Subcellular distribution of [3H]amphetamine and [3H]guanethidine and their interaction with adrenergic neurons

The subcellular distribution of ³H]amphetamine and ³H]guanethidine and their interaction with each other and with noradrenaline binding sites have been examined. The ratio p/(p + s) × 100, an indication of affinity for noradrenaline storage particles, for ³H]amphetamine and ³H]guanethidine was 12% and 57% respectively. Protriptyline, a substance which inhibits amine transport mechanism at the level of the cell membrane, i.e. the membrane pump, and reserpine, an agent which impairs incorporation of amines into the storage particles in the adrenergic nerve fibre, inhibited the uptake and storage respectively, of ³H]guanethidine more than that of ³H]amphetamine. Retention of ³H]guanethidine by rat salivary glands was markedly decreased by sympathetic denervation of the glands while that of ³H]amphetamine was not. The results suggest that guanethidine possesses a much higher affinity for noradrenaline binding sites than amphetamine.