Development of the L-type CaV / BK Complex Simulator (II): estimation of the distance between the channels

Abstract

The presence, in the cell membrane, of high-conductance K⁺ channels and voltage-gated Ca²⁺ channels (CaV) forming complexes has been reported. These complexes have important functions in excitable cells. The [Ca²⁺]_i at the mouth of the CaV channel decreases with distance and with the concentration of chelators. For the BK channel to be activated with internal Ca², a concentration of the order of M is necessary and this implies a closeness between the BK-CaV channels. A simulator of the decay of Ca²⁺ in the presence of BAPTA to estimate the distance between the channels was developed. The mathematical models were implemented in Visual Basic® 6.0 and were solved numerically. The results indicate the coexistence of L-type CaV channel and BK grouped in nanodomains with a distance between channels of ~30 nm.