L-dopa induces Ca(2+)-dependent and tetrodotoxin-sensitive release of endogenous glutamate from rat striatal slices.
L-DOPA (10-1000 microM) concentration-dependently released glutamate (Glu) from superfused rat striatal slices. D-DOPA and dopamine (300 microM) produced no effects. The L-DOPA-induced release of Glu was not affected by 3-hydroxybenzylhydrazine (20 microM), an L-aromatic amino acid decarboxylase inhibitor. L-DOPA methyl ester (200 microM), a selective L-DOPA antagonist, antagonized the effect of L-DOPA in a competitive manner. Ca2+ deprivation and tetrodotoxin decreased L-DOPA (300 microM)-induced release of Glu. These findings indicate that L-DOPA induces a transmitter-like release of Glu via activation of a recognition site for itself.
Goshima
Y
Y
Department of Pharmacology, Yokohama City University School of Medicine, Japan.
Ohno
K
K
Nakamura
S
S
Miyamae
T
T
Misu
Y
Y
Akaike
A
A
D000818:Animals; D002118:Calcium / Q000502:physiology*; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013779:Tetrodotoxin / Q000494:pharmacology*
D005971:Glutamates; D018698:Glutamic Acid; D013779:Tetrodotoxin; D007980:Levodopa; D002118:Calcium