CAPILLARY ELECTROPHORESIS OF SINGLE CELLS - OBSERVATION OF 2 COMPARTMENTS OF NEUROTRANSMITTER VESICLES

Capillary electrophoresis has been used to directly identify and measu re the neurotransmitter, dopamine, in two vesicular compartments in a single nerve cell of Planorbis corneus. Dopamine in the cytoplasm and in easily released transmitter vesicles was separated from dopamine in what are apparently non-functional storage vesicles. In this method, the two peaks in the electropherogram attributed to dopamine were diff erentiated based on cell lyse time in a non-physiorogical buffer. The measurements presented here suggest that of the total dopamine present in the cell: 24% is in the cytoplasmic and easily released compartmen ts and 76% is more centrally located, perhaps in a reserve compartment , in the cell. This methodology provides the means to determine molecu lar species in subcellular compartments and should allow kinetic param eters associated with membrane lysing to be evaluated at single nerve cells.