Influence of glycogen content, temperature, and Euro Collins solution on membrane potential and sodium activity of superfused porcine liver slices.
The influence of glycogen content, temperature, and Euro Collins (EC) solution on membrane potential (Vm) and intracellular sodium activity (aNai) were measured in cells of superfused porcine liver slices by means of double-barrelled ion-sensitive microelectrodes. Vm was -26.1mV in fasted pigs and -20.6mV after glucose feeding, when measured in HEPES-buffered solution (P less than 0.0001). aNai was not measurably affected by glucose feeding. During superfusion with Tyrode solution, lowering the temperature from 35.5 degrees C to 15.5 degrees C led to a fast Vm decrease of roughly 2mV followed by an increase of 1-3mV. At the same time, aNai increased from 12.8 to 18.2mM within 10 min. Superfusion with EC solution for 10 min caused comparable changes in fed and fasted pigs. Vm depolarized at either temperature by about 16mV. At 35.5 degrees C the initial aNai of 17.5mM was roughly halved, whereas at 15.5 degrees C it decreased from 21.0 to 14.3mM. The results suggest that the nutritional state markedly affects the electric properties of liver. However, the effect on membrane potential of high-potassium organ-protective solutions seems to be distinctly more pronounced. Moreover, cellular Na+ activity decreases in consequence of an extracellular Na+ reduction with protective solutions, which might be balanced to some extent by a simultaneous temperature decrease.
Zentrum Physiologie und Pathophysiologie, Universität Göttingen, Federal Republic of Germany.
M
M
Fleckenstein
G
G
Kehrer
M M
MM
Gebhard
H J
HJ
Bretschneider
D000818:Animals; D005215:Fasting; D005260:Female; D005947:Glucose / Q000008:administration & dosage; D006982:Hypertonic Solutions; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008112:Liver Glycogen / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials; D009926:Organ Preservation; D010477:Perfusion; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013552:Swine; D013696:Temperature
C037096:Euro-Collins' solution; D006982:Hypertonic Solutions; D008112:Liver Glycogen; D012964:Sodium; D005947:Glucose