Ciliary photoreceptors of the scallop (Pecten irradians) respond to light with a hyperpolarization. Patch-clamp studies have shown that intracellular dialysis of cGMP opens light-activated K+ channels. In order to identify the light-activated channel, I have molecularly identified different ion channels that harbor a cyclic-nucleotide binding domain (HCN, CNG and ERG channels), expressing in the ciliary photoreceptors of Pecten. I aim to study the physiological role played by these ion channels in native ciliary photoreceptors of the scallop by using the patch-clamp technique. This approach will help to deeper understand the different photo-transduction pathways present through the ciliary photoreceptor lineage.