A study of photodynamic effect of new photosensitizers on a single nerve cell

We studied reactions of isolated crayfish mechanoreceptor neurons to photod ynamic effects of various photosensitizers: methylene blue, chlorins e(6) a nd p(6), sulfated allumophthalocyanin Photosens, Janus green B, protoporphy rin IX, and two derivatives of hematoporphyrin IX, Photoheme and Photosan-3 . The neurons were irradiated by a helium-neon laser (632.8 nm, 0.3 Wt/cm(3 )) after 30-min photosensitization. They proved to be very sensitive to the photodynamic effect: When the cells stained by photosensitizers at nanomol ar concentrations were irradiated, their firing activity underwent irrevers ible changes and they died. The dynamics of the firing activity of the neur ons depended on the photosensitizer type and concentration. Photosens, Phot oheme and chlorin p(6) proved to be the most efficient.