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J A Argibay

Publications and source records attributed to J A Argibay.

28 records · Page 2Linked to original sources
PubMed1985

Inward rectification in muscle fibres of the toad Bufo marinus.

Inward rectification of the resting potassium conductance was studied in skeletal muscle fibres of the toad Bufo marinus. This conductance was shown to be blocked by Ba and Cs and located both in the surface membrane and the membranes of the tubular system. Some differences were found between the properties of this conductance channel in Bufo marinus and those reported for various species of Rana. The possible adaptative value of these differences is pointed out.

Animals↗
PubMed1984

Sodium currents in skeletal muscle fibres from the toad Bufo marinus.

Single fibres from the sartorius muscle of the toad Bufo marinus were used to study ionic currents, using a fast voltage-clamp method. Sodium currents were analysed following Hodgkin-Huxley formulations. Internal caesium fluoride blocks delayed currents but produced shifts in the equilibrium potential of the early channel due to sodium accumulation. Delayed channels are very unstable when fluoride is used inside the fibre. These instabilities and equilibrium potential shifts were eliminated on replacing fluoride by aspartate in the internal solution. Late peaks of inward current, probably associated with activity at the tubular system, were occasionally observed for small depolarizations. The results are compared with those obtained for other amphibian species and used to explain more general electrophysiological properties of muscle fibres of this tropical toad.

Animals↗
PubMed1983

Block by Cs of K current iK1 and of carbachol induced K current iCch in frog atrium.

1. In frog atrium, Cs ions block both the inward rectifier iK1 and the carbachol induced K current iCch. 2. Both iK1 and iCch display a high affinity for Cs with a K0.5 of 4 X 10(-5) M for iK1 and of 8 X 10(-5) M for iCch at V = -50 mV. 3. Block of both iK1 and iCch is strongly voltage dependent. When fitted by the block model of Woodhull (1973), delta is greater than 1 for the two currents. 4. From these similarities, action of Cch on frog atrium K permeability could be interpreted as a modification of iK1.

Animals↗