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1. Single giant barnacle muscle fibres from Megabalanus psittacus (Darwin) were used to measure the Ca entry and the development of tension in the fibres under membrane potential control.2. Fibres bathing in 60 mm-MgCl(2) sea water, free of Ca, did not develop tension with sudden displacements of the membrane potential towards more positive values. This(More)
Intramembrane charge movements in skeletal muscle fibers contain a tetracaine-sensitive component that can be isolated by the use of this drug. The time course and voltage dependence of this component, studied in relation to antipyrylazo III absorbance signals, suggest its direct involvement in the calcium release process in muscle.
1. Single barnacle muscle fibres from Megabalanus psittacus (Darwin) were internally perfused and the effects of various internal and external solutions on voltage clamp currents were examined.2. The usual internal solution was 180 mM-K(+) aspartate (osmotic pressure adjusted to 1000 m-osmole by adding sucrose). Fibres perfused with this solution gave an(More)
A method is presented for recording extrinsic optical signals from segments of single skeletal muscle fibers under current or voltage clamp conditions. Such segments, which are cut from intact fibers, are maintained in a relaxed state, while exhbiting otherwise normal physiological properties, including healthy delayed rectifier currents. Extrinsic(More)
The development of immune responses to malarial infection in inhabitants of endemic areas differs according to the level of exposure to the parasite. Adults living in a region where the level of malaria transmission is low (Colombia) have been shown to exhibit a similar response to each of the three regions of the circumsporozoite protein (the central(More)
Ca2+-selective electrodes have been used to measure free intracellular Ca2+ concentrations in squid giant axons. Electrodes made of glass cannulas of about 20 microns in diameter, plugged with a poly(vinyl chloride) gelled sensor were used to impale the axons axially. They showed a Nernstian response to Ca2+ down to about 3 microM in solutions containing(More)
Plasma samples of individuals from two malaria-endemic villages on the Colombian Pacific coast and synthetic peptides representing different fragments of the central and flanking regions of the Plasmodium vivax circumsporozoite protein (CSP) were used to perform a fine mapping of the B-cell epitopes on the whole CSP. In addition, the immunogenicity of long(More)
Mg2+-selective microelectrodes have been used to measure the intracellular free Mg2+ concentration in frog skeletal muscle fibers. Glass capillaries with a tip diameter of less than 0.4 micron were backfilled with the Mg2+ sensor, ETH 1117. In the absence of interfering ions, they gave Nernstian responses between 1 and 10 mM free Mg2+. In the presence of an(More)