Combined microdialysis and Fos immunohistochemistry for the estimation of dopamine neurotransmission in the rat caudate-putamen.
Extracellular dopamine (DA) concentrations estimated by transcerebral dialysis and D1-dependent c-fos expression, as demonstrated by Fos immunohistochemistry, were studied after blockade of DA reuptake by GBR-12909. Rats implanted with dialysis probes in the dorsal caudate-putamen did not show any Fos-positive neuronal labeling in the implanted area or in the rest of the caudate-putamen. Administration of GBR-12909 dose-dependently increased DA output in dialysates and resulted in the appearance in the caudate-putamen of Fos-positive neurons whose density was related to the dose of GBR-12909 and to the increase in extracellular concentrations of DA. The D1 antagonist SCH-23390 blocked GBR-12909-induced activation of Fos while potentiating the stimulation of DA output. The results show that following blockade of DA reuptake by GBR-12909, the induction of Fos is related to stimulation of D1 receptors by extracellular DA. Combination of brain dialysis with Fos immunohistochemistry might provide a method for estimating the functional significance of extracellular DA as measured by brain microdialysis.
Morelli
M
M
Department of Toxicology, University of Cagliari, Italy.
Carboni
E
E
Cozzolino
A
A
Tanda
G L
GL
Pinna
A
A
Di Chiara
G
G
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001552:Benzazepines / Q000494:pharmacology; D002421:Caudate Nucleus / Q000378:metabolism / Q000502:physiology*; D003956:Dialysis / Q000379:methods; D004298:Dopamine / Q000502:physiology*; D018492:Dopamine Antagonists; D007150:Immunohistochemistry; D008297:Male; D014179:Neurotransmitter Uptake Inhibitors / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011699:Putamen / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission / Q000502:physiology*
D001552:Benzazepines; D018492:Dopamine Antagonists; D014179:Neurotransmitter Uptake Inhibitors; D010879:Piperazines; D016760:Proto-Oncogene Proteins c-fos; C043425:vanoxerine; D004298:Dopamine