Uptake of adrenaline by rat brain synaptosomes. Effects of several psychotropic drugs

: Comparative study of the uptake of 3H-epinephrine (3H-EN) and 3H-norepinephrine (3H-NE) into rat brain crude synaptosomes and effect of psychotropic drugs of different classes on this process showed that isolated nerve terminals had their own transport system for EN. The crude synaptosomal fraction had two transport system's for EN; high-specific active uptake with high affinity (KM = 3.7 + 0.21 microM) and low-affinity uptake (KM2 = 98.0 + 47.5 microM). En accumulation was saturable, stereo-specific and inhibited by ouabain (3 X 10(-3) M), protoveratrine A and B (10(-4) M), NaN3 (2 X 10(-3) M), 2,4-dinitrophenol (2 X 10(-3) M), p-chloromercuribenzoate (10(-4) M). Actinomycin D had no effect on the uptake of 3H-EN. 3H-HE was accumulated by two uptake system: 1-high affinity uptake system with KM values of 0.49 + 0.13 microM, 2-low affinity uptake system with KM values of 21.1 + 7.71 microM. Amphetamine, mesocarb, chlorpromazine, fluphenazine and haloperidol were equally effective inhibitors of 3H-EN and 2H-HE uptake. Imipramine, phenazepam, diazepam and carbamazepine (5 X 10(-5) M) had no effect on the uptake of 3H-NE. Imipramine, zimelidine, norzimelidine and viloxazine (5 X 10(-5) M) were more potent inhibitors of the 3H-EN uptake than that of 3H-NE.