Studies on the Time Course of Histamine Release and Morphological Changes Induced by Histamine Liberators in Rat Peritoneal Mast Cells

The histamine release process in rat peritoneal mast cells, exposed to histomine liberators, can be terminated by the addition of ice‐cold salt solution. This was taken advantages of for studies on the time course of histamine release and concomitant morphological changes induced by compound 48/80, bee venom and n ‐decylamine. After addition of compound 48/80 or bee venom, histamine was released in about 10 sec at 37/dG C and about 30 sec at 22/dG C. independently of the liberator concentration. AT 22/dG C the release was preceded by a lag period, which was shorter with higher liberator concentrations. The enzyme inhibitors potssium cyanide and N‐ethylmaleimide did not alter the duration of the reaction induced by compound 48/80 or bee venom, although they lowered the final release. The release curve showed a different shape when histamine was released by n ‐decylamine. The morphological changes, studied both in the light and electron microscope, were found to be correlated to the histamine release.