Objective: To test the hypothesis that spontaneous release of histamine occurring during an isolation protocol may modify responses of rat cardiac mast cells (connective tissue-type mast cells) to secretagogues.
Methods: We assessed two protocols for enzymatic dispersion utilizing collagenase, hyaluronidase, and deoxyribonuclease; with protease (Protocol 1, n = 8) or without protease (Protocol 2, n = 3). Spontaneous release of histamine was quantified following mechanical and enzymatic dispersion of the whole heart.
Results: Total histamine loss (Mean +/- SEM) was 963+/-92 and 833+/-60 ng/g of tissue weight following Protocols 1 and 2. Percentages of histamine release from cell isolates following Protocol 1 were 40+/-5%, 41+/-6%, and 51+/-7% at 0, 30, and 300 microg/mL of compound 48/80.
Conclusions: Enzymatic dispersion of cardiac mast cells affects their response to secretagogues.