We previously showed that rat taste buds express several adenylyl cyclases (ACs) of which, only AC8 is known to be stimulated by Ca 2+. Here, we demonstrate by direct measurements of cAMP levels, that AC activity in taste buds is stimulated by treatments that elevate intracellular Ca 2+. Specifically, 5 :M thapsigargin or 3 :M A23187 (calcium ionophore), both of which increase [Ca 2+ ] i , lead...

Rat diaphragms depleted of calcium involved in excitation-contraction (E-C calcium) coupling were tagged with Ca. Seventy percent of the Ca was extracted by a 25 HIM NaHCOs-50% glycerol solution. Treatment of the muscles with caffeine, shown previously to release E-C calcium, decreased extractable Ca to about one-fourth of that of control muscles, indicating that a large fraction of the extract...

Spontaneous release of glutamate is important for maintaining synaptic strength and controlling spike timing in the brain. Mechanisms regulating spontaneous exocytosis remain poorly understood. Extracellular calcium concentration ([Ca(2+)](o)) regulates Ca(2+) entry through voltage-activated calcium channels (VACCs) and consequently is a pivotal determinant of action potential-evoked vesicle fu...

Inactivation of voltage-gated calcium channels is crucial for the spatiotemporal coordination of calcium signals and prevention of toxic calcium buildup. Only one member of the highly conserved family of calcium channel beta-subunits--Ca(V)beta--inhibits inactivation. This unique property has been attributed to short variable regions of the protein; however, here we report that this inhibition ...

The role of parathyroid hormone-related protein (PTHrP) in fetal calcium homeostasis and placental calcium transport was examined in mice homozygous for the deletion of the PTHrP gene (PTHrP-/- null; NL) compared to PTHrP+/+ (wild-type; WT) and PTHrP+/- (heterozygous; HZ) littermates. Fetal blood ionized calcium was significantly reduced in NL fetuses compared to WT and HZ groups at 18 days of ...

Ca(2+) sparks and Ca(2+) waves play important roles in calcium release and calcium propagation during the excitation-contraction (EC) coupling process in cardiac myocytes. Although the classical Fick's law is widely used to model Ca(2+) sparks and Ca(2+) waves in cardiac myocytes, it fails to reasonably explain the full-width at half maximum(FWHM) paradox. However, the anomalous subdiffusion mo...

It is well-known that the opening of L-type voltage-gated calcium channels can be regulated by calmodulin (CaM). One of the main regulatory mechanisms is calcium-dependent inactivation (CDI), where binding of apo-CaM to the cytoplasmic C-terminal domain of the channel can effectively sense an increase in the local calcium ion concentration. Calcium-bound CaM can bind to the IQ-motif region of t...

UNLABELLED Calcium is one of the key elements to consider in patients on dialysis due to its relationship with cardiovascular risk. The introduction of non-calcium-based phosphate binders and calcimimetics has changed the setting for pre-dialysis serum calcium in recent years from 9.5-10.5mg/dl to 8.5-9.5mg/dl. To assess more accurately the changes in calcium (Ca) during haemodialysis sessions ...