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...

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...

The flash-induced Ca(2+)- and Na(+)-influx and Na+/Ca(2+)-exchange activity in blowfly Calliphora photoreceptors were investigated. The change in membrane potential, induced by a bright flash, was intracellularly measured in vivo. Based on a biophysical photoreceptor model, the Na(+)- and Ca(2+)-currents and concentration changes were determined from the first transient depolarization phase of ...

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...

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...

Hurtado, Jose, Salvador Borges, and Martin Wilson. Na -Ca exchanger controls the gain of the Ca amplifier in the dendrites of amacrine cells J Neurophysiol 88: 2765–2777, 2002; 10.1152/jn.00130.2002. We have previously shown that disabling forward-mode Na -Ca exchange in amacrine cells greatly prolongs the depolarization-induced release of transmitter. To investigate the mechanism for this, we ...

Months after sacral spinal transection in rats (chronic spinal rats), motoneurons below the injury exhibit large, low-threshold persistent inward currents (PICs), composed of persistent sodium currents (Na PICs) and persistent calcium currents (Ca PICs). Here, we studied whether motoneurons of normal adult rats also exhibited Na and Ca PICs when the spinal cord was acutely transected at the sac...

Calcium has a fundamental role in the cellular processes of ion absorption and retention. The ion is generally credited with lhaving beneficial effects on the semipermeability of membranes and structure of protoplasm (9,12). The electron microscope shows Ca deficiency to result in (lisorganization of membrane structure (19). In addition, the presence of calcium in solution was found by Viets (2...