Light-driven calcium signals in mouse cone photoreceptors.
J Neurosci
; 32(20): 6981-94, 2012 May 16.
Article
em En
| MEDLINE
| ID: mdl-22593066
ABSTRACT
Calcium mediates various neuronal functions. The complexity of neuronal Ca²âº signaling is well exemplified by retinal cone photoreceptors, which, with their distinct compartmentalization, offer unique possibilities for studying the diversity of Ca²âº functions in a single cell. Measuring subcellular Ca²âº signals in cones under physiological conditions is not only fundamental for understanding cone function, it also bears important insights into pathophysiological processes governing retinal neurodegeneration. However, due to the proximity of light-sensitive outer segments to other cellular compartments, optical measurements of light-evoked Ca²âº responses in cones are challenging. We addressed this problem by generating a transgenic mouse (HR2.1TN-XL) in which both short- and middle-wavelength-sensitive cones selectively express the genetically encoded ratiometric Ca²âº biosensor TN-XL. We show that HR2.1TN-XL allows recording of light-evoked Ca²âº responses using two-photon imaging in individual cone photoreceptor terminals and to probe phototransduction and its diverse regulatory mechanisms with pharmacology at subcellular resolution. To further test this system, we asked whether the classical, nitric oxide (NO)-soluble guanylyl-cyclase (sGC)-cGMP pathway could modulate Ca²âº in cone terminals. Surprisingly, NO reduced Ca²âº resting levels in mouse cones, without evidence for direct sGC involvement. In conclusion, HR2.1TN-XL mice offer unprecedented opportunities to elucidate light-driven Ca²âº dynamics and their (dys)regulation in cone photoreceptors.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Cálcio
/
Células Fotorreceptoras Retinianas Cones
/
Troponina C
/
Transdução de Sinal Luminoso
/
Proteínas Luminescentes
Tipo de estudo:
Evaluation_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Neurosci
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Alemanha