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

Abstract

BLOOM, G. D., B. FREDHOLM and 0. HAEGERMARK. Studies on the time course nj'histarnine release and morphological changes induced by histamine liberators in rat peritoneal mast cells. Acta physiol. scand. 1967. 71. 270-282.The histamine release process in rat peritoneal mast cells, exposed to histamine liberators. can be terminated by the addition of ice-cold salt solution. This was taken advantage 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" C and about 30 sec at 22" C , independently of the liberator concentration. At 22-C the release was preceded by a lag period, which was shortcr with higher liberator concentrations. The enzyme inhibitors potassium 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 ndecylamine. The morphological changes, studied both in the light and electron microscopr, were found to be corrclatcd to the histamine releasc.

Arrest of membrane fusion events in mast cells by quick-freezing.

“…Early in the secretory process, single granules fuse with the plasma membrane, whereas at later stages membranes of adjacent granules in the cell interior fuse in succession to produce deep invaginations in the cell surface (1,19,28). These morphological observations correlate well with chemical measurements of release showing that 40-80% of the total cell histamine is secreted within 2 min (3,28). There is good evidence that secretion is initiated by a rise in intracellular calcium activity (9,10,16,17,22), and for this reason the mast cell represents an important model of calcium-mediated stimulus-secretion coupling (8,12).…”

“…Cells and filter paper were then dipped into PBS containing 4 or 8 pg/ml of the synthetic polycation 48/80 (Sigma Chemical Co., St. Louis, Mo. ), a well-known histaminereleasing agent (3,15,16,28). The sample was quick-frozen on the machine designed by Heuser et al .…”

“…Ultrastructural studies have shown that histamine secretion by mast cells, in response to either antigens or synthetic polycations, is mediated by a rapid, compound exocytosis (I, 3,15,16,18,19,28). Early in the secretory process, single granules fuse with the plasma membrane, whereas at later stages membranes of adjacent granules in the cell interior fuse in succession to produce deep invaginations in the cell surface (1,19,28).…”

Secretion of the Content of Granules and Its Relationship to the Acid Phosphatase Reaction in Regenerating Rat Peritoneal Mast Cells

“…The intracellular structures of mast cells such as nucleus, mitochondria, Golgi apparatus, were similar to those that have been described by many authors (1,2,3,6,7,8).…”

Mechanism of Histamine Release by Alpha-Chymotrypsin from Isolated Rat Mast Cells

“…The second point was a question whether or not histamine-releasing action of CT could be separated into 2 steps: releaser dependent, not Ca"-dependent, and Ca "-dependent, not releaser-dependent, as has been reported in IgE-mediated histamine release from human basophils (5-7). It has been suggested that the presence of compound 48/80 is not required for the histamine re lease from rat mast cells, once the activation of the cells is accomplished (8)(9)(10)(11). If such is indeed the case, properties of CT-activated mast cells are also worthy of delineation.…”