Zunaira saleh6 days ago

Phototransduction

Phototransduction in the outer segment of the photoreceptor (rod or cone) membrane. When light hits the photoreceptor (e.g., a rod cell), the light-absorbing retinal portion of rhodopsin is activated. This activation stimulates transducin, a G protein, which then activates cGMP phosphodiesterase. This enzyme catalyzes the degradation of cGMP into 5′-GMP. The reduction in cGMP then causes closure of the sodium channels, which, in turn, causes hyperpolarization of the photoreceptor.