Spontaneous histamine secretion during isolation of rat cardiac mast cells

Objektive: 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 I and 2. Percentages of histamine release from cell isolates following Protocol 1 were 40 +/- 5%, 41 +/- 6%, and 51 +/- 17% at 0, 30, and 300 ug/mL of compound 48/80. Conclusions: Enzymatic dispersion of cardiac mast cells affects their response to secretagogues.