Disease relevance of (+)-Vesamicol

• The vesicular acetylcholine transporter (VAChT) has been identified and characterized based on the acquisition of high affinity vesamicol binding and proton-dependent, vesamicol-sensitive acetylcholine accumulation by a fibroblast cell line transfected with a clone from a rat pheochromocytoma cDNA library encoding this protein [1].
• 5. Both the tonic contracture and the prolonged depolarization were highly sensitive to blockade by tubocurarine (IC50 0.05-0.1 microM) and vesamicol (1 microM, an inhibitor of packaging acetylcholine into synaptic vesicles), were attenuated by increasing Ca2+ concentration and were prolonged by decreasing Ca2+ [2].
• To diagnose and investigate neurodegenerative diseases affecting cholinergic neuron density, piperazine derivatives of vesamicol were synthesized and evaluated [3].

Psychiatry related information on (+)-Vesamicol

• Results obtained in experiment 1 showed a dose-response reduction of REM sleep with significant values at 80 micrograms and 100 micrograms of vesamicol [4].
• Choline acetyltransferase activity and vesamicol binding in Rett syndrome and in rats with nucleus basalis lesions [5].
• Beta-amyloid protein-infused rats with spatial memory impairment may be useful for the development of new radiolabelled vesamicol analogues for the objective evaluation of Alzheimer's disease [6].

High impact information on (+)-Vesamicol

• Phosphorylation of serine 480 was attributable to the action of protein kinase C. Using a permanently dephosphorylated form of rat VAChT, S480A rVAChT, it was shown that this mutant displays the same kinetics for the transport of acetylcholine and the binding of the inhibitor vesamicol as does the wild type transporter [7].
• These data suggest that Asp-398 in TM10 and Asp-425 in TM11 are important for ACh binding and transport, while Asp-193 and Asp-398 in TM4 and TM10, respectively, are involved in vesamicol binding [8].
• By reciprocal kinetic experiments with vesamicol and ABV, coincidence of the two binding sites on vesicles was established [9].
• Fractional vesamicol receptor occupancy and acetylcholine active transport inhibition in synaptic vesicles [10].
• Vesamicol [(-)-(trans)-2-(4-phenylpiperidino)cyclohexanol] receptor binding and inhibition of acetylcholine (AcCh) active transport by cholinergic synaptic vesicles that were isolated from Torpedo electric organ were studied for 23 vesamicol enantiomers, analogues, and other drugs [10].

Biological context of (+)-Vesamicol

• It is concluded that many drugs can bind to the vesamicol receptor and binding to only a small fraction of the receptors can result in AcCh active transport inhibition [10].
• Use of trace [3H]vesamicol and [14C]AcCh allowed simultaneous determination of the concentrations of enantiomer, analogue, or drug required to half-saturate the vesamicol receptor (Ki) and to half-inhibit transport (IC50), respectively [10].
• We suggest that PKC alters the output of [3H]ACh formed in the presence of vesamicol and also provide circumstantial evidence for a role of phosphorylation of VAChT in this process [11].
• These results suggest that ouabain releases a vesamicol-insensitive pool of ACh from the sympathetic ganglion and also support the notion that this compartment is vesicular and its exocytosis depends on extracellular Ca2+ [12].
• The data demonstrate that the vesamicol family of compounds binds to an allosteric site in the AcChT [13].

Anatomical context of (+)-Vesamicol

• The lead-induced release of [3H]ACh was blocked by treatment of synaptosomes with vesamicol, which prevents uptake of ACh into synaptic vesicles without affecting its synthesis in the synaptoplasm [14].
• Initial studies presented in this article demonstrate the existence of a specific, saturable vesamicol binding site in PC12 cells [15].
• Moreover, this effect of vesamicol was (a) concentration-dependent and saturable (EC50 = 68 nM), (b) rapidly reversible, (c) stereospecific for the L-isomer, and (d) poorly mimicked by a vesamicol analog with lower plasma membrane permeability [16].
• In the presence of Ca2+, coincident with the release of the vesamicol-insensitive pool of ACh, nerve terminals were almost depleted of synaptic vesicles; ganglia treated similarly, but with medium containing 18 mM Mg2+ instead of Ca2+, were not depleted of synaptic vesicles [12].
• The properties of the receptor for vesamicol were studied by measuring binding of [3H]vesamicol, and the amount of SV2 antigen characteristic of secretory vesicles was assayed with a monoclonal antibody directed against it [17].

Associations of (+)-Vesamicol with other chemical compounds

• A protein that binds vesamicol has been purified from a soluble fraction of the Torpedo electric organ homogenate that does not contain synaptic vesicles [18].
• The present experiments measured the release and the synthesis of acetylcholine (ACh) by cat sympathetic ganglia in the presence of 2-(4-phenylpiperidino)cyclohexanol (AH5183 or vesamicol) and/or picrylsulfonic acid (TNBS), two compounds known to have the ability to block the uptake of ACh by cholinergic synaptic vesicles in vitro [19].
• The principal inhibitors were (-)-vesamicol (VES), hemicholinium-3 (HC3), and NH4+ [20].
• 7. Vesamicol is an inhibitor of active ACh uptake into isolated synaptic vesicles [21].
• Effect of N,N'-dicyclohexylcarbodiimide on the binding of vesamicol, an inhibitor of acetylcholine transport into synaptic vesicles [22].

Gene context of (+)-Vesamicol

• Levels of the VAChT were reduced by a range of 13-31% on PND 3 through 30 in the high-dosage group, using 3H-AH5183 (vesamicol) as the ligand [23].
• Treatment of slices with the PKC activator phorbol myristate acetate (PMA) decreased the inhibitory effect of vesamicol on [3H]ACh release [11].
• Recovery was blocked by (-)-vesamicol (VES), by hemicholinium-3 (HC3) and by nicotinic cholinergic agonists - all of which inhibit ACh loading into synaptic vesicles [24].
• At 23 degrees C, [3H]vesamicol bound to the receptor at a rate of (1.74 +/- 0.06) x 10(5) M-1 s-1, and excess unlabeled vesamicol displaced a low concentration of bound [3H]vesamicol at 0.29 +/- 0.01 min-1 [25].
• In particular, vesamicol binding compartments have a lower density than catecholaminergic vesicles and, unlike these latter vesicles, do not appear to contain the vesicle-specific proteins synaptophysin and SV2 as part of the same membrane [15].

Analytical, diagnostic and therapeutic context of (+)-Vesamicol

• The observed difference between the equilibrium dissociation constant for the vesamicol-VR complex as estimated by titration with [3H]vesamicol (7.6 nM) and by displacement of subsaturating [3H]vesamicol by nonlabeled vesamicol (1.0 nM) suggests that high and low affinity populations of the VR exist [9].
• A similar inhibitory effect was produced by direct intrastriatal perfusion with vesamicol [16].
• Vesamicol inhibited [14C]ACh release evoked by both veratridine and electrical stimulation in the presence of external Ca2+, provided it was added to the tissue prior to loading with [14C]choline [26].
• 4. Further studies with the active isomer, (-)-vesamicol, showed that, like that produced by racemic vesamicol, the neuromuscular block was highly frequency-dependent [27].
• Direct optical resolution of vesamicol and a series of benzovesamicol analogues by high-performance liquid chromatography [28].

References