Recognition properties and competitive assays of a dual dopamine/serotonin selective molecularly imprinted polymer.
A molecularly imprinted polymer (MIP) with dual dopamine/serotonin-like binding sites (DS-MIP) was synthesized for use as a receptor model of study the drug-interaction of biological mixed receptors at a molecular level. The polymer material was produced using methacrylic acid (MAA) and acrylamide (ACM) as functional monomers, N,N'-methylene bisacrylamide (MBAA) as cross-linker, methanol/water mixture (4:1, v/v) as porogen and a mixture of dopamine (D) and serotonin (S) as templates. The prepared DS-MIP exhibited the greatest rebinding of the template(s) in aqueous methanol solution with decreased recognition in acetonitrile, water and methanol solvent. The binding affinity and binding capacity of DS-MIP with S were found to be higher than those of DS-MIP with D. The selectivity profiles of DS-MIP suggest that the D binding site of DS-MIP has sufficient integrity to discriminate between species of non-optimal functional group orientation, whilst the S binding site of DS-MIP is less selective toward species having structural features and functional group orientations different from S. The ligand binding activities of a series of ergot derivatives (ergocryptine, ergocornine, ergocristine, ergonovine, agroclavine, pergolide and terguride) have been studied with the DS-MIP using a competitive ligand binding assay protocol. The binding affinities of DS-MIP were demonstrated in the micro- or submicro-molar range for a series of ergot derivatives, whereas the binding affinities were considerably greater to natural receptors derived from the rat hypothalamus. The DS-MIP afforded the same pattern of differentiation as the natural receptors, i.e. affinity for the clavines > lysergic acid derivatives > ergopeptines. The results suggest that the discrimination for the ergot derivatives by the dopamine and serotonin sites of DS-MIP is due to the structural features and functional orientation of the phenylethylamine and indolylethylamine entities at the binding sites, and the fidelity of the dopamine and serotonin imprinted cavities.
Suedee
Roongnapa
R
Molecular Recognition Materials Research Unit, Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hatyai, Songkla 90112, Thailand.
Seechamnanturakit
Vatcharee
V
Molecular Recognition Materials Research Unit, Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hatyai, Songkla 90112, Thailand.
Suksuwan
Acharee
A
Molecular Recognition Materials Research Unit, Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hatyai, Songkla 90112, Thailand.
Canyuk
Bhutorn
B
Molecular Recognition Materials Research Unit, Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hatyai, Songkla 90112, Thailand.