Fibroblast growth factor 7 is a nociceptive modulator secreted via large dense-core vesicles

sayid muhammad ridhwi;

Fibroblast growth factor (FGF) 7, a member of FGF family, is initially found to be secreted from mesenchymal cells to repair epithelial
tissues. However, its functions in the nervous system are largely unknown. The present study showed that FGF7 was a neuromodulator
localized in the large dense-core vesicles (LDCVs) in nociceptive neurons. FGF7 was mainly expressed in small-diameter neurons of the
dorsal root ganglion and could be transported to the dorsal spinal cord. Interestingly, FGF7 was mostly stored in LDCVs that did not
contain neuropeptide substance P. Electrophysiological recordings in the spinal cord slice showed that buffer-applied FGF7 increased
the amplitude of excitatory post-synaptic current evoked by stimulating the sensory afferent fibers. Behavior tests showed that intrathecally applied FGF7 potentiated the formalin-induced acute nociceptive response. Moreover, both acute and inflammatory nociceptive responses were significantly reduced in Fgf7-deficient mice. These results suggest that FGF7 exerts an excitatory modulation of nociceptive afferent transmission.