Juan Vicente Sánchez-Andrés

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Glutamate controls the induction of GABA-mediated giant depolarizing potentials through AMPA receptors in neonatal rat hippocampal slices. Giant depolarizing potentials (GDPs) are generated by the interplay of the depolarizing action of GABA and glutamate. In this study, single and dual whole cell recordings (in current-clamp configuration) were performed(More)
1. Pancreatic beta-cells oscillate synchronously when grouped in islets. Coupling seems essential to maintain this oscillatory behaviour, as isolated cells are unable to oscillate. This allows the islet to be used as a model system for studying the role of coupling in the generation of oscillatory patterns. 2. Pairs of beta-cells were intracellularly(More)
1. The characteristics of the electrical activity of beta-cells from islets of Langerhans recorded in vivo are described. For blood glucose concentrations from 4 to 11 mM, the electrical activity of pancreatic beta-cells is oscillatory, with alternating depolarized and hyperpolarized phases. During the depolarized phases, action potentials are triggered. 2.(More)
For a constant membrane potential, a predominantly inhibitory GABAergic synaptic response is shown to undergo long-term transformation into an excitatory response after pairing of exogenous gamma-aminobutyric acid (GABA) with postsynaptic depolarization or pairing of pre- and postsynaptic stimulation. Current- and voltage-clamp experiments suggest that this(More)
1. The properties of the oscillations in electrical activity of different beta-cells within the same islet of Langerhans, and of different islets within the same pancreas, recorded in vivo, are described. 2. Simultaneous recordings of two cells within the same islet showed that the oscillations were synchronous. A rapid increase in blood glucose led to the(More)
Pancreatic islets are neuroendocrine organs that control blood glucose homeostasis. The precise interplay of a heterogeneous group of cell populations (β, α, δ and PP cells) results in the fine-tuned release of counterbalanced hormones (insulin, glucagon, somatostatin and pancreatic polypeptide respectively). Under the premises of detailed knowledge of the(More)
The cerebellum has been directly implicated in the associative learning exemplified by classical conditioning of the rabbit nictitating membrane response. Lesions of cerebellar lobule HVI (Lobulus simplex) can disrupt or even abolish classical conditioning. Electrical stimulation of inputs that converge at cerebellar lobule HVI and the deep cerebellar(More)
1. N-type (omega-conotoxin sensitive) calcium currents (ICa) were recorded in identified neurons in Hermissenda crassicornis using low-resistance patch electrodes (0.7 +/- 0.3 M omega; n = 101) under conditions that eliminated inward Na+ currents (choline ions substitution) and suppressed outward K+ currents (Cs+, tetraethylammonium, and 4-AP). Step(More)
Proper insulin secretion requires the coordinated functioning of the numerous beta cells that form pancreatic islets. This coordination depends on a network of communication mechanisms whereby beta cells interact with extracellular signals and adjacent cells via connexin channels. To assess whether connexin-dependent communication plays a role in vivo, we(More)
Under normal conditions, hippocampal slices from newborn rats and rabbits (postnatal days 0-8) show spontaneous synchronous bursts known as giant depolarizing potentials. These bursts are recorded from CA3, CA1 and the fascia dentata in both intact slices and isolated hipocampal regions. Giant depolarizing potentials are network-driven events resulting from(More)