The Involvement of Gs in Regulation of the L-Type Voltage-Gated Ca2+ Channel

Our interest in calcium channels was prompted by the results of studies published by Hescheler and collaborators at the beginning of 1987, in which these authors showed in whole cell recordings that the inhibitory regulation of the voltage gate calcium channels in NG108-15 cells in response to opioids is reconstituted after pertussis toxin (PTX) treatment with Go as well as Gi [1]. We attempted to obtain similar results by adding activated PTX-sensitive G proteins (Go or Gi) to inside-out membrane patches of cardiac ventricle cells, but we were faced with the fact that single calcium channel currents in inside-out membrane patches are extremely unstable, inactivating within 15–30s from the time of patch excision. By studying ways to stabilize calcium channel function in inside-out membrane patches we noted that these channels could be stabilized by activating what appeared to be Gs. The following is an account of some of these experiments and the research that followed.