The present series of experiments have served to elucidate unequivocally that the performance of isolated frog's heart improves considerably on reduction of sodium chloride to 60 mM/L in the perfusate, and that probably this improvement is not affected by the presence of disaccharides and glucose added to the perfusate so as to maintain isotonicity, although further work is required to corrobor...

The effect of the extracellular Ca depletion on potassium contracture was investigated in single fibers isolated from frog semitendinosus muscle mainly in relation to its time and Na dependency. The shortening of plateau duration and the increase in the rate of relaxation of the potassium contracture appeared within 3--5 sec and 15 sec, respectively, after the fiber was immersed in Ca-free Na R...

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 ...

Axonal growth and targeting are fundamental to the organization of the nervous system, and require active engagement of the cytoskeleton. Polymerization and stabilization of axonal microtubules is central to axonal growth and maturation of neuronal connectivity. Studies have suggested that members of the tubulin polymerization promoting protein (TPPP, also known as P25α) family are involved in ...

background spinal anesthesia is an important and commonly used method for surgical anesthetic in operating rooms. however, even with identical drug dosage and administration mode, the extent of drug distribution in vivo is highly variable and difficult to control. preanesthetic administration of fluids immediately before spinal anesthesia (preload) is normal practice. the choice of fluid type m...

1. Electrophysiological techniques have been applied to tsetse fly Malpighian tubules for the first time. 2. In either Cl- or SO42- Ringer, both non-perfused and perfused tubules displayed transtubular potentials (Vt) at or close to 0 mV. Exposure to cyclic AMP elicited a marked secretory response and, in SO42- Ringer, a sharp (lumen-positive) increase in Vt. In Cl- Ringer, despite more than do...