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. 2023 Jan 2;39(8):1193–1209. doi: 10.1007/s12264-022-01008-3

Fig. 8.

Fig. 8

Ablation of NTSPNMT neurons impairs the baroreflex. A Schematic of a genetic ablation strategy via injections of a virus encoding the Casp3 gene into the NTS in PNMT-Cre-ChR2-tdTomato mice. Control mice were injected with a virus devoid of the Casp3 gene. B Confocal images showing the number of NTSPNMT neurons is lower in Casp3-injected mice than in the control. Scale bar, 50 μm. C Quantitative analysis of neuronal ablation (n = 5 for control, n = 4 for Casp3; unpaired t-test). D Schematic of a strategy for the selective ablation of NTSPNMT neurons projecting to the RVLM in PNMT-Cre mice. E Confocal images showing GFP-labelled neurons are fewer in the Casp3-injected mouse than in the control. Scale bar, 50 μm. F Quantitative analysis of neuronal ablation (n = 5 for control, n = 4 for Casp3; Mann-Whitney test). GI Typical traces showing the responses of BP and HR to intravenous injection of PE (40 µg/kg, i.v.) in the three phenotypes. J, K The mean changes in ∆SBP and ∆HR in responses to intravenous injections of different doses of PE (10, 20, and 40 µg/kg; two-way ANOVA with Tukey’s multiple comparisons test). L, M The mean change in ∆SBP and ∆HR in responses to intravenous injection of SNP (30, 60, and 120 µg/kg; two-way ANOVA with Tukey’s multiple comparisons test). N, O Bradycardia and tachycardiac gains of NTSPNMT-Casp3 mice are significantly lower than in the control group. Bradycardia rather than tachycardiac gain is significantly decreased in mice with ablation of NTSPNMT neurons (Kruskal-Wallis test followed by Dunn's multiple comparisons test). P The baroreflex curve showing the individual data points for the change in ∆HR in response to induced changes in ∆SBP. Linear regression analysis shows a significant difference between groups. n = 10 mice/30 responses for control mice without loss of NTSPNMT neurons, n = 8 mice/24 responses for mice subjected to ablation of NTSPNMT neurons, n = 11 mice/33 responses for mice subjected to ablation of RVLM-projecting NTSPNMT neurons. *P <0.05, **P <0.01, ***P <0.001, ****P <0.0001.