Experimental renal anaphylaxis: release of histamine and study of its effect on renal perfusion.

Antigen challenge of isolated perfused kidneys of sensitized guinea-pigs consistently released a large proportion of their histamine content, and caused a reduction in renal perfusate flow rate (RPFR) which could not simply be due to the released histamine, since much larger amounts of exogenous histamine were needed to produce a comparable effect. Reduction in RPFR by histamine was blocked by mepyramine but not by cimetidine, i.e. it is mediated by an H1-receptor mechanism.