Overexpression of neurotrophin-3 enhances the mechanical response properties of slowly adapting type 1 afferents and myelinated nociceptors.

摘要: Constitutive overexpression of neurotrophin-3 (NT3) in murine skin results an increased number sensory neurons within the dorsal root ganglia, increase myelinated axons cutaneous nerves, hyperinnervation skin, and Merkel cells found flank skin. Here we used a saphenous skin/nerve preparation to determine if these anatomical changes affect functional response characteristics neurons. Overexpression NT3 significantly responses slowly adapting type 1 (SA1) low-threshold mechanoreceptors Aδ high-threshold suprathreshold mechanical stimulation. It also resulted faster conduction velocities SA1 fibers. In contrast earlier findings no differences were noted numbers touch domes hindlimb NT3-overexpressing mice. addition, dermal cells, located around hair follicles on dorsum foot, was reduced by 55%. The sensitivity correlate with significant increases expression acid-sensing ion channels (ASIC) 3. Additional experiments using intracellular recordings staining procedures confirmed that at least some nociceptors stained positively for both trkC ASIC3. These indicate alters properties specific neurons, may be due modulation putative mechanosensitive channels.