Maxi-K channels in plasma cells.

Whole-cells, excised outside-in and outside-out membrane patches were employed to study the electrophysiological properties of plasma cells isolated from the Harderian (lacrimal) gland of chicken. The study revealed that the whole-cell currents are dominated by outward rectifying currents which display slow inactivation times of the order of seconds. Records from excised outside-in and outside-out patches consistently revealed one channel type, a maxi-K channel. These maxi-K channels were shown to be both voltage and calcium sensitive. The single channel conductance of the maxi-K channel, with KCl solutions on both sides of the patch, ranged from 200-265 pS (n = 26). Both whole-cell currents and single channel activity (outside-out) were reduced by the introduction of 10 mM TEA in the bath. The ease with which a large number of plasma cells can be isolated free of undifferentiated B-lymphocytes makes this preparation ideal for studying the relationship between the electrophysiological properties and immunoglobulin secretion in plasma cells.