Channelrhodopsin-2 is a leaky proton pump.

Since its discovery, the light-gated cation channel Channelrhodopsin-2 (ChR2) has proven to be a long-sought tool for the noninvasive, light-activated control of neural cells in culture and in living animals. Although ChR2 is widely used in neurobiological applications, little is known about its molecular mechanism. In this work, the unitary conductance of ChR2 was determined for different cations, for example 40 fS at 200 mM NaCl and -60 mV, using noise analysis.

Time resolved kinetics of the guinea pig Na-Ca exchanger (NCX1) expressed in Xenopus oocytes: voltage and Ca(2+) dependence of pre-steady-state current investigated by photolytic Ca (2+)concentration jumps.

Kinetic properties of the Na-Ca exchanger (guinea pig NCX1) expressed in Xenopus oocytes were investigated by patch clamp techniques and photolytic Ca(2+) concentration jumps. Current measured in oocyte membranes expressing NCX1 is almost indistinguishable from current measured in patches derived from cardiac myocytes. In the Ca-Ca exchange mode, a transient inward current is observed, whereas in the Na-Ca exchange mode, current either rises to a plateau, or at higher Ca(2+) concentration jumps, an initial transient is followed by a plateau.