[Preventive effects of jinghua weikang capsule on NSAID-induced injury to the mucosa of the small intestine: an experimental research].

Objective: To study the preventive effects of jinghua weikang capsule (JWC) on nonsteroidal anti-inflammatory drugs (NSAIDs) induced injury to the mucosa of the small intestine.

Methods: Thirty-two Wistar rats were randomly divided into four groups, i.e.

Comparison of the effects of DC031050, a class III antiarrhythmic agent, on hERG channel and three neuronal potassium channels.

Aim: This study was conducted to test the selectivity of DC031050 on cardiac and neuronal potassium channels.

Methods: Human ether-à-go-go related gene (hERG), KCNQ and Kv1.2 channels were expressed in CHO cells.

SKF83959 suppresses excitatory synaptic transmission in rat hippocampus via a dopamine receptor-independent mechanism.

Dopamine (DA) profoundly modulates excitatory synaptic transmission and synaptic plasticity in the brain. In the present study the effects of SKF83959, the selective agonist of phosphatidylinositol (PI)-linked D(1) -like receptor, on the excitatory synaptic transmission were investigated in rat hippocampus. SKF83959 (10-100 μM) reversibly suppressed the field excitatory postsynaptic potential (fEPSP) elicited by stimulating the Schaffer's collateral-commissural fibers in CA1 area of hippocampal slices.

Electrophysiological effects of SKF83959 on hippocampal CA1 pyramidal neurons: potential mechanisms for the drug's neuroprotective effects.

Although the potent anti-parkinsonian action of the atypical D₁-like receptor agonist SKF83959 has been attributed to the selective activation of phosphoinositol(PI)-linked D₁ receptor, whereas the mechanism underlying its potent neuroprotective effect is not fully understood. In the present study, the actions of SKF83959 on neuronal membrane potential and neuronal excitability were investigated in CA1 pyramidal neurons of rat hippocampal slices. SKF83959 (10-100 µM) caused a concentration-dependent depolarization, associated with a reduction of input resistance in CA1 pyramidal neurons.

Incompatibility behavior of a symbiotic plasmid pMH7653Rb in Mesorhizobium huakuii 7653R.

Mesorhizobium huakuii strain 7653R harbored two indigenous plasmids named pMH7653Ra and pMH7653Rb. The larger plasmid pMH7653Rb (symbiotic plasmid) was transferred to M. huakuii HN308SR harboring three plasmids: pMHHN308a, pMHHN308b and pMHHN308c, and HN3015SR harboring three plasmids: pMHHN3015a, pMHHN3015b and pMHHN3015c by tri-parent mating.

Magnesium lithospermate B dilates mesenteric arteries by activating BKCa currents and contracts arteries by inhibiting K(V) currents.

Aim: To examine the involvement of K(+) channels and endothelium in the vascular effects of magnesium lithospermate B (MLB), a hydrophilic active component of Salviae miltiorrhiza Radix.

Methods: Isolated rat mesenteric artery rings were employed to investigate the effects of MLB on KCl- or norepinephrine-induced contractions. Conventional whole-cell patch-clamp technique was used to study the effects of MLB on K(+) currents in single isolated mesenteric artery myocytes.

Activation of phosphatidylinositol-linked D1-like receptors increases spontaneous glutamate release in rat somatosensory cortical neurons in vitro.

Central dopaminergic system exerts profound modulation on spontaneous glutamate release in various brain regions mainly through D(1) receptor/cAMP/PKA pathway. It remains unclear whether the phosphatidylinositol (PI)-linked D(1)-like receptors are also involved in such modulatory actions. The identification of substituted phenylbenzazepine SKF83959 as the selective agonist for the atypical D(1)-like receptors has given impetus to study their influence on the spontaneous glutamate release in the brain.

Arylbenzazepines are potent modulators for the delayed rectifier K+ channel: a potential mechanism for their neuroprotective effects.

