The ion channels, transporters and metabotropic receptors that underlie
neuronal activity can be seen as molecular machines that are amenable to
functional manipulation. One of the most rewarding functions to add is
sensitivity toward light. Our group has succeeded in photosensitizing
several ion channels, such as glutamate receptors and voltage-gated
potassium channels using a combination of synthetic chemistry and
protein engineering. In addition, we have developed .reversibly caged.
versions of glutamate and other neurotransmitters. I will discuss the
principles that underlie the design of artificial photoreceptors and
photochromic neurotransmitters. In particular, I will address our
systematic studies on their dynamic properties, which are of crucial
importance for their biological applications. The use of our hybrid
photoreceptors in cultured neurons, brain slices, and intact animals
(e.g. zebrafish, leeches and mice) will be shown and the role of these
systems in the elucidation of neural circuitry and the restoration of
vision will be discussed.