Lysophosphatidylserine increases membrane potentials in rat C6 glioma cells

Abstract

Previously, we reported on the distinct effects of bioactive lysophospholipids, including lysophosphatidic acid (LPA), lysophosphatidylcholine (LPC), and sphingosylphosphorylcholine (SPC), on membrane potentials in rat C6 glioma cells. In the present report we have tested lysophosphatidylserine (LPS), another bioactive lysophospholipid, on membrane potentials in the same cell line. Membrane potentials were estimated by measuring the fluorescence changes of DiBAC-loaded glioma cells. LPS largely increased membrane potentials in a concentration-dependent manner. The LPS-induced membrane potential increases were not affected by treatment with pertussis toxin, implying no involvement of Gi/o proteins. In contrast to other lysophospholipids, the LPS-induced membrane potential increase was not diminished by a Na(+)-free media but was enhanced by suramin. Furthermore, this change was blunted by EIPA, an inhibitor of Na(+)/H(+) exchanger, but not by SITS, a specific inhibitor of bicarbonate transporter. Our observations suggest that LPS acts on membrane potentials in a unique manner in the C6 glioma cells, although the precise action mechanism requires additional investigation.

Wuweizisu C fromSchisandra chinensisdecreases membrane potential in C6 glioma cells1

“…In this study, the effects of wuweizisu C, gomisin A, gomisin N, and schisandrin, which are dibenzooctadiene lignans of Schisandra fruits, on the membrane potential were investigated in C6 glioma cells. We previously observed an increase of the membrane potential with sarcotride A and bio-active lysophospholipids, such as lysophosphatidic acid and lysophosphatidylserine in C6 glioma cells [29,33,34] . In the present study, we showed decreases of the membrane potential by wuweizisu C, gomisin N, and gomisin A.…”

“…After 30 min of EIPA treatment, it was impossible to say whether NHE was a component of the wuweizisu C-induced decrease in the membrane potential because the resting membrane potential was decreased by the EIPA treatment. However, EIPA-sensitive NHE was definitely a regulator of the membrane potential in C6 cells [33] .…”

“…We previously observed an increase of the membrane potential with sarcotride A and bio-active lysophospholipids, such as lysophosphatidic acid and lysophosphatidylserine in C6 glioma cells [29,33,34] . In the present study, we showed decreases of the membrane potential by wuweizisu C, gomisin N, and gomisin A.…”