(+/-) SKF83959, like many other arylbenzazepines, elicits powerful neuroprotection in vitro and in vivo. The neuroprotective action of the compound was found to partially depend on its D(1)-like dopamine receptor agonistic activity. The precise mechanism for the (+/-) SKF83959-mediated neuroprotection remains elusive.

Electrophysiological characterization of a novel Kv channel blocker N,N'-[oxybis(2,1-ethanediyloxy-2,1-ethanediyl) ]bis(4-methyl)-benzenesulfonamide found in virtual screening.

Aim: N,No-[oxybis(2,1-ethanediyloxy-2,1-ethanediyl)]bis(4-methyl)- benzenesulfonamide (OMBSA) is a hit compound with potent voltage-gated K+ (Kv) channel-blocking activities that was found while searching the MDL Available Chemicals Directory with a virtual screening approach. In the present study, the blocking actions of OMBSA on Kv channels and relevant mechanisms were characterized.

Methods: Whole-cell voltage-clamp recording was made in acutely dissociated hippocampal CA1 pyramidal neurons of newborn rats.

Electrophysiological actions of cyclosporin A and tacrolimus on rat hippocampal CA1 pyramidal neurons.

Aim: The aim of the present study was to investigate the electrophysiological actions of cyclosporin A (CsA) and tacrolimus (FK506) on neurons in the brain, and to elucidate the relevant mechanisms.

Methods: Whole-cell current-clamp recording was made in CA1 pyramidal neurons in rat hippocampal slices; whole-cell voltage-clamp recording was made in dissociated hippocampal CA1 pyramidal neurons of rats.

Results: CsA (100 micromol/L) and FK506 (50 micromol/L) did not significantly alter the passive electrical properties of hippocampal CA1 pyramidal neurons, but slowed down the repolarizing phase of the action potential.

Calcineurin-independent inhibition of the delayed rectifier K+ current by the immunosuppressant FK506 in rat hippocampal neurons.

The immunosuppressant drug FK506 was found to be a potent neuroprotective agent in animal models of brain ischemia. However, the mechanisms underlying the action remain to be elucidated. The delayed rectifier K(+) channel has been implicated in ischemic injury and neuronal death in the brain.

Chlorahololides A and B, two potent and selective blockers of the potassium channel isolated from Chloranthus holostegius.

[structure: see text] Chlorahololides A(1) and B(2), two highly complex sesquiterpenoid dimers, were isolated from Chloranthus holostegius. Their structures and absolute configurations were established by NMR spectroscopy, X-ray crystallography, and CD. Chlorahololides A (1) and B (2) exhibited potent and selective inhibition on the delayed rectifier (IK) K+ current, with an IC50 of 10.

Discovering potassium channel blockers from synthetic compound database by using structure-based virtual screening in conjunction with electrophysiological assay.

Potassium ion (K+) channels are attractive targets for drug discovery because of the essential roles played in biological systems. However, high-throughput screening (HTS) cannot be used to screen K+ channel blockers. To overcome this disadvantage of HTS, we have developed a virtual screening approach for discovering novel blockers of K+ channels.

Inhibition of excitatory synaptic transmission by trans-resveratrol in rat hippocampus.

The red wine polyphenol trans-resveratrol has been found to exert potent protective actions in a variety of cerebral ischemia models. The neuroprotection by trans-resveratrol thus far is mainly attributed to its intrinsic antioxidant properties. In the present study, the effects of the red wine polyphenol on excitatory synaptic transmission were investigated in the CA1 region of rat hippocampal slices.

Electrophysiological characterization of 14-benzoyltalatisamine, a selective blocker of the delayed rectifier K+ channel found in virtual screening.

14-Benzoyltalatisamine is a potent and selective blocker of the delayed rectifier K+ channel found in a computational virtual screening study. The compound was found to block the K+ channel from the extracellular side. However, it is unclear whether 14-benzoyltalatisamine shares the same block mechanism with tetraethylammonium (TEA).

Selective modulation of L-type calcium current by magnesium lithospermate B in guinea-pig ventricular myocytes.

