Temperature dependence of the sodium pump is altered in the cerebral cortex of CCK2 receptor-deficient mice.

Previously we have shown that the temperature dependence of the sodium pump (Na(+),K(+)-ATPase) is altered under different neuropathological conditions. In this study we compared temperature dependence of the Na(+),K(+)-ATPase in the fronto-parietal cortex of CCK(2) receptor-deficient (homo- and heterozygous) and normal (wild-type) mice. The Arrhenius plot for Na(+),K(+)-ATPase from wild-type brain is non-linear with a breakpoint at 20.3 +/- 0.4 degrees C. In case of the brain cell membrane of CCK(2) receptor-deficient mice (homo- and heterozygous) the breakpoint on Arrhenius plot was detected at 26.0 +/- 1.1 degrees C and 25.4 +/- 0.4 degrees C, respectively. The shift of the breakpoint on the Arrhenius plot established in CCK(2) receptor-deficiency as well as in case of some other pathological conditions confirms that such kind of alteration in the Na(+),K(+)-ATPase temperature dependence is likely related to the homeostatic adjustment of altered function of the sodium pump.