Multiple sites of histamine storage in superior cervical ganglia

Histamine and mast cells are present in substantial quantities in superior cervical ganglia (SCG) in a variety of animals. In this study, SCG from mast cell-deficient W/Wv mice, from cogenic +/+ wild-type, and from Wistar control mice were examined for their endogenous histamine content and mast cell numbers. Measurements of SCG extracts with a micro-radioenzymatic histamine assay revealed that +/+ and Wistar ganglia contained about 20 pmol histamine per ganglion or 0.6 nmol/mg protein. Light microscopic inspection with toluidine blue staining of 6-micron sections prepared from +/+ and from Wistar SCG showed the presence of about 85 mast cells in each species. By contrast, no mast cell was observed in serial-sectioned SCG from W/Wv mice; despite the absence of stainable mast cells, their SCG consistently contained endogenous histamine, on average, 2 pmol per ganglion. These results are interpreted as evidence for the existence of a nonmast cell histamine compartment in sympathetic ganglia.