238:Stereotaxic Techniques
D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D020891:Raclopride; D000241:Adenosine