Structural determinants of L-type channel activation in segment IIS6 revealed by a retinal disorder.

The mechanism of channel opening for voltage-gated calcium channels is poorly understood. The importance of a conserved isoleucine residue in the pore-lining segment IIS6 has recently been highlighted by functional analyses of a mutation (I745T) in the Ca(V)1.4 channel causing severe visual impairment (Hemara-Wahanui, A.

A CACNA1F mutation identified in an X-linked retinal disorder shifts the voltage dependence of Cav1.4 channel activation.

Light stimuli produce graded hyperpolarizations of the photoreceptor plasma membrane and an associated decrease in a voltagegated calcium channel conductance that mediates release of glutamate neurotransmitter. The Ca(v)1.4 channel is thought to be involved in this process.

Membrane properties of single muscle cells of the rhabdosphincter of the male urethra.

Background: The electrophysiological properties of myoblast cultures established from the human and porcine rhabdosphincter (RS) and porcine lower limb muscle (LLSKM) were studied to elucidate their potential for tissue engineering applications in the lower urinary tract.

Methods: Muscle biopsies were collected from the prostatic part of the RS, the RS of male pigs, and the porcine LLSKM. Ion channels were studied by means of the patch-clamp technique.