G. Panyi et al., PERIPHERAL-BLOOD LYMPHOCYTES DISPLAY REDUCED K+ CHANNEL ACTIVITY IN AGED HUMANS, Biochemical and biophysical research communications, 199(2), 1994, pp. 519-524
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 dependen
ce of the K+ conductance were similar in both lymphocyte populations.
The midpoint of steady-state inactivation was -53.3 +/- 2.3 mV for lym
phocyte 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 d
ecreased and shifted to depolarized potentials by approx. 12.5 mV for
lymphocytes of elderly donors. It is suggested that the observed diffe
rences in the K+ current parameters may be at least partly responsible
for the impaired responsiveness of elderly lymphocytes to proliferati
ve stimuli. (C) 1994 Academic Press, Inc.