INVESTIGADORES
FAILLACE Maria paula
artículos
Título:
GABA effect on melatonin content in golden hamster retina.
Autor/es:
JALIFFA CAROLINA; FAILLACE MARIA PAULA; FIRPO LACOSTE F; KELLER SARMIENTO MI; ROSENSTEIN RUTH
Revista:
JOURNAL OF NEUROCHEMISTRY
Editorial:
Wiley InterScience Journals
Referencias:
Año: 1999 vol. 72 p. 1999 - 2005
ISSN:
0022-3042
Resumen:
The effect of GABA on melatonin content in vitro was studied in the
golden hamster retina. GABA significantly increased melatonin levels in
a dose-dependent manner, its effect being reversed by a GABA(A)
receptor antagonist, bicuculline, but not by saclofen, a GABA(B)
antagonist. Moreover, an equimolar concentration of muscimol, a GABA(A)
receptor agonist, significantly increased retinal melatonin content,
whereas baclofen, a GABA(B) receptor agonist, was ineffective. The
darkness-induced increase in melatonin content in vitro was inhibited
by bicuculline, whereas saclofen was ineffective. Retinal GABA turnover
rate was significantly higher at midnight than at midday. GABA
significantly decreased cyclic AMP and increased cyclic GMP
accumulation in the golden hamster retina. The effect of GABA on both
nucleotide levels was reversed by bicuculline, but baclofen had no
effect. Cyclic GMP analogues (i.e., 8-bromoguanosine 3',5'-cyclic
monophosphate and 2'-O-dibutyrylguanosine 3',5'-cyclic monophosphate)
significantly increased retinal melatonin content in vitro. Taken
together, these results support the hypothesis that GABA may be
important for the "dark message" in the hamster retina.