Peripheral blood lymphocytes display reduced K+ channel activity in aged humans.
Steady-state parameters of whole-cell K+ current have been determined in human peripheral blood lymphocytes of young (20-50 y.) and elderly (> 90 y.) volunteers by patch-clamp. The magnitude and voltage dependence of the K+ conductance were similar in both lymphocyte populations. The midpoint of steady-state inactivation was -53.3 +/- 2.3 mV for lymphocyte population of young individuals and -65.0 +/- 3.0 mV for that of elderly, showing a significant shift to hyperpolarized potentials. The peak of the steady-state open probability of the K+ channels was decreased and shifted to depolarized potentials by approx. 12.5 mV for lymphocytes of elderly donors. It is suggested that the observed differences in the K+ current parameters may be at least partly responsible for the impaired responsiveness of elderly lymphocytes to proliferative stimuli.
Panyi
G
G
Department of Biophysics, University Medical School of Debrecen, Hungary.
Berecki
G
G
Gáspár
R
R
Seres
I
I
Fülöp
T
T
Damjanovich
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D002478:Cells, Cultured; D004553:Electric Conductivity; D006801:Humans; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D008214:Lymphocytes / Q000502:physiology*; D008564:Membrane Potentials; D008875:Middle Aged; D015221:Potassium Channels / Q000502:physiology*; D011336:Probability
D015221:Potassium Channels