Immunocytochemical evidence that vigabatrin in rats causes GABA accumulation in glial cells of the retina.
Vigabatrin (gamma-vinyl-GABA, GVG) is an irreversible inhibitor of GABA-aminotransferase (GABA-T) that is under clinical trial as an antiepileptic drug. Rats were injected (i.p.) with GVG and killed 18 h later. GVG administration reduced retinal GABA-T activity to undetectable levels and increased the GABA content 5-fold. Immunocytochemistry using a GABA antiserum clearly revealed the presence of GABA-IR in the glial Muller cells of retinas from GVG-treated rats but not from controls. This experiment indicates that the administration of drugs which inhibit GABA-T may cause the accumulation of GABA in retinal cells that do not normally possess enough endogenous GABA to be detected by immunocytochemistry.
Neal
M J
MJ
Department of Pharmacology, UMDS, St. Thomas's Hospital, London, U.K.
Cunningham
J R
JR
Shah
M A
MA
Yazulla
S
S
D000614:Aminocaproates / Q000494:pharmacology*; D000818:Animals; D007150:Immunohistochemistry; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020888:Vigabatrin; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000614:Aminocaproates; D005680:gamma-Aminobutyric Acid; D020888:Vigabatrin