Quantitative correlation between histamine and 35S release from isolated rat mast cells due to the beta-adrenergic blocking drug Kö 1124.

An attempt was made to explain the mechanism of histamine release from isolated rat mast cells induced by the beta-adrenergic blocking drug Kö 1124. This drug at the highest concentration used released 12 times more histamine than most other investigated beta-blockers. The release of histamine with Kö 1124 was dose and temperature dependent. The maximal histamine release was at pH 8 and in the absence of calcium ions. Increased calcium concentration decreased histamine release significantly. The effect of Kö 1124 on histamine release from mast cells was inhibited only by cocaine and 2,4-dinitrophenol; other metabolic inhibitors were ineffective. The histamine release due to Kö 1124 was not followed by an equal release of 35S. Isoprenaline in equimolar concentration decreased histamine release induced by Kö 1124 significantly. The release of 35S-labelled granules was decreased or blocked by isoprenaline.