Effect of different illumination conditions and ionic environment on the guanylate cyclase activity in retina, optic nerve and optic chiasm of the rat.
J Physiol Paris
; 91(2): 91-5, 1997 Apr.
Article
em En
| MEDLINE
| ID: mdl-9326737
ABSTRACT
Guanylate cyclase is sensitive to changes of light and dark periods in incubated extracts obtained from soluble fractions of the retina, optic nerve and optic chiasm. The changes in guanylate cyclase activity found, about 100-fold between dark and light periods in those tissues, indicate a key role for this enzyme. The results showed that light inhibits strongly the retinal guanylate cyclase activity, while it increases the activity of this enzyme in the optic nerve. A generalized photo-inhibited response of guanylate cyclase was observed in all studied tissues in animals adapted to the dark. This suggests that light could act as a double stimulus gating the central circuit which promotes the hydrolysis of cGMP via cGMP phosphodiesterase-rhodopsin-transducin cascade, and by direct inhibition of the retinal guanylate cyclase activity. Finally, different responses have been observed in the guanylate cyclase activity in relation with the ion exposure depending on the studied tissue. In summary, all indicate an important role for the soluble guanylate cyclase activity in retina, and other tissues involved in the visual process such as optic nerve and optic chiasm, which have not been examined until now.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Quiasma Óptico
/
Nervo Óptico
/
Retina
/
Iluminação
/
Guanilato Ciclase
Limite:
Animals
Idioma:
En
Revista:
J Physiol Paris
Assunto da revista:
FISIOLOGIA
Ano de publicação:
1997
Tipo de documento:
Article