Figure 1.

lPBN lesions affect sustained pain

A: Schematic of lPBN bilateral ibotenic acid (IBO) injection and behavioral paradigms. B: Left, representative immunostaining images of NeuN (red) in lPBN after saline control or IBO injection. Right, quantification of NeuN⁺ cell number in slPBN, dlPBN, and elPBN subnuclei after IBO injection (n=3 mice in saline group, including two males and one female, n=5 mice in IBO group, including three males and two females, unpaired t-test for each lPBN subnucleus). Scale bars: 200 μm for lower magnification and 20 μm for boxed higher magnification, respectively. C: No detected differences were observed in falling latencies from the rotarod between the saline and IBO injection groups (n=7 mice per group, including four males and three females). D–H: Reflexive response tests. No significant differences were observed in withdrawal responses to von Frey filament (D), brush (E), radiant heat (F), dry ice (G), and hot plate (H) stimulation (n=6–7 mice, including 3–4 males and three females per group). I–K: lPBN-lesioned mice showed significantly reduced licking behaviors evoked by hot plate (I), skin pinching (J), and toe clipping (K) (n=6–7 mice, including 3–4 males and three females per group). L: lPBN-lesioned mice (n=7 mice per group, including four males and three females) showed reduced writhing behavior after acetic acid injection. Green and red circles represent male and female mice, respectively. Behavioral data are mean±SEM, unpaired t-test. ns: No significance; ^*: P<0.05; ^**: P<0.01; ^***: P<0.001.