Fig. 4

Effects of NRG-1β on intrafusal nuclear bag and chain fiber formation. a NRG-1β: a1 NF-200-IR neurons, a2 SKM cells, a3 DAPI, and a4 overlay of a1, a2, and a3. b NRG-1β + PD98059: b1 NF-200-IR neurons, b2 SKM cells, b3 DAPI, and b4 overlay of b1, b2, and b3. c NRG-1β + LY294002: c1 NF-200-IR neurons, c2 SKM cells, c3 DAPI, and c4 overlay of c1, c2, and c3. d NRG-1β + AG490: d1 NF-200-IR neurons, d2 SKM cells, d3 DAPI, and d4 overlay of d1, d2, and d3. e control: e1 NF-200-IR neurons, e2 SKM cells, e3 DAPI, and e4 overlay of e1, e2, and e3. Scale bar = 20 μm. 4-1 a–e Intrafusal nuclear bag fiber (red) with gathered nuclei (blue) inside and sensory nerve terminals wrapping around the bag fiber surface. 4-2 a–e Intrafusal nuclear chain fiber (red) with linear assembled nuclei (blue) inside and sensory nerve terminals wrapping around the chain fiber surface. 4-1 f Quantification of number of nuclear bag fibers. 4-2 f Quantification of number of nuclear chain fibers. Mean ± SD, n = 5. *P < 0.05, **P < 0.01, ***P < 0.001