Monensin, a Na(+)-selective ionophore, enhances transmitter release when applied to crustacean and frog neuromuscular junctions. Monensin is believed to raise intracellular sodium ([Na+]i) which in turn elevates intracellular calcium ([Ca2+]i). Using the fluorescent indicator fura-2, we measured [Ca2+]i in crayfish Procambarus clarkii presynaptic terminals during monensin application in normal ...

microorganisms play a major role in initiation and perpetuation of pulpal and periapical diseases. therefore, elimination of the microorganisms present in the root canal system is the fundamental objective of endodontic treatment. the use of mechanical debridement, chemical irrigation or other antimicrobial protocols and intra-canal medicaments are critical to attain this goal. the aim of this ...

Voltage-gated sodium channels initiate action potentials in nerve, muscle, and other electrically excitable cells. Voltage-gated calcium channels are activated by depolarization during action potentials, and calcium influx through them is the key second messenger of electrical signaling, initiating secretion, contraction, neurotransmission, gene transcription, and many other intracellular proce...

Calcium binding to sarcolemma-enriched preparations from canine ventricle was evaluated. The preparation was exposed to calcium and 45Ca at physiological ionic strength, pH 7.4, for 15-18 hours at 5 degrees C. Bound calcium was separated from free by filtration and washing of the filter with solutions containing calcium and LaCl3. After equilibration at 5 degrees C, exposure to 37 degrees C cau...

Reducing the sodium content of medium bathing isolated guinea pig atria produces a positive inotropic response associated with a marked decline in action potential amplitude and a decrease in relaxation velocity. The effects of sodium reduction appear to result from a decline in the rate of sodium-dependent calcium efflux across the sarcolemma. Consistent with this hypothesis, caffeine, which m...

Electrical stimulation of isolated adult rat heart cells in suspension at 4 Hz resulted in a fourfold increase in the rate of sodium influx and efflux across the sarcolemma, with no change in total cell sodium, as measured with 22Na. The magnitude of stimulation-dependent sodium fluxes under these conditions averaged 17 nmol/min/mg protein. The increased rate of efflux was inhibited by tetrodot...

in this study formation and properties of o/w emulsion stabilized by a mixture of sodium caseinate (2, 5 and 10 wt %) and non-ionic emulsifier tween 80, sorbitan mono-9-octadecenoate, (0, 0.5, 1 and 1.5 wt %) were investigated at various ph values(3, 5 and 7) and calcium ion concentrations (0, 0.2, 0.4 and 0.6 wt%). emulsion samples were prepared by using a sonicator with a nominal power output...

Some biological aspects of semen were investigated in the Persian sturgeon, Acipenser persicus, by determination of seminal plasma indices (ionic composition and osmolality), sperm density and their relationships with sperm motility. The osmolality of seminal plasma ranged from 42.00 to 111.00 mOsmol Kg-1. The concentrations of Sodium (Na+), Potassium (K+), Chloride (Cl-), Calcium (Ca2+) and Ma...