Desheathed frog (R. pipiens) sciatic nerves were soaked in Na-deficient solutions, and measurements were made of their Na and K contents and of the movements of K(42). When a nerve is in Ringer's solution, the Na fluxes are equal to the K fluxes, and about 75 per cent of the K influx is due to active transport. The Na content and the Na efflux are linearly related to the Na concentration of the...

A single Na(+)/K(+)-ATPase pumps three Na(+) outwards and two K(+) inwards by alternately exposing ion-binding sites to opposite sides of the membrane in a conformational sequence coupled to pump autophosphorylation from ATP and auto-dephosphorylation. The larger flow of Na(+) than K(+) generates outward current across the cell membrane. Less well understood is the ability of Na(+)/K(+) pumps t...

To test Joossens's hypothesis that salt is a common cause of both cerebrovascular disease (CVD) and stomach cancer (SC), the standardized mortality ratios (SMRs) of SC and CVD were related to urinary Na and K and urinary Na/creatinine (Cr), K/Cr, and Na/K ratios. Fifty spot urine of females between 40 to 69 years was collected from each of 169 municipalities (88 urban and 81 rural) covering all...

Alveolar epithelial cells effect edema clearance by transporting Na(+) and liquid out of the air spaces. Active Na(+) transport by the basolaterally located Na(+)-K(+)-ATPase is an important contributor to lung edema clearance. Because alveoli undergo cyclic stretch in vivo, we investigated the role of cyclic stretch in the regulation of Na(+)-K(+)-ATPase activity in alveolar epithelial cells. ...

Na/K pump activity and metabolic rate are both higher during the day in the suprachiasmatic nucleus (SCN) that houses the circadian clock. Here we investigated the role of intracellular Na(+) and energy metabolism in regulating Na/K pump activity and neuronal excitability. Removal of extracellular K(+) to block the Na/K pump excited SCN neurons to fire at higher rates and return to normal K(+) ...

40 41 Na/K pump activity and metabolic rate are both higher at day in the suprachiasmatic nucleus 42 (SCN) that houses the circadian clock. Here we investigated the role of intracellular Na and 43 energy metabolism in regulating Na/K pump activity and neuronal excitability. Removal of 44 extracellular K to block the Na/K pump excited SCN neurons to fire at higher rates and return 45 to normal K...

During excitation, muscle cells gain Na(+) and lose K(+), leading to a rise in extracellular K(+) ([K(+)]o), depolarization, and loss of excitability. Recent studies support the idea that these events are important causes of muscle fatigue and that full use of the Na(+),K(+)-ATPase (also known as the Na(+),K(+) pump) is often essential for adequate clearance of extracellular K(+). As a result o...

1 A specific and essential role for Na,K-ATPase α3 in neurons co-expressing α1 and α3* Background: Neurons express two Na,K-ATPase isoforms, the ubiquitous α1 and neuron-specific α3. Result: α3 is important for control of membrane potential and is fully responsible for restoration of large [Na + ] i increases. Conclusion: α1 and α3 are required for basal neuronal function, but α3 controls resto...

in a greenhouse experiment, the effects of waterlogging, sewage sludge and manure on the uptake and concentrations of p, k, ca, mg and na in root and shoot of sunflower (helianthus annuus l.) were investigated. a factorial experiment based on completely randomized design with three replications including duration of waterlogging at five levels (0, 2, 4, 8, 22 days), source of organic fertilizer...

Voltage-gated potassium (K+) channels are multi-ion pores. Recent studies suggest that, similar to calcium channels, competition between ionic species for intrapore binding sites may contribute to ionic selectivity in at least some K+ channels. Molecular studies suggest that a putative constricted region of the pore, which is presumably the site of selectivity, may be as short as one ionic diam...