Calcium-dependent repolarization inParamecium

Calcium-dependent modulation of the cardiac repolarization

Characterizing the contribution of voltage- and calcium-dependent coupling to action potential stability: implications for repolarization alternans.

Experiments have provided suggestive but inconclusive insights into the relative contributions of transmembrane voltage and intracellular calcium handling to the development of cardiac electrical instabilities such as repolarization alternans. In this study, we applied a novel combination of techniques (action potential voltage clamping, calcium-transient clamping, and stability analysis) to ca...

Voltage-dependent calcium channels.

Voltage-activated calcium channels can be divided into two subgroups based on their activation threshold, low-voltage-activated (LVA) and high-voltage-activated (HVA). Auxiliary subunits of the HVA calcium channels contribute significantly to biophysical properties of the channels. We have cloned and characterized members of two families of auxiliary subunits: alpha2delta and gamma. Two new alp...

Receptor-dependent Calcium Signaling

The inositol 1,4,5-trisphosphate (InsP 3 )-gated Ca channel in cerebellum is tightly regulated by Ca (Bezprozvanny, I., J. Watras, and B.E. Ehrlich. 1991. Nature (Lond.). 351:751–754; Finch, E.A., T.J. Turner, and S.M. Goldin. 1991. Science (Wash. DC). 252:443–446; Hannaert-Merah, Z., J.F. Coquil, L. Combettes, M. Claret, J.P. Mauger, and P. Champeil. 1994. J. Biol. Chem. 269:29642–29649; Iino,...

Calcium-dependent Action of Osmolality

osmolality is decreased from 1,650 to 305 mosM. Incubation of slices in Ca2+-free media containing 2 mM EGTA largely abolished this action of osmolality on cAMP, whereas exclusion of Mg2+ or K+ from the incubation media was without effect. Addition of Ca21 to Ca2+-deprived inner medulla incubated at 750 mosM (175 mM Na+, 380 mM urea) significantly increased tissue cAMP and media prostaglandin (...