Key result
In unconscious rats with obstructive apnea, renal denervation exacerbated hypotension (-16 vs -12 mmHg) and attenuated bradycardia (9 vs -16 bpm) compared to sham (P<0.01).
Why the study?
Does renal denervation alter blood pressure, heart rate, and sodium/water excretion during acute total obstructive apnea in rats?
Does renal denervation alter blood pressure, heart rate, and sodium/water excretion during acute total obstructive apnea in rats?
In a rat model of obstructive apnea, renal denervation exacerbates hypotension, attenuates bradycardia, and increases sodium and water excretion, highlighting the role of renal sympathetic nerve activity in these physiological responses.
Should not inform clinical renal denervation decisions; hypothesis-generating for renal sympathetic modulation of apnea responses.
Obstructive apnea (OA) can exert significant effects on renal sympathetic nerve activity (RSNA) and hemodynamic parameters. The present study focuses on the modulatory actions of RSNA on OA-induced sodium and water retention. The experiments were performed in renal-denervated rats (D; N = 9), which were compared to sham (S; N = 9) rats. Mean arterial pressure (MAP) and heart rate (HR) were assessed via an intrafemoral catheter. A catheter was inserted into the bladder for urinary measurements. OA episodes were induced via occlusion of the catheter inserted into the trachea. After an equilibration period, OA was induced for 20 s every 2 min and the changes in urine, MAP, HR and RSNA were recorded. Renal denervation did not alter resting MAP (S: 113 +/- 4 vs D: 115 +/- 4 mmHg) or HR (S: 340 +/- 12 vs D: 368 +/- 11 bpm). An OA episode resulted in decreased HR and MAP in both groups, but D rats showed exacerbated hypotension and attenuated bradycardia (S: -12 +/- 1 mmHg and -16 +/- 2 bpm vs D: -16 +/- 1 mmHg and 9 +/- 2 bpm; P < 0.01). The basal urinary parameters did not change during or after OA in S rats. However, D rats showed significant increases both during and after OA. Renal sympathetic nerve activity in S rats increased (34 +/- 9%) during apnea episodes. These results indicate that renal denervation induces elevations of sodium content and urine volume and alters bradycardia and hypotension patterns during total OA in unconscious rats.
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Franquini et al. (2009) studied Obstructive apnea (n=18). Renal denervation vs. Sham was evaluated on Change in mean arterial pressure (MAP) during obstructive apnea (p=<0.01). In unconscious rats with obstructive apnea, renal denervation exacerbated hypotension (-16 vs -12 mmHg) and attenuated bradycardia (9 vs -16 bpm) compared to sham (P<0.01).
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