Artigos científicos, teses e dissertações
Publicados nas melhores instituições de ensino

Coincidence detection is important for functions as diverse as Hebbian learning, binaural localization, and visual attention. We show here that extremely precise coincidence detection is a natural consequence of the normal function of rectifying electrical synapses. Such synapses...

Plants have multiple potassium (K+) uptake and efflux mechanisms that are expressed throughout plant tissues to fulfill different physiological functions. Several different classes of K+ channels and carriers have been identified at the molecular level in plants. K+ transport...

1. Quisqualate- and kainate-induced currents were recorded in mouse central neurones in culture, using both 'whole-cell' and 'outside-out' configurations. Experiments were made at room temperature. 2. Both quisqualate- and kainate-induced currents invert at 0 mV when the extracel...

We have isolated cardiac cDNA and genomic clones encoding the guinea pig IsK protein. The deduced amino acid sequence is approximately 78% identical to the rat, mouse, and human variants of this channel, and the structure of the gene encoding the protein is also similar to that i...

Voltage-dependent G-protein inhibition of N-type calcium channels reduces presynaptic calcium entry, sharply attenuating neurotransmitter release. Studies in neurons demonstrate that G-proteins have multiple modulatory effects on N-type channels. The observed changes may reflect ...

1. N-Methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), and kainate receptor channels have been examined in rat cerebellar granule neurones with whole-cell and single-channel patch-clamp methods. The whole-cell peak and steady-state aspartate...

The membrane channels operated by gamma-aminobutyric acid (GABA) were studied in cultured astrocytes from rat cerebral hemispheres by using patch-clamp techniques. The channel properties appeared to be very similar, in many respects, to those present in neuronal cell membranes. T...

Ca2+-dependent inactivation of Ca2+ currents is a physiological phenomenon widely associated with L-type Ca2+ channels. Although the pore-forming α1C subunit of the channel is the target for Ca2+ binding, the amino acid sequences involved in the binding and/or in the coordination...

1. Reduction by penicillin of single gamma-aminobutyric acidA (GABAA) receptor currents from somata of mouse spinal cord neurones in culture was investigated using the excised outside-out patch-clamp recording technique. 2. GABA (2 microM) alone or with penicillin (100-5000 micro...

Closing of stomatal pores in the leaf epidermis of higher plants is mediated by long-term release of potassium and the anions chloride and malate from guard cells and by parallel metabolism of malate. Previous studies have shown that slowly activating anion channels in the plasma...

With the use of whole-cell and single-channel current recordings, we have examined in more detail the site of action of angiotensin II (AII) on multiple populations of voltage-gated calcium channels in bovine adrenal glomerulosa cells. AII (10 nM) enhances whole-cell T-type calci...

The cytoplasmic N-terminal domain of connexins has been implicated in multiple aspects of gap junction function, including connexin trafficking/assembly and channel gating. A synthetic peptide corresponding to the first 23 amino acids of human connexin37 was prepared, and circula...

The role of the tyrosine kinase p60c-src on the gating of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel was investigated with the cell-attached and excised patch clamp technique in conjunction with current noise analysis of recordings containing ...

1. Single voltage-activated K+ channels were investigated by means of the patch-clamp technique in small dorsal root ganglion (DRG) neurones in 150 microns thin slices of new-born rat DRG. It was found that K+ conductance in small DRG neurones is formed by one type of fast inacti...

Hormone secretion from chromaffin cells is evoked by calcium influx through voltage-dependent channels in the plasma membrane. Previous studies have shown that ATP, cosecreted with catecholamines from chromaffin granules, can modulate the secretion resulting from depolarization b...

1. The relationship between quantal content and prolongation of endplate currents (EPC) was studied in the frog sartorius with intact synaptic acetylcholinesterase. 2. The prolongation of EPC was more pronounced in endplates with a higher quantal content both before and after pot...

Although physiological and pharmacological evidence suggests the presence of multiple tetrodotoxin-resistant (TTX-R) Na channels in neurons of peripheral nervous system ganglia, only one, SNS/PN3, has been identified in these cells to date. We have identified and sequenced a nove...

The conduction properties of the cloned Shaker K+ channel were studied using electrophysiological techniques. Single channel conductance increases in a sublinear manner with symmetric increases in K+ activity, reaching saturation by 0.6 M K+. The Shaker K+ channel is highly selec...

We examined the impact of coexpressing the inwardly rectifying potassium channel, Kir2.3, with the scaffolding protein, synapse-associated protein (SAP) 97, and determined that coexpression of these proteins caused an approximately twofold increase in current density. A combinati...

1. Single-channel kinetics of steroid enhancement of single gamma-aminobutyric acidA (GABA) receptor currents obtained from somata of mouse spinal cord neurones in culture were investigated using the excised outside-out patch-clamp recording technique. GABA (2 microM) and GABA (2...

1. Single and multiple Ca2+ channel currents were recorded from outside-out and cell-attached patches of cultured chick and rat dorsal root ganglion cells, using the patch-clamp technique. 2. Outside-out patches containing a large number of Ca2+ channels revealed Ca2+ currents re...