Analysis of chemical processes at single bovine adrenergic chromaffin cells with micellar electrokinetic capillary chromatography and electrochemical detection

Micellar electrokinetic capillary chromatography with electrochemical detection (MEKC-EC) has been applied to the investigation of single cell systems. Separations of bovine adrenergic chromaffin cells reveal average contents of 33 ± 14 fmol of norepinephrine and 24 ± 11 fmol of epinephrine. The resolution benefits of MEKC-EC have been more fully realized in the analysis of a complex mixture resulting when adrenal cells are incubated with the dopamine precursor, L-dihydroxyphenylalanine (L-DOPA). Dopamine has been unambiguously identified in these cells, supporting the hypothesis that transport of dopamine into vesicles is a slow, rate-limiting process. In addition, MEKC-EC has been used to monitor the release of catecholamines from single adrenal cells when stimulated by nicotine. Low-fmol quantities of norepinephrine and epinephrine have been detected in the extracellular environment following stimulation.