cGMP dissociates from CNG channels

Stable Identifier
Reaction [dissociation]
Homo sapiens
Decreased cGMP closes cation channels
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As cGMP is hydrolysed during the activation phase of phototransduction, its intracellular concentration decreases leading to the closure of CNG channel (the closed status is designated as CNG channel) (Dhallan et al. 1992, Chen et al. 1993). Channel closure reduces the inward flux of sodium and calcium (also known as the 'dark current') resulting in cell hyperpolarisation. Cooperative binding of cGMP to the CNG channel confers additional amplification to the phototransduction cascade (Pugh & Lamb 1993, Yau & Baylor 1989).

Literature References
PubMed ID Title Journal Year
8382952 Amplification and kinetics of the activation steps in phototransduction

Pugh, EN, Lamb, TD

Biochim. Biophys. Acta 1993
2467600 Cyclic GMP-activated conductance of retinal photoreceptor cells

Yau, KW, Baylor, DA

Annu. Rev. Neurosci. 1989
1379636 Human rod photoreceptor cGMP-gated channel: amino acid sequence, gene structure, and functional expression.

Reed, RR, Yau, KW, Nathans, J, Macke, JP, Dhallan, RS, Shows, TB

J Neurosci 1992
7682292 A new subunit of the cyclic nucleotide-gated cation channel in retinal rods

Peng, YW, Reed, RR, Yau, KW, Dhallan, RS, Ahamed, B, Chen, TY

Nature 1993
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