The auxiliary Ca(v)beta subunit is essential for functional expression of high-voltage activated Ca2+ channels. Here, we describe a lure sequence designed to sequester the Ca(v)beta subunits in transfected bovine chromaffin cells. This sequence is composed of the extracellular and transmembrane domains of the alpha chain of the human CD8, the I-II loop of Ca(v)2.1 subunit, and EGFP. We showed that expressing the CD8-I-II-EGFP sequence in chromaffin cells led to a >50% decrease in overall Ca2+ current density. Although this decrease involved all the Ca2+ channel types (L, N, P/Q, R), the proportion of each type supporting the remaining current was altered. A similar effect was observed after transfection when measuring the functional role of Ca2+ channels in catecholamine release by chromaffin cells: global decrease of release and change of balance between the different channel types supporting it. Possible explanations for this apparent discrepancy are further discussed. (C) 2003 Elsevier Inc. All rights reserved.