An unusual cGMP pathway underlying depolarizing light response of the vertebrate parietal-eye photoreceptor.
Nat Neurosci
; 1(5): 359-65, 1998 Sep.
Article
em En
| MEDLINE
| ID: mdl-10196524
ABSTRACT
All cellular signaling pathways currently known to elevate cGMP involve the activation of a guanylyl cyclase to synthesize cGMP. Here we describe an exception to this rule. In the vertebrate parietal eye, the photoreceptors depolarize to light under dark-adapted conditions, unlike rods and cones but like most invertebrate photoreceptors. We report that the signaling pathway for this response involves a rise in intracellular cGMP resulting from an inhibition of the phosphodiesterase that hydrolyzes cGMP. Furthermore, this phosphodiesterase is driven by an active G protein in darkness. These results indicate an antagonistic control of the phosphodiesterase by two G proteins, analogous to the Gs/Gi control of adenylyl cyclase. Our findings demonstrate an unusual phototransduction mechanism and at the same time indicate that signaling involving cyclic nucleotides is more elaborate than previously known.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Células Fotorreceptoras
/
GMP Cíclico
/
Luz
/
Lagartos
/
Fenômenos Fisiológicos Oculares
Limite:
Animals
Idioma:
En
Revista:
Nat Neurosci
Assunto da revista:
NEUROLOGIA
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Estados Unidos