Immunohistochemical detection of vascular endothelial growth factor (VEGF)and VEGF-receptors Flt-1 and KDR/Flk-1 in the vestibule of guinea pigs

Vascular endothelial growth factor (VEGF), known as an endothelial cell-spe cific mitogen, has been reported to be linked also to the NO/cGMP-pathway, which has been notified in the inner ear. Up to now, VEGF has not yet been described in the inner ear. We performed immunohistochemical analysis using specific antibodies to VEGF and to both known VEGF-receptors Flt-1 and KDR /Flk-1 on paraffin-sections of temporal bones from guinea pigs (n = 5). Imm unoreactivity of VEGF, Flt-1 and KDR/Flk-1 was detectable in a subpopulatio n of vestibular ganglion cells. VEGF could be found also in the endothelium of blood vessels, in fibrocytes of the lamina propria and in the neuroepit helium. Strong immune-labelling to Flt-1 was evident in nerve fibres, vascu lar endothelium and in the neuroepithelium. Fibrocytes, endothelium of bloo d vessels, supporting cells and calyces in the sensory epithelium revealed immunoreactivity to KDR/Flk-1. These findings give evidence that VEGF, Flt- 1 end KDR/Flk-1 are constitutively expressed in the vestibule. (C) 2000 Els evier Science Ireland Ltd. All rights reserved.