Cell water and ionic content were measured in aortic smooth muscle from rats and ground squirrels during 48 h of incubation in oxygenated Krebs solution held at low temperatures. Cells from the ground squirrel, a hibernator, maintained sodium and potassium contents near normal levels during incubation at 7°C. In sharp contrast, cells from the rat lost potassium and gained sodium with half times of 14 and 11 h, respectively. The [K] in cell water for the rat decreased 138 mM while [Na] in cell water increased about 148 mM. Cells from the hibernator tended to lose 10 mM K and gain 13 mM Na. Vascular smooth muscle of both the rat and squirrel was able to maintain K content at 17°C. Tissue content of the divalent cations Ca and Mg did not change in vessels from either animal. The present findings suggest that aortic smooth muscle cells from a hibernator have adapted in such a way as to maintain ionic gradients upon prolonged exposure to low temperatures.
ASJC Scopus subject areas
- Cell Biology