An Na(+)- and HCO3(-)-independent mechanism of cytoplasmic pH (pHi) recovery was previously demonstrated in acid-loaded macrophages (Swallow, C. J., Grinstein, S., and Rotstein, O. D. (1988) J. Biol. Chem. 263, 19558-19563). Acid extrusion was found to be ATP-dependent and sensitive to N-ethylmaleimide and N,N'-dicyclohexylcarbodiimide, suggesting involvement of an H(+)-pumping ATPase. In this ...

Lateral mobility of molecules on cell membranes has been recently studied by fluorescence photobleaching recovery (FPR) techniques. The interpretation of these results in terms of diffusion along the membranes is based on the assumption that the surface is planar, although biological membranes may have blebs and microvilli. To study the effect of nonplanarity on the diffusion rate, the diffusio...

Lateral diffusion of membrane constituents plays an important role in membrane organization and represents a central theme in current models describing the structure and function of biological membranes. Fluorescence recovery after photobleaching (FRAP) is a widely used approach that provides information regarding dynamic properties and spatial distribution of membrane constituents. On the basi...

Hereditary spherocytosis is a common hemolytic anemia associated with deficiencies in spectrin, the principal structural protein of the erythrocyte membrane-skeleton. We have examined 20 different individuals from 10 spherocytosis kindreds and 2 elliptocytosis kindreds to determine the effects of different levels of spectrin deficiency on the viscoelastic properties of the erythrocyte membrane....

BACKGROUND AND AIM In skeletal muscles, electrical shocks may elicit acute loss of force, possibly related to increased plasma membrane permeability, induced by electroporation (EP). We explore the role of the Na(+),K(+) pumps in force recovery after EP. METHODS Isolated rat soleus or extensor digitorum longus (EDL) muscles were exposed to EP paradigms in the range 100-800 V cm(-1), and chang...

Intensive exercise leads to a loss of force, which may be long lasting and associated with muscle cell damage. To simulate this impairment and to develop means of compensating the loss of force, extensor digitorum longus muscles from 4-wk-old rats were fatigued using intermittent 40-Hz stimulation (10 s on, 30 s off). After stimulation, force recovery, cell membrane leakage, and membrane potent...