María Teresa Pérez-García

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1. The sodium channel has a ring of negatively charged amino acids on its external face. This common structural feature of cation-selective channels has been proposed to optimize conduction by electrostatic attraction of permeant cations into the channel mouth. We tested this idea by mutagenesis of mu1 rat skeletal sodium channels expressed in Xenopus(More)
The carotid body (CB) chemoreceptors participate in the ventilatory responses to acute and chronic hypoxia (CH). Arterial hypoxaemia increases breathing within seconds, and CB chemoreceptors are the principal contributors to this reflex hyperventilatory response. Acute hypoxia induces depolarization of CB chemoreceptors by inhibiting certain K+ channels,(More)
The cardiac dihydropyridine-sensitive calcium channel was transiently expressed in HEK293 cells by transfecting the rabbit cardiac calcium channel alpha 1 subunit (alpha 1C) alone or in combination with the rabbit calcium channel beta subunit cloned from skeletal muscle. Transfection with alpha 1C alone leads to the expression of inward, voltage-activated,(More)
1. Coexpression of the beta subunit with the alpha 1C subunit of the cardiac L-type Ca2+ channel has been shown to increase ionic current. To examine the mechanism of this increase, ionic and gating currents were measured in transiently transfected HEK293 cells. 2. Beta 1A subunit coexpression increased the maximal whole-cell conductance (Gmax) measured in(More)
The pores of voltage-gated cation channels are formed by four intramembrane segments that impart selectivity and conductance. Remarkably little is known about the higher order structure of these critical pore-lining or P segments. Serial cysteine mutagenesis reveals a pattern of side-chain accessibility that contradicts currently favored structural models(More)
1. The electrical properties of chemoreceptor cells from neonatal rat and adult rabbit carotid bodies (CBs) are strikingly different. These differences have been suggested to be developmental and/or species related. To distinguish between the two possibilities, the whole-cell configuration of the patch-clamp technique was used to characterize the ionic(More)
Voltage-gated K+ (KV) channels are protein complexes composed of ion-conducting integral membrane alpha subunits and cytoplasmic modulatory beta subunits. The differential expression and association of alpha and beta subunits seems to contribute significantly to the complexity and heterogeneity of KV channels in excitable cells, and their functional(More)
Native cardiac and skeletal muscle Na channels are complexes of alpha and beta 1 subunits. While structural correlates for activation, inactivation, and permeation have been identified in the alpha subunit and the expression of alpha alone produces functional channels, beta 1-deficient rat skeletal muscle (mu 1) and brain Na channels expressed in Xenopus(More)
A conserved lysine residue in the "P loop" of domain III renders sodium channels highly selective. Conversion of this residue to glutamate, to mimic the homologous position in calcium channels, enables Ca2+ to permeate sodium channels. Because the lysine-to-glutamate mutation converts a positively charged side chain to a negative one, it has been proposed(More)
We have investigated the effects of different treatments that increase cyclic AMP levels on the in vitro synthesis and release of catecholamines in the rabbit carotid body. We also measured the rate of 45Ca2+ efflux from previously loaded carotid bodies under different conditions. Forskolin produced a dose-dependent increase in the release of [3H]dopamine(More)