Identification of inwardly rectifying potassium channels in bovine retinal and choroidal endothelial cells.

Ion channels were studied using the whole-cell patch clamp technique in bovine retinal and choroidal microvascular endothelial cells (MVEC) cultured under the same conditions. The two types of MVEC expressed inward currents at hyperpolarizing voltage steps and showed small outward currents at depolarizing steps. The extrapolated reversal potentials of the inward currents were near to the potassium equilibrium potential.

Voltage-dependent potassium channels in cytokeratin-positive and cytokeratin-negative microvascular endothelial cells of the corpus luteum.

We have recently described cytokeratin-positive (CK(+)) and cytokeratin-negative (CK(-)) microvascular endothelial cells (MVECs) in the bovine corpus luteum. The two phenotypes show a different expression and release of adhesion molecules and cytokines. Since secretion of mediators is specifically regulated by the electrophysiological membrane parameters, this report will compare voltage-dependent potassium (K(+)) channels in the two cell types cultured under the same conditions.

Pharmacological characterization of the P2X(7) receptor on human macrophages using the patch-clamp technique.

Whole-cell patch-clamp recordings were made from macrophages derived from human monocytes that had been cultured for 5-7 days. The P2X agonists ATP (100 microM) and 2',3'-(4-benzoyl)-benzoyl ATP (BzATP, 100 microM) induced inward currents. A second application of the agonists was characterized by strong desensitisation of the maximum current.

Effect of an adenosine A(1) receptor agonist and a novel pyrimidoindole on membrane properties and neurotransmitter release in rat cortical and hippocampal neurons.

Activation of adenosine A(1) receptors by endogenous adenosine plays a neuroprotective role under various pathophysiological conditions including hypoxia. Intracellular recordings were made in rat pyramidal cells of the somatosensory cortex. Hypoxia (5 min) induced a membrane depolarization and a decrease of input resistance.

Adenosine A(1) and A(3) receptors mediate inhibition of synaptic transmission in rat cortical neurons.

Intracellular recordings were made in rat brain slice preparations containing pyramidal cells of the associative frontal cortex in order to characterize the action of selective adenosine A(1) and A(3) receptor ligands on synaptic neurotransmission. The selective A(1) receptor agonist N(6)-cyclopentyladenosine (CPA) inhibited concentration-dependently the excitatory postsynaptic potentials (PSPs) which were evoked by focal electrical stimulation. The CPA-mediated inhibition was blocked by 1, 3-dipropyl-8-cyclopentylxanthine (DPCPX), a highly A(1) receptor-selective antagonist.