Precise GC/MS assays for salsolinol and tetrahydropapaveroline: the question of artifacts and dietary sources and the influence of alcohol.

The use of GC/MS with appropriate deuterated internal standards has enabled the development of highly precise assays for salsolinol and THP. The deuterated standards we have prepared for the present assays are entirely free of contamination by non-deuterated species. The extraction and analytical techniques used in these studies do not lead to artifactual formation of either salsolinol or THP due to dopamine cyclization since neither alkaloid was detected in a variety of samples that contained high concentrations of dopamine. Examples are tomato, certain urine samples, rat brain samples including hypothalami from animals treated with pharmacological doses of l-dopa. While we have found little analytical support, at least in urine, for significant in vivo formation of salsolinol from endogenous dopamine and acetaldehyde, there is clear evidence that dietary sources of salsolinol contribute to its detection in biological samples. Whatever the origin of alkaloids such as salsolinol and THP in mammalian samples, their potential for affecting behavioural and physiological systems merit their continued study.