Chemical kindling induced by pentylenetetrazol in histamine H(1) receptor gene knockout mice (H(1)KO), histidine decarboxylase-deficient mice (HDC(-/-)) and mast cell-deficient W/W(v) mice.

The role of brain histamine on seizure development of pentylenetetrazol (PTZ)-induced kindling was examined in H(1)-receptor gene knockout (H(1)KO), histidine decarboxylase-deficient (HDC(-/-)) and mast cell-deficient (W/W(v)) mice. All H(1)KO, HDC(-/-) and W/W(v) mice had accelerated seizure development of PTZ-induced kindling when compared to their respective wild-type mice. The daily PTZ-kindling increased histamine content in the cortex and diencephalon of H(1)KO mice, whereas the histamine content in the diencephalon of W/W(v) mice was decreased. The present study indicates that histamine plays a suppressive role in seizure development through H(1)-receptors.