Cholinergics - aromatic amino acids and amines interactions a spectroscopic investigation

UV absorption spectroscopic methods were used for the studies of interaction between some cholinergic compounds; acetylcholine, acetyl- beta methylcholine, and carbacholine, with indolic compounds; L-tryptophan and tryptamine in order to elucidate the mechanism of action for these neurohumoral compounds at the molecular level. This was done through calculation of thermodynamic parameters [K, delta G°, delta H°, and delta S°] for 1:1 complex which is predominated. The K values were mostly less than one and were found to be temperature and wavelength dependent, which reflect the values of other thermodynamic parameters. A charge transfer [CT] complex formation between cholinergic compounds [electron- donors], and L- tryptophan and tryptamine [electron- acceptors] was concluded