[Inhibition of 3-H-noradrenalin uptake in synaptosomes by substance P]

The uptake kinetics of DL-[3H]-norepinephrine into synaptosomes from rat brain hypothalamus can be described as a two stage process with uptake constants of Km = 0.9 micron and Km = 0.06 micron, respectively. Substance P exerts an inhibiting influence on both uptakes. The possible importance of this inhibition for the regulation of noradrenergic transmission is discussed.