Green laser light (532 nm) activates a chloride current in the C1 neuron of Helix aspersa

Five hundred and thirty-two nanometers laser light evokes neuron-specific electrical responses in identified neurons of Helix ganglia. Such responses are intensity-dependent over the range 25–1500 mW, readily reversible and repeatable. Detailed experiments on the C1 neuron, which is inhibited by 532 nm light, showed that inhibition results from a selective increase in transmembrane Cl− ion conductance. Experiments with calcium-sensitive microelectrodes suggest that the response does not result from an increase in [Ca2+]i. The change in Cl− ion conductance probably occurs in the extensive plasmalemma infoldings of the proximal axon.