地松鼠红细胞中主动钠钾转运和被动通透性的温度适应性
Temperature adaptation of active sodium-potassium transport and of passive permeability in erythrocytes of ground squirrels.
作者信息
Kimzey S L, Willis J S
出版信息
J Gen Physiol. 1971 Dec;58(6):634-49. doi: 10.1085/jgp.58.6.634.
Unidirectional active and passive fluxes of (42)K and (24)Na were measured in red blood cells of ground squirrels (hibernators) and guinea pigs (nonhibernators). As temperature is lowered, "active" (ouabain-sensitive) K influx and Na efflux were more greatly diminished in guinea pig cells than in those of ground squirrels. The fraction of total K influx which is ouabain sensitive in red blood cells of ground squirrels was virtually constant at all temperatures, whereas it decreased abruptly in guinea pig cells as temperature was lowered. All the passive fluxes (i.e., Na influx, K efflux, and ouabain-insensitive K influx and Na efflux) decreased logarithmically with decrease in temperature in both species, but in ground squirrels the temperature dependence (Q(10) 2.5-3.0) was greater than in guinea pig (Q(10) 1.6-1.9). Thus, red blood cells of ground squirrel are able to resist loss of K and gain of Na at low temperature both because of relatively greater Na-K transport (than in cells of nonhibernators) and because of reduced passive leakage of ions.
在地松鼠（冬眠动物）和豚鼠（非冬眠动物）的红细胞中测量了(^{42}K)和(^{24}Na)的单向主动和被动通量。随着温度降低，豚鼠细胞中“主动”（哇巴因敏感）的钾离子内流和钠离子外流比地松鼠细胞中的减少得更多。在地松鼠红细胞中，哇巴因敏感的钾离子总内流比例在所有温度下实际上都保持恒定，而在豚鼠细胞中，随着温度降低，该比例会突然下降。在这两个物种中，所有被动通量（即钠离子内流、钾离子外流以及哇巴因不敏感的钾离子内流和钠离子外流）都随着温度降低呈对数下降，但地松鼠的温度依赖性（(Q_{10})为(2.5 - 3.0)）大于豚鼠（(Q_{10})为(1.6 - 1.9)）。因此，地松鼠的红细胞能够在低温下抵抗钾离子的流失和钠离子的增加，这既是因为相对更大的钠钾转运（比非冬眠动物的细胞），也是因为离子的被动泄漏减少。
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