Magnesium lithospermate B (MLB) is the main water-soluble principle of Salviae Miltiorrhizae Radix (also called as 'Danshen' in the traditional Chinese medicine) for the treatment of cardiovascular diseases. MLB was found to possess a variety of pharmacological actions. However, it is unclear whether and how MLB affects the cardiac ion channels.

Trans-resveratrol, a red wine ingredient, inhibits voltage-activated potassium currents in rat hippocampal neurons.

The red wine ingredient trans-resveratrol was found to exert potent neuroprotective effects in different in vivo and in vitro models. Thus far, the mechanisms underlying the neuroprotection were attributed mainly to its antioxidant properties. The aim of this study was to investigate the actions of trans-resveratrol on voltage-gated K(+) channels, which have been implicated in neuronal apoptosis.

Donepezil blocks voltage-gated ion channels in rat dissociated hippocampal neurons.

Donepezil (E2020) is a novel cholinesterase inhibitor for the treatment of Alzheimer's disease. Recent studies show that it may act on targets other than acetylcholinesterase in the brain. In the present study, the actions of donepezil on voltage-gated Na+ and K+ channels were investigated in rat dissociated hippocampal neurons.

Tetrahydroacridine inhibits voltage-dependent Na(+) current in guinea-pig ventricular myocytes.

Aim: To study the effects of tetrahydroacridine (tacrine) on voltage-gated Na(+) channels in cardiac tissues.

Methods: Single ventricular myocytes were enzymatically dissociated from adult guinea-pig heart. Voltage-dependent Na(+) current was recorded using whole cell voltage-clamp technique.

Purification and pharmacological characterization of BmKK2 (alpha-KTx 14.2), a novel potassium channel-blocking peptide, from the venom of Asian scorpion Buthus martensi Karsch.

BmKK2 (alpha-KTx 14.2) is one of the novel short-chain peptides found in molecular cloning of a venom gland cDNA library from Asian scorpion Buthus martensi Karsch. Based upon its amino acid sequence, the peptide was proposed to adopt a classical alpha/beta-scaffold for alpha-KTxs.

BmTx3B, a novel scorpion toxin from Buthus martensi Karsch, inhibits delayed rectifier potassium current in rat hippocampal neurons.

Aim: To examine the effect of BmTx3B, a novel short-chain peptide isolated from the venom of Asian scorpion Buthus martensi Karsch, on voltage-gated potassium channels.

Methods: Two types of voltage-dependent potassium currents were recorded from dissociated hippocampal neurons of neonatal rat in whole-cell voltage-clamp mode, and separated based upon their kinetic properties.

Results: BmTx3B (10-100 micromol/L) selectively inhibited the delayed rectifier potassium current (I(K)), without affecting the fast transient potassium current (I(A)).

BmKK4, a novel toxin from the venom of Asian scorpion Buthus martensi Karsch, inhibits potassium currents in rat hippocampal neurons in vitro.

A novel short-chain peptide BmKK4 was isolated from the venom of Asian scorpion Buthus martensi Karsch. It is composed of 30 amino acids including six cysteine residues, and shares less than 25% sequence identity with the known alpha-KTx toxins. The action of BmKK4 on voltage-dependent potassium currents was examined in acutely dissociated hippocampal neurons of rat.

Songorine, a diterpenoid alkaloid of the genus Aconitum, is a novel GABA(A) receptor antagonist in rat brain.

Songorine, a diterpenoid alkaloid isolated from the genus Aconitum, was recently found to enhance the excitatory synaptic transmission in rat hippocampus. The mechanism underlying the effects was examined in the present study. The alkaloid at 0.

Huperzine A inhibits the sustained potassium current in rat dissociated hippocampal neurons.

The actions of huperzine A (HupA), a novel cholinesterase inhibitor, on the sustained potassium current were investigated in acutely dissociated hippocampal neurons of rat. HupA inhibited the current (IC(50) = 856 +/- 1 microM) with voltage-dependency. The effect was insensitive to 3 microM atropine.