Study of experimental hypoparathyroidism in rats. III. Fluidity changes in brain synaptolemma

The changes of brain synaptolemma fluidity in experimental parathyroidectomized (PTX) rats were studied by using fluorescence polarization and differential scanning calorimetry (DSC) techniques. The results showed that microviscosity (eta) of the rat brain synaptolemma in the cerebral cortex, hippocampus, midbrain and striatum were decreased after a 2-month period of continuous hypocalcemia, and in the hippocampus and cerebral cortex it was decreased significantly as compared with control. These results suggest that the fluidity of the synaptolemma in the brains of hypocalcemic rats is increased. In addition, hypocalcemia also lowered the Tc of hippocampus synaptolemma lipid, which indicates that both fluidity and permeability had increased in these rats.