Uptake of norepinephrine by the isolated hypothalamic vesicles

Abstract

Norepinehrine storing vesicles were isolated from the hypothalamus of the pig and incubated at 37° and 0°C in the presence of Tris buffer or histidine buffer (pH 7.4). At 37°C the hypothalamic vesicles take up norepinephrine. The uptake is done is dose dependent and can be increased by ATP-Mg⁺⁺ or ATP-Ca⁺⁺. At 0°C only the uptake in the absence of ATP-Mg⁺⁺ takes place. The ATP-Mg⁺⁺ dependent uptake is more pronounced in the presence of histidine buffer than in Tris buffer. Isolated liver microsomes also take up catecholamines but the uptake is very slight and can not be further increased by ATP-Mg⁺⁺. It is concluded that the amine storing vesicles of the brain take up catecholamines by a passive and an active transport mechanism and further that the protein of these particles possesses a high affinity to norepinephrine.