1217888-95-3Relevant articles and documents
Lobeline esters as novel ligands for neuronal nicotinic acetylcholine receptors and neurotransmitter transporters
Hojahmat, Marhaba,Horton, David B.,Norrholm, Seth D.,Miller, Dennis K.,Grinevich, Vladimir P.,Deaciuc, Agripina Gabriela,Dwoskin, Linda P.,Crooks, Peter A.
experimental part, p. 640 - 649 (2010/05/02)
Vesicular monoamine transporter-2 (VMAT2) is a viable target for development of pharmacotherapies for psychostimulant abuse. Lobeline (1) is a potent antagonist at α4β2* nicotinic acetylcholine receptors, has moderate affinity (Ki = 5.46 μM) for VMAT2, and is being investigated currently as a clinical candidate for treatment of psychostimulant abuse. A series of carboxylic acid and sulfonic acid ester analogs 2-20 of lobeline were synthesized and evaluated for interaction with α4β2* and α7* neuronal nicotinic acetylcholine receptors (nAChRs), the dopamine transporter (DAT), serotonin transporter (SERT) and VMAT2. Both carboxylic acid and sulfonic acid esters had low affinity at α7* nAChRs. Similar to lobeline (Ki = 4 nM), sulfonic acid esters had high affinity at α4β2* (Ki = 5-17 nM). Aromatic carboxylic acid ester analogs of lobeline (2-4) were 100-1000-fold less potent than lobeline at α4β2* nAChRs, whereas aliphatic carboxylic acid ester analogs were 10-100-fold less potent than lobeline at α4β2*. Two representative lobeline esters, the 10-O-benzoate (2) and the 10-O-benzenesulfonate (10) were evaluated in the 36Rb+ efflux assay using rat thalamic synaptosomes, and were shown to be antagonists with IC50 values of 0.85 μM and 1.60 μM, respectively. Both carboxylic and sulfonic acid esters exhibited a range of potencies (equipotent to 13-45-fold greater potency compared to lobeline) for inhibiting DAT and SERT, respectively, and like lobeline, had moderate affinity (Ki = 1.98-10.8 μM) for VMAT2. One of the more interesting analogs, p-methoxybenzoic acid ester 4, had low affinity at α4β2* nAChRs (Ki = 19.3 μM) and was equipotent with lobeline, at VMAT2 (Ki = 2.98 μM), exhibiting a 6.5-fold selectivity for VMAT2 over α4β2 nAChRs. Thus, esterification of the lobeline molecule may be a useful structural modification for the development of lobeline analogs with improved selectivity at VMAT2.
