Meeting Abstract

48.2  Sunday, Jan. 5 10:15  The response of octopus chromatophores to light is independent of the CNS and may be mediated by r-opsin phototransduction genes RAMIREZ, D*; OAKLEY, TH; Univ. of California, Santa Barbara ramirez@lifesci.ucsb.edu

Both eyed and eyeless animals depend on sensors in their skin to detect changes in light, a phenomenon known as dispersed photoreception. Currently, the molecular mechanisms of this light sense are known only in a few species. Most mollusks have both light-on and light-off behaviors that depend on dispersed light sensing, but descriptions of these behaviors are minimal in cephalopods. We have found that bright light causes muscle contractions and chromatophore expansion in isolated skin from Octopus bimaculoides. These light-on responses are similar to ones described in isolated siphons from Aplysia species, and chromatophore responses elicited by directed blue light in midwater cephalopods. We have previously found that r-opsin phototransduction genes are expressed in octopus skin, and also identified r-opsin-expressing peripheral sensory neurons in the skin. Taken together, these data suggest that the light-on chromatophore response of isolated O. bimaculoides skin may be mediated by r-opsin phototransduction genes expressed in sensory neurons in the skin.