Effects of morphine on histamine release from two cell lines of canine mast cell tumor and on plasma histamine concentrations in dogs with cutaneous mast cell tumor.

Objective: To determine the effects of morphine on histamine release from 2 canine mast cell tumor (MCT) cell lines and on plasma histamine concentrations in dogs with cutaneous MCTs.

Animals: 10 dogs with cutaneous MCT and 10 dogs with soft tissue sarcoma (STS).

Procedures: The study consisted of 2 phases.