Flor V. Barnola

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Sodium channel activity was determined by measuring the veratridine-tetrodotoxin-sensitive sodium influx in reconstituted vesicles prepared from lobster nerve membrane and soybean lipids. The sodium channel activity was abolished by treatment of membranes, prior to reconstitution, with purified phospholipase A2. When the treatment with phospholipase A2 was(More)
Experiments were carried out to investigate possible interactions of tetrodotoxin (TTX) with lipid molecules isolated from nerve fiber plasma membranes of the squid Dosidicus gigas. TTX has a highly selective ability to block the channel normally used by Na(+) to cross the axolemma during nervous impulse conduction. In order to investigate the interaction(More)
A (Ca2+, Mg2+)-ATPase activity and a (Ca2+, Mg2+)-dependent phosphorylation from ATP have been found in plasma membrane fragments from squid optical nerves under conditions where contamination by intracellular organelles is unlikely. The properties of this (Ca2+, Mg2+)-ATPase activity are almost identical to those of the ATP-dependent uncoupled Ca2+ efflux(More)
Saxitoxin (STX) and tetrodotoxin (TTX) have the same striking property of blocking the Na+ channels in the axolemma. Experiments with nerve plasma membrane components of the squid Dosidicus gigas have shown that TTX interacts with cholesterol monolayers. Similar experiments were carried out with STX. The effect of STX on the surface pressure-area diagrams(More)
The efflux of 22Na from vesicles formed by axolemma fragments isolated from lobster nerves was studied in the presence and in the absence of drugs having well-known action on the sodium channels. The vesicles were equilibrated 12-14 h at 4 degrees C with 22Na in lobster solution containing 1 mM ouabain. Afterwards the suspension was divided: one portion was(More)