(±)-Vesamicol hydrochloride

N-hydroxyalkyl derivatives of 3 beta-phenyltropane and 1-methylspiro[1H-indoline-3,4'-piperidine]: vesamicol analogues with affinity for monoamine transporters.[Pubmed:9397171]

J Med Chem. 1997 Nov 21;40(24):3905-14.

As part of our ongoing structure-activity studies of the vesicular acetylcholine transporter ligand 2-(4-phenylpiperidino)cyclohexanol (vesamicol, 1), 22 N-hydroxy(phenyl)alkyl derivatives of 3 beta-phenyltropane, 6, and 1-methylspiro[1H-indoline-3,4'-piperidine], 7, were synthesized and tested for binding in vitro. Although a few compounds displayed moderately high affinity for the vesicular acetylcholine transporter, no compound was more potent than the prototypical vesicular acetylcholine transporter ligand vesamicol. However, a few derivatives of 6 displayed higher affinity for the dopamine transporter than cocaine. We conclude that modification of the piperidyl fragment of 1 will not lead to more potent vesicular acetylcholine transporter ligands.

Effects of systemic administration of 2-(4-phenyl-piperidino)-cyclohexanol (vesamicol) and an organophosphate DDVP on the cholinergic system in brain regions of rats.[Pubmed:9205789]

Brain Res Bull. 1997;43(1):17-23.

Vesamicol is known to inhibit the transport of acetylcholine (ACh) into synaptic vesicles in vitro, but much less is known about its effects in the brain in vivo. To assess the effect of vesamicol in vivo, we examined cholinergic parameters, such as the subcellular distribution of ACh, activities of enzymes, uptake of choline, and muscarinic receptor binding in the striatum, hippocampus, and cerebral cortex of rats 30 and 60 min after intraperitoneal injection of vesamicol (3 mg/kg) or of vesamicol in combination with DDVP (5 mg/kg), which was administered 10 min before vasamicol. The levels of cytosolic ACh increased in all regions of the brain after injection of vesamicol, while those of vesicular ACh decreased in all regions except for the striatum. The increase in the levels of extracellular ACh and cytosolic ACh in the striatum induced by DDVP was generally enhanced after injection of vesamicol, Vesamicol did not reduce the level of vesicular ACh when DDVP had been injected previously. Vesamicol did not induce any significant changes in the activities of enzymes, choline uptake, or binding of [6H]quinuclidinyl benzilate to the muscarinic ACh receptors in the three regions. Changes in the cholinergic parameters caused by DDVP were not reversed by the combined administration of DDVP with vesamicol. The present results indicate that vesamicol can inhibit the transport of ACh into synaptic vesicles in the brain tissue in vivo, although it cannot reverse the effects of DDVP that has been injected prior to vesamicol.

Active transport of acetylcholine by the human vesicular acetylcholine transporter.[Pubmed:8910293]

J Biol Chem. 1996 Nov 1;271(44):27229-32.

The characteristics of ATP-dependent transport of acetylcholine (ACh) in homogenates of pheochromocytoma (PC-12) cells stably transfected with the human vesicular acetylcholine transporter (VAChT) cDNA are described. The human VAChT protein was abundantly expressed in this line and appeared as a diffuse band with a molecular mass of approximately 75 kDa on Western blots. Vesicular [3H]ACh accumulation increased approximately 20 times over levels attained by the endogenous rat VAChT, expressed at low levels in control PC-12 cells. The transport of [3H]ACh by human VAChT was dependent upon the addition of exogenous ATP at 37 degrees C. Uptake was abolished by low temperature (4 degrees C), the proton ionophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (2.5 microM) and bafilomycin A1 (1 microM), a specific inhibitor of the vesicular H+-ATPase. The kinetics of [3H]ACh uptake by human VAChT were saturable, exhibiting an apparent Km of 0.97 +/- 0.1 mM and Vmax of 0.58 +/- 0.04 nmol/min/mg. Maximal steady-state levels of vesicular [3H]ACh accumulation were directly proportional to the concentration of substrate present in the medium with saturation occurring at approximately 4 mM. Uptake was stereospecifically inhibited by L-vesamicol with an IC50 of 14.7 +/- 1.5 nM. The apparent affinity (Kd) of [3H]vesamicol for human VAChT was 4.1 +/- 0.5 nM, and the Bmax was 8.9 +/- 0.6 pmol/mg. The turnover (Vmax/Bmax) of the human VAChT was approximately 65/min. This expression system should prove useful for the structure/function analysis of VAChT.