Na, K and Cl measurements have been made on frozen sections of chick red blood cells throughout embryonic development, using electron-probe microanalysis. There is an apparent fluctuation in the levels of these elements during maturation, although the Na/K ratio remains fairly constant. The nuclear Na concentration resembles that of the cytoplasm, rather than that of the medium, at all stages. ...

Two recent studies reported that Na-Ca exchange in the outer segments of tiger salamander rod photoreceptors (Cervetto, L., Lagnado, L., Perry, R. J., Robinson, D. W., and McNaughton, P. A. (1989) Nature 337, 740-743) and of bovine rod photoreceptors (Schnetkamp, P. P. M., Basu, D. K., and Szerencsei, R. T. (1989) Am. J. Physiol. 257, C153-157) requires and transports K+ in a 4Na/(1Ca+1K) stoic...

OBJECTIVE To examine the contribution of reverse mode sodium-calcium (Na-Ca) exchange to contractions in isolated left-ventricular myocytes from failing human heart. METHODS Low resistance patch pipettes were used to dialyze cells with Na-free or high-Na pipette solution ([Na]pipette = 0 and 20 mmol/L, respectively) to reduce or enhance Na-Ca exchange. Whole-cell membrane-potential, membrane-...

To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for tapirs (Tapirus spp.), we investigated the apparent absorption (aA) of macro and micro-minerals in 18 tapirs from five zoological institutions in a total of 24 feeding trials with total faecal collection. Samples of feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Cu and Zn. The res...

Morbus Alzheimer neuropathology is characterized by an impaired energy homeostasis of brain tissue. We present an approach towards a potential therapy of Alzheimer disease based on the high-energy polymer inorganic polyphosphate (polyP), which physiologically occurs both in the extracellular and in the intracellular space. Rat pheochromocytoma (PC) 12 cells, as well as rat primary cortical neur...

Ventricular arrhythmias commonly originate from the right ventricular out-flow tract (RVOT). However, the electrophysiological characteristics and Ca(2+) homoeostasis of RVOT cardiomyocytes remain unclear. Whole-cell patch clamp and indo-1 fluorometric ratio techniques were used to investigate action potentials, Ca(2+) homoeostasis and ionic currents in isolated cardiomyocytes from the rabbit R...

dry land salinity is one of the major problems affecting agricultural products. the main consequences of plant exposure to salt stress are water deficit and ion excess, which lead to several morphological and physiological changes. in order to evaluate the effect of salinity on some physiological characteristics of 8 spring rapeseed cultivars, an experiment was conducted in the greenhouse at ya...

matricaria chamomilla is a medicinal plant that is widely cultivated in salt affected soils. this investigation was undertaken to study the effect of nacl concentration on germination, and the physiological, biochemical and growth characteristics of chamomile. seed germination and growth were studied at five nacl concentration levels (0, 40, 80, 120 and 190 mm nacl concentration). increasing th...

Studies on HeLa cells in spinner culture at pH 7.0 and 37 degrees have shown that [Na](i) decreased and [K](i) increased with increasing [Ca](o). In Na-free (choline) medium [K](i) remained high whether or not Ca was present in the medium. [Na](i) and [K](i) approached a new steady state within 1 min after transfer to Ca-free medium and returned to the initial values within 15 min upon readditi...