Direct observation of 6-fluorodopamine in guinea pig nerve microsacs by 19F NMR

19F nuclear magnetic resonance (NMR) has been used to examine the disposition of ring-fluorinated dopamine and norepinephrine in microsacs prepared from striata of guinea pig brains. Following incubation with a 10(-4)M initial concentration of 6-fluorodopamine (6F-DA), intact micmicrosacs at 4 degrees C gave a 19F NMR spectrum in which the 6F-DA present was sufficiently mobile to be visible. Intra-vesicular 6F-DA in striatal nerve terminals thus appears to exist in an environment resembling that in chromaffin vesicles but different from that prevailing inside the amine storage vesicles of platelets. Our data also suggest that the study of fluorinated compounds by 19F NMR can be used to expand our understanding of processes related to amine uptake, metabolism, and storage in nerves.