Uptake of monoamines by mesenteric mast cells of the mouse

The influence of catecholamines and serotonin on histamine uptake and metabolism by guinea pig atrium

The influence of serotonin and catecholamines on the uptake and metabolism of 14C-histamine by isolated guinea pig atrium has been investigated. Epinephrine, norepinephrine and serotonin were found to reduce the histamine uptake and the formation of methylhistamine, in a dose-dependent fashion. The order of potency was epinephrine greater than norepinephrine greater than serotonin. Aliphatic diamines, such as spermine, do not affect the accumulation and metabolism of histamine. It is suggested that serotonin and catecholamines, may enhance histamine responses by decreasing the uptake and metabolism of this amine.

Studies on the 14C-histamine release induced by noradrenaline in mouse neoplastic mast cells

Murine neoplastic mast cells incubated with labelled histamine released 14C-histamine when exposed to increasing concentrations of noradrenaline. This process was blocked by low temperature, by inhibiting oxidative metabolism and glycolysis, by calcium deprivation and by cytochalasin B. Electron microscope observations of cells exposed to noradrenaline revealed an increase of the Juxtanuclear Golgi Apparatus, and the appearance of a pronounced peripheral vacuolization. Cells exposed simultaneously to noradrenaline and cytochalasin B were characterized by a further increase of the Golgi apparatus, and by the appearance of many electron dense cytoplasmic granules. The possible mechanisms of the noradrenaline induced histamine release were discussed.