Local muscimol disinhibits mesolimbic dopaminergic activity as examined by brain microdialysis and Fos immunohistochemistry.
Infusion of muscimol (5 X 10[-5] M, 60 min) into the nucleus accumbens (NAC) through a dialysis membrane caused a significant increase in extracellular dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC). Fos-like immunoreactivity induced by intra-NAC infusion of muscimol was seen ipsilaterally in many accumbofugal target areas, but no Fos-positive neurons were seen in the vicinity of the dialysis membrane in the NAC. Sequential staining of Fos and tyrosine hydroxylase (TH) immunoreactivities revealed that a portion of A10 dopaminergic neurons were double-labelled. These results suggest that muscimol in the NAC disinhibits mesolimbic DA neuronal activity possibly through activity of the accumbofugal GABA neuron system.
Yoshida
M
M
Department of Pharmacology, Kurume University School of Medicine, Japan.
Yokoo
H
H
Nakahara
K
K
Tomita
M
M
Hamada
N
N
Ishikawa
M
M
Hatakeyama
J
J
Tanaka
M
M
Nagatsu
I
I
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D017551:Microdialysis; D009118:Muscimol / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar
D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D015102:3,4-Dihydroxyphenylacetic Acid; D009118:Muscimol; D004298:Dopamine