Journal: American Journal of Physiology - Lung Cellular and Molecular Physiology

Article Title: Episodic stimulation of central chemoreceptor neurons elicits disordered breathing and autonomic dysfunction in volume overload heart failure

doi: 10.1152/ajplung.00007.2019

Figure Lengend Snippet: Ventilatory plasticity induced by episodic hypercapnic stimulation in heart failure (HF) is retrotrapezoid nucleus (RTN) chemoreceptor neuron-dependent. A : schematic of episodic hypercapnic stimulation (EHS) paradigm ( top panel ). Effect of EHS on ventilation (ΔR f ) during pre- and post-EHS phases. Note that during the post-EHS phase, Sham+Veh rats showed ventilatory depression, and this effect was absent in HF+Veh rats. Selective ablation of RTN neurons by substance P-conjugated saporin (SSP-SAP) toxin normalizes the post-EHS ventilatory response in HF rats. B : representative traces of ventilation pre- and post-EHS in all experimental groups. C – E : summary data of tidal volume (ΔV T ), respiratory frequency (ΔR f ), and minute ventilation (ΔV̇ e ) during post-EHS phase, respectively. Data represent mean ± SE ( A ) while box and whiskers represent median ± range ( C – E ). One-way ANOVA followed by Holm-Sidak post hoc test; n = 6 rats per group. * P < 0.05 vs. Sham+Veh; + P < 0.05 vs. HF+Veh.

Article Snippet: Calculations of coherence between V T and systolic blood pressure (SBP) signals were assessed before and after episodic hypercapnic stimulation using Matlab software (R2106a version, Natick, MA).

Techniques:

Journal: American Journal of Physiology - Lung Cellular and Molecular Physiology

Article Title: Episodic stimulation of central chemoreceptor neurons elicits disordered breathing and autonomic dysfunction in volume overload heart failure

doi: 10.1152/ajplung.00007.2019

Figure Lengend Snippet: Selective ablation of retrotrapezoid nucleus (RTN) chemosensory neurons prevents ventilatory disturbances elicited by episodic hypercapnic stimulation. A : representative traces of ventilation during pre- and post-episodic hypercapnic stimulation (EHS) phases. Arrows point to disturbances in breathing patterns such as apneas/hypopneas. B and C : representative Poincaré plots and histograms during pre- and post-EHS phases. D and E : summary data of short-term (SD1) ( D ) and long-term variability (SD2) ( E ), and coefficient of variation (CV) of tidal volume (V T ) ( F ) during pre- and post-EHS phases. Substance P-conjugated saporin (SSP-SAP) toxin injection in the RTN diminished breath-to-breath and V T amplitude variability in the post-EHS phase in heart failure (HF) rats. Box and whiskers represent median ± range. Two-way ANOVA followed by Holm-Sidak post hoc tests; n = 6 rats per group. * P < 0.05 vs. Sham+Veh Pre; # P < 0.05 vs. HF+Veh Pre; + P < 0.05 vs. Sham+Veh Post; † P < 0.05 vs. HF+Veh Post.

Article Snippet: Calculations of coherence between V T and systolic blood pressure (SBP) signals were assessed before and after episodic hypercapnic stimulation using Matlab software (R2106a version, Natick, MA).

Techniques: Injection

Journal: American Journal of Physiology - Lung Cellular and Molecular Physiology

Article Title: Episodic stimulation of central chemoreceptor neurons elicits disordered breathing and autonomic dysfunction in volume overload heart failure

doi: 10.1152/ajplung.00007.2019

Figure Lengend Snippet: Episodic hypercapnic stimulation further increases active expiration in heart failure (HF) rats. A : representative traces of one breathing cycle pre- (continuous traces) and post- (segmented traces)-episodic hypercapnic stimulation (EHS) in 1 Sham+Veh rat, 1 Sham+SSP-SAP-treated rat, 1 HF+Veh rat, and 1 HF+SSP-SAP-treated rat. In HF rats, the early expiratory flow (E1) was reduced, whereas the late expiratory flow (E2) was increased compared with Sham rats. B : summary data showing E2/E1 ratio. C : summary of expiratory time obtained in 20 consecutive respiratory cycles in all groups, pre- and post-EHS. Box and whiskers represent median ± range. Two-way ANOVA followed by post hoc analysis of Holm-Sidak; n = 6 rats per group. * P < 0.05 vs. Sham+Veh; + P < 0.05 vs. Sham+SSP-SAP; † P < 0.05 vs. HF+SSP-SAP; @ P < 0.05 vs. HF+Veh post-EHS.

Article Snippet: Calculations of coherence between V T and systolic blood pressure (SBP) signals were assessed before and after episodic hypercapnic stimulation using Matlab software (R2106a version, Natick, MA).

Techniques:

Journal: American Journal of Physiology - Lung Cellular and Molecular Physiology

Article Title: Episodic stimulation of central chemoreceptor neurons elicits disordered breathing and autonomic dysfunction in volume overload heart failure

doi: 10.1152/ajplung.00007.2019

Figure Lengend Snippet: Episodic hypercapnic stimulation-induced respiratory-cardiovascular coupling in heart failure depends on intact retrotrapezoid nucleus (RTN) chemoreceptor neurons. A : representative traces of respiratory flow, respiratory frequency (R f ), blood pressure (BP), and systolic blood pressure (SBP) in 1 rat per group during pre- and post-episodic hypercapnic stimulation (EHS) phase. Segments where coupling between ventilatory and cardiovascular signals was observed are highlighted (gray). B : summary data of coherence analysis. Note that following EHS, heart failure (HF) rats displayed an increased coherence between tidal volume (V T ) oscillation and SBP, and this was blunted in HF rats treated with substance P-conjugated saporin (SSP-SAP) toxin. Box and whiskers represent median ± range. Two-way ANOVA followed by Holm-Sidak post hoc analysis; n = 6 rats per group. # P < 0.05 vs. HF+Veh Pre-EHS. LF, low frequency.

Article Snippet: Calculations of coherence between V T and systolic blood pressure (SBP) signals were assessed before and after episodic hypercapnic stimulation using Matlab software (R2106a version, Natick, MA).

Techniques: