H3 receptor renal expression in normal and diabetic rats.

INTRODUCTION: To extend our previous observation of H4R upregulation in the kidney of diabetic rats, we evaluated in the same specimens the presence of the H3R. MATERIALS AND METHODS: Kidney specimens from 24 8-week-old male Wistar rats (12 non-diabetic and 12 diabetic animals) were processed for both immunohistochemical and immunofluorescence analyses. RESULTS AND CONCLUSION: H3R is expressed in the apical membrane by collecting duct cells in the kidney of rats and it is significantly increased in diabetic animals. These data support the hypothesis that H3R could also mediate non-neuronal histamine effects, suggesting its involvement in fluid homeostasis.