The contribution of mast cells to the histamine content of the central nervous system: a regional analysis.

W/WV mice are severely deficient in mast cells. The absence of mast cells in skin and salivary glands was found to be paralleled by a drastic decrease of the histamine levels in these tissues when compared to non-anemic +/+ control mice. Brains of W/WV mice are also devoid of mast cells. A comparison of the histamine concentrations in several brain regions of W/WV mice and controls revealed a moderate decrease in cerebral cortex, thalamus, hypothalamus and midbrain but no change in pons, medulla and cerebellum. These findings provide strong evidence that mast cells contribute to the histamine content in forebrain regions but not in hindbrain regions. It is speculated that there may exist histaminergic neurons intrinsic to the medulla and pons.