Effects of histamine and its receptor antagonists on peritoneal permeability.

Peritoneal fluid and mass transfer rates were studied in rabbits undergoing control dialyses and dialyses with intraperitoneal histamine, or its receptor antagonists alone or in combination. These drugs had negligible effects on peritoneal ultrafiltration and small solute clearances. Histamine raised protein exudation from 1.6 to 2.9 mg/kg/min, an effect blocked by its antagonists which given alone did not lower protein loss. These data demonstrate the existence of histamine receptors in the peritoneal diffusion barrier and show that they do not control transport under baseline conditions, but can be blocked should abnormal histamine release occur. Increased peritoneal permeability with sterile peritonitis was unaffected by ranitidine, suggesting alternative mediators.