The modulation of histamine release by alpha-adrenoceptors: evidences in murine neoplastic mast cells.

Murine neoplastic mast cells which have been loaded with exogenous labelled histamine, released 14C-histamine when exposed to increasing concentrations of phenylephrine and noradrenaline. Adrenaline was only slightly effective, while isoprenaline and dibutyryl-cyclic-AMP were fully inactive. The release of histamine evoked by alpha-adrenergic agonists was antagonized by phentolamine, and left unchanged by practolol and cocaine. It is concluded that alpha-adrenoceptors may be valuable in evoking histamine release by murine neoplastic mast cells.