Carotid sinus nerve electrical stimulation in conscious rats attenuates systemic inflammation via chemoreceptor activation

Figures

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  Figure 1. Experimental Protocols. White bars represent the recording period before the stimulation; hatched bars represent the timeframe under electrical stimulation. After the electrical stimulation, the animals were monitored for another 2 hours (gray bars). Saline (vehicle) or LPS (1.5 mg/kg, i.v.) were injected at time 0 in all protocols.

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  Figure 2. Effect of electrical stimulation of the carotid sinus nerve (CSN) on plasma cytokines concentration in LPS induced systemic inflammation in conscious rats. Panel a: TNF (**p < 0.001 vs Control, ***p = 0.002 vs LPS) 1 hour after LPS administration. Panels b, c, and d, respectively: IL-6 (**p < 0.001 vs Control, ***p = 0.007 vs LPS), IL-1β (**p < 0.001 vs Control, ***p = 0.005 vs LPS), and IL-10 (**p < 0.001 vs Control, ***p = 0.0019 vs LPS) 3 hours after LPS administration. Number of animals is shown between parentheses.

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  Figure 3. Carotid body denervation (Ch-X) abrogates the anti-inflammatory effects of electrical stimulation of the carotid sinus nerve (CSN) on plasma cytokines concentration in LPS induced systemic inflammation in conscious rats. Panel a: TNF (**p = 0.005 vs Control) 1 hour after LPS administration. Panels b, c, and d, respectively: IL-6 (**p < 0.001 vs Control), IL-1β (**p < 0.001 vs Control), and IL-10 (**p = 0.004 vs Control) at 3 hours after LPS administration. Number of animals is shown between parentheses.

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  Figure 4. Methylatropine (MA) and Propranolol (Prop) administration abrogates the anti-inflammatory effect of electrical stimulation of the carotid sinus nerve (CSN) on plasma cytokines concentration in LPS induced systemic inflammation in conscious rats. Panel a: TNF (**p = 0.02 vs Control) 1 hour after LPS and MA administration. Panels b, c, and d, respectively: IL-6 (**p = 0.007 vs Control), IL-1β (**p = 0.002 vs Control) and IL-10 (**p = 0.01 vs Control) at 3 hours after LPS and MA administration. Panel e: TNF(**p = 0.009 vs Control) 1 hour after LPS and Prop administration. Panels f, g, and h, respectively: IL-6 (**p < 0.001 vs Control), IL-1β (**p < 0.001 vs Control), and IL-10 (**p = 0.04 vs Control) at 3 hours after LPS and Prop administration. Number of animals is shown between parentheses.

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  Figure 5. Hemodynamic responses to electrical stimulation of the carotid sinus nerve. Panel a: Tracings of pulsatile arterial pressure (PAP) [white line represents mean AP] and heart rate (HR) before, during and right after turning off the electrical stimulation. Panels b and c: Hemodynamic responses to KCN in intact and carotid body denervated rats. Panels d and e: effect of phenylephrine (PhE) in intact rats without and under methylatropine administration, respectively.