Veien et al.  used human cutaneous mast cells isolated from neonate foreskins to investigate the mechanisms of mediator release toward the further understanding of anaphylactoid reactions and other states of mast cell activation. Skin tissue was used within 24 h of circumcision, after incubation in CMF-HBSS with collagenase, hyaluronidase, and deoxyribonuclease.

Dispersed mast cell suspensions were challenged with vancomycin, calcium ionophore A23187, morphine, and atracurium, using concentrations based on in vitro  data and data applied to clinically relevant doses. To determine whether mast cell degranulation was calcium-dependent, cells were incubated in either a buffer containing 2.8 mM Ca2+and 1.0 mM Mg2+, or buffer from which Ca2+and Mg2+had been omitted. After three cycles of freezing and thawing to arrest the release reaction, the net histamine–tryptase release was calculated as a percent of total histamine release.

Vancomycin, calcium ionophore A23187, morphine, and atracurium, all known nonimmunologic stimulators, produced significant histamine and tryptase release in mast cells incubated in buffer containing calcium and magnesium. When calcium or magnesium was omitted from the incubation buffer, histamine release was decreased by 90% for vancomycin and almost abolished for morphine. However, calcium had no effect on the mast cell release reactions to A23187 or atracurium stimulation. Preincubation of the dispersed mast cells with the secretory PLA2 inhibitor OBAA attenuated vancomycin-induced histamine release from 19.4 ± 8.5% to 9.3 ± 6.3%, whereas the A23187-induced histamine release was not affected by the preincubation. Similarly, a PLC inhibitor also abolished the vancomycin-induced histamine release, but not the calcium ionophore A23187-induced histamine release. Because tryptase is released, along with histamine during nonimmunologic mast cell activation, it may not be a specific marker for anaphylaxis.