Investigation of K⁺ channel expression in human peripheral lymphocytes of healthy donors by means of flow cytometry

Abstract

Evaluation of different types of K⁺ channel expression was performed in resting and PHA (phytohemagglutinine)-activated human peripheral lymphocytes (HPL) of healthy donors by means of flow cytometry. In resting peripheral lymphocytes, the application of kaliotoxin (a selective blocker for voltage-dependent K+ (K(V)) channels), K(V) resulted in pronounced depolarization of lymphocyte membrane potential, with further promotion in the presence of thapsigargin (compound discharging Ca_i from endoplasmic reticulum). In activated HPL, the expression of various types of K⁺ channels was estimated utilizing cell-cycle analysis data. In contrast to the resting cells, kaliotoxin-induced depolarization of membrane potential in PHA-activated lymphocytes of the G₀/G₁ phase was not enhanced by thapsigargin and in PHA-activated lymphocytes of the S and G2/M phases we were able to observe repolarization of membrane potential after kaliotoxin-induced depolarization of membrane potential. Substitution of kaliotoxin for charybdotoxin (a non-selective drug blocking both K(V) and K(Ca) channels) abrogated the above effects in PHA-activated lymphocytes. Thus, K(V) channels are active in both resting and activated HPLs and K(Ca) channel expression occurs with cell-cycle progress on PHA-induced activation of peripheral lymphocytes.