Mast cells are important effector cells of the immune system. We describe a
rapid and inexpensive microassay to determine histamine release from human
gingival mast cells. The assay is based on the coupling of histamine with
o-phthalaldehyde (OPT) at a highly alkaline pH to form a fluorescent produc
t. Using this assay with a sample volume of 10 mul/well in a 384 black well
microplate, the histamine detection limit was 0.031 mug/ml. The human mast
cell line (HMC-1) and fresh mast cells isolated from human gingival tissue
(n = 10) were stimulated with substance P, anti-IgE or calcium ionophore A
23187, Calcium ionophore significantly increased histamine release from HMC
-1 cells and gingival mast cells (p < 0.05). This microassay will facilitat
e the study of mast cell histamine release in diseased oral mucosa.