Specific inhibition of acetylcholinesterase as an approach to decrease muscarinic side effects during myasthenia gravis treatment.

Non-selective inhibitors of cholinesterases (ChEs) are clinically used for treatment of myasthenia gravis (MG). While being generally safe, they cause numerous adverse effects including induction of hyperactivity of urinary bladder and intestines affecting quality of patients life. In this study we have compared two ChEs inhibitors, a newly synthesized compound C547 and clinically used pyridostigmine bromide, by their efficiency to reduce muscle weakness symptoms and ability to activate contractions of urinary bladder in a rat model of autoimmune MG.

Phenylarsine oxide as a redox modulator of transient receptor potential vanilloid type 1 channel function.

Transient receptor potential vanilloid type 1 (TRPV1) channels are capable of detecting and integrating noxious stimuli and play an important role in nociceptor activation and sensitization. It has been demonstrated that oxidizing agents are capable of positively modulating (sensitizing) the TRPV1 channel. The present study investigates the ability of the thiol-oxidizing agent phenylarsine oxide (PAO) to modulate TRPV1 currents under voltage-clamp conditions.

Studies examining the relationship between the chemical structure of protoxin II and its activity on voltage gated sodium channels.

The aqueous solution structure of protoxin II (ProTx II) indicated that the toxin comprises a well-defined inhibitor cystine knot (ICK) backbone region and a flexible C-terminal tail region, similar to previously described NaSpTx III tarantula toxins. In the present study we sought to explore the structure-activity relationship of the two regions of the ProTx II molecule. As a first step, chimeric toxins of ProTx II and PaTx I were synthesized and their biological activities on Nav1.

Cysteine racemization during the Fmoc solid phase peptide synthesis of the Nav1.7-selective peptide--protoxin II.

Protoxin II is biologically active peptide containing the inhibitory cystine knot motif. A synthetic version of the toxin was generated with standard Fmoc solid phase peptide synthesis. If N-methylmorpholine was used as a base during synthesis of the linear protoxin II, it was found that a significant amount of racemization (approximately 50%) was observed during the process of cysteine residue coupling.

Pharmacological characterization of recombinant N-type calcium channel (Cav2.2) mediated calcium mobilization using FLIPR.

The N-type voltage-gated calcium channel (Ca(v)2.2) functions in neurons to regulate neurotransmitter release. It comprises a clinically relevant target for chronic pain.

Pharmacology of 2-[4-(4-chloro-2-fluorophenoxy)phenyl]-pyrimidine-4-carboxamide: a potent, broad-spectrum state-dependent sodium channel blocker for treating pain states.

Voltage-gated Na(+) channels may play important roles in establishing pathological neuronal hyperexcitability associated with chronic pain in humans. Na(+) channel blockers, such as carbamazepine (CBZ) and lamotrigine (LTG), are efficacious in treating neuropathic pain; however, their therapeutic utility is compromised by central nervous system side effects. We reasoned that it may be possible to gain superior control over pain states and, in particular, a better therapeutic index, by designing broad-spectrum Na(+) channel blockers with higher potency, faster onset kinetics, and greater levels of state dependence than existing drugs.

State-dependent compound inhibition of Nav1.2 sodium channels using the FLIPR Vm dye: on-target and off-target effects of diverse pharmacological agents.

Voltage-gated sodium channels (NaChs) are relevant targets for pain, epilepsy, and a variety of neurological and cardiac disorders. Traditionally, it has been difficult to develop structure-activity relationships for NaCh inhibitors due to rapid channel kinetics and state-dependent compound interactions. Membrane potential (Vm) dyes in conjunction with a high-throughput fluorescence imaging plate reader (FLIPR) offer a satisfactory 1st-tier solution.

Validation of a fluorescent imaging plate reader membrane potential assay for high-throughput screening of glycine transporter modulators.

A fluorescent imaging plate reader (FLIPR) membrane potential (V(m)) assay was evaluated for pharmacological characterization and high-throughput screening (HTS) of rat glycine transporter type 2 (rGlyT(2)) in a stable rGlyT(2)-HEK cell line. Data show that glycine activation of rGlyT(2) consistently results in a concentration-dependent V(m) response on the FLIPR that is blocked by the potent and selective GlyT(2) antagonist 4-benzyloxy-3,5-dimethoxy-N-[1-dimethylamino-cyclopentyl)methyl]-benz-amide (Org-25543). Agonist and antagonist pharmacologies match those reported using conventional [(3)H]glycine uptake assays and electrophysiology.

V102862 (Co 102862): a potent, broad-spectrum state-dependent blocker of mammalian voltage-gated sodium channels.

1. 4-(4-Fluorophenoxy)benzaldehyde semicarbazone (V102862) was initially described as an orally active anticonvulsant with robust activity in a variety of rodent models of epilepsy. The mechanism of action was not known.

A-317491, a selective P2X3/P2X2/3 receptor antagonist, reverses inflammatory mechanical hyperalgesia through action at peripheral receptors in rats.

The effect of A-317491 (5-([(3-Phenoxybenzyl)[(1S)-1,2,3,4-tetrahydro-1-naphthalenyl]amino]carbonyl)-1,2,4-benzenetricarboxylic acid), a recently described selective P2X3 and P2X(2/3) receptor antagonist, on inflammatory mechanical hyperalgesia was examined. In the rat Freund's complete adjuvant model of inflammatory pain, s.c.

Phenoxyphenyl pyridines as novel state-dependent, high-potency sodium channel inhibitors.

In the search for more efficacious drugs to treat neuropathic pain states, a series of phenoxyphenyl pyridines was designed based on 4-(4-flurophenoxy)benzaldehyde semicarbazone. Through variation of the substituents on the pyridine ring, several potent state-dependent sodium channel inhibitors were identified. From these compounds, 23 dose dependently reversed tactile allodynia in the Chung model of neuropathic pain.

3-(4-phenoxyphenyl)pyrazoles: a novel class of sodium channel blockers.

A series of 3-(4-phenoxyphenyl)-1H-pyrazoles were synthesized and characterized as potent state-dependent sodium channel blockers. A limited SAR study was carried out to delineate the chemical requirements for potency. The results indicate that the distal phenyl group is critical for activity but will tolerate lipophilic (+pi) electronegative (+sigma) substituents at the ortho and/or para position.

Shear stress regulates the endothelial Kir2.1 ion channel.

Endothelial cells (ECs) line the mammalian vascular system and respond to the hemodynamic stimulus of fluid shear stress, the frictional force produced by blood flow. When ECs are exposed to shear stress, one of the fastest responses is an increase of K(+) conductance, which suggests that ion channels are involved in the early shear stress response. Here we show that an applied shear stress induces a K(+) ion current in cells expressing the endothelial Kir2.