Light-sensitive Channels, Pumps, and Carriers

In planning our discussion, a series of broad questions relating to the structural and functional properties of light-sensitive channels were formulated as follows: 1) What do the characteristics of the macroscopic light-dependent current tell us about the molecular architecture of the channel? 2) What are the properties of the Na2+/Ca2+ exchange carrier and how do these influence both the operation of the transduction mechanism and out interpretation of results from experimental studies of the light-sensitive channel? 3) What do microscopic measurements (e.g., noise analysis, single-channel recordings) tell us about the light-sensitive channel and its gating? 4) How does the light-sensitive channel respond to possible transmitter substances? 5) What does the electrical fine-structure of the single-photon event (quantum bump) tell us about the mechanism of channel opening and closure?