Tags

Type your tag names separated by a space and hit enter

Role of the afferent renal nerves in sodium homeostasis and blood pressure regulation in rats.
Exp Physiol 2019; 104(8):1306-1323EP

Abstract

NEW FINDINGS

What is the central question of this study? What are the differential roles of the mechanosensitive and chemosensitive afferent renal nerves in the reno-renal reflex that promotes natriuresis, sympathoinhibition and normotension during acute and chronic challenges to sodium homeostasis? What is the main finding and its importance? The mechanosensitive afferent renal nerves contribute to an acute natriuretic sympathoinhibitory reno-renal reflex that may be integrated within the paraventricular nucleus of the hypothalamus. Critically, the afferent renal nerves are required for the maintenance of salt resistance in Sprague-Dawley and Dahl salt-resistant rats and attenuate the development of Dahl salt-sensitive hypertension.

ABSTRACT

These studies tested the hypothesis that in normotensive salt-resistant rat phenotypes the mechanosensitive afferent renal nerve (ARN) reno-renal reflex promotes natriuresis, sympathoinhibition and normotension during acute and chronic challenges to fluid and electrolyte homeostasis. Selective ARN ablation was conducted prior to (1) an acute isotonic volume expansion (VE) or 1 m NaCl infusion in Sprague-Dawley (SD) rats and (2) chronic high salt intake in SD, Dahl salt-resistant (DSR), and Dahl salt-sensitive (DSS) rats. ARN responsiveness following high salt intake was assessed ex vivo in response to noradrenaline and sodium concentration (SD, DSR and DSS) and via in vivo manipulation of renal pelvic pressure and sodium concentration (SD and DSS). ARN ablation attenuated the natriuretic and sympathoinhibitory responses to an acute VE [peak natriuresis (µeq min-1) sham 52 ± 5 vs. ARN ablation 28 ± 3, P < 0.05], but not a hypertonic saline infusion in SD rats. High salt (HS) intake enhanced ARN reno-renal reflex-mediated natriuresis in response to direct increases in renal pelvic pressure (mechanoreceptor stimulus) in vivo and ARN responsiveness to noradrenaline ex vivo in SD, but not DSS, rats. In vivo and ex vivo ARN responsiveness to increased renal pelvic sodium concentration (chemoreceptor stimulus) was unaltered during HS intake. ARN ablation evoked sympathetically mediated salt-sensitive hypertension in SD rats [MAP (mmHg): sham normal salt 102 ± 2 vs. sham HS 104 ± 2 vs. ARN ablation normal salt 103 ± 2 vs. ARN ablation HS 121 ± 2, P < 0.05] and DSR rats and exacerbated DSS hypertension. The mechanosensitive ARNs mediate an acute sympathoinhibitory natriuretic reflex and counter the development of salt-sensitive hypertension.

Authors+Show Affiliations

Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA.Department of Pharmacology & Experimental Therapeutics and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31074108

Citation

Frame, Alissa A., et al. "Role of the Afferent Renal Nerves in Sodium Homeostasis and Blood Pressure Regulation in Rats." Experimental Physiology, vol. 104, no. 8, 2019, pp. 1306-1323.
Frame AA, Carmichael CY, Kuwabara JT, et al. Role of the afferent renal nerves in sodium homeostasis and blood pressure regulation in rats. Exp Physiol. 2019;104(8):1306-1323.
Frame, A. A., Carmichael, C. Y., Kuwabara, J. T., Cunningham, J. T., & Wainford, R. D. (2019). Role of the afferent renal nerves in sodium homeostasis and blood pressure regulation in rats. Experimental Physiology, 104(8), pp. 1306-1323. doi:10.1113/EP087700.
Frame AA, et al. Role of the Afferent Renal Nerves in Sodium Homeostasis and Blood Pressure Regulation in Rats. Exp Physiol. 2019;104(8):1306-1323. PubMed PMID: 31074108.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Role of the afferent renal nerves in sodium homeostasis and blood pressure regulation in rats. AU - Frame,Alissa A, AU - Carmichael,Casey Y, AU - Kuwabara,Jill T, AU - Cunningham,J Thomas, AU - Wainford,Richard D, Y1 - 2019/05/27/ PY - 2019/03/07/received PY - 2019/05/09/accepted PY - 2019/5/11/pubmed PY - 2019/5/11/medline PY - 2019/5/11/entrez KW - afferent renal nerves KW - blood pressure KW - sodium homeostasis SP - 1306 EP - 1323 JF - Experimental physiology JO - Exp. Physiol. VL - 104 IS - 8 N2 - NEW FINDINGS: What is the central question of this study? What are the differential roles of the mechanosensitive and chemosensitive afferent renal nerves in the reno-renal reflex that promotes natriuresis, sympathoinhibition and normotension during acute and chronic challenges to sodium homeostasis? What is the main finding and its importance? The mechanosensitive afferent renal nerves contribute to an acute natriuretic sympathoinhibitory reno-renal reflex that may be integrated within the paraventricular nucleus of the hypothalamus. Critically, the afferent renal nerves are required for the maintenance of salt resistance in Sprague-Dawley and Dahl salt-resistant rats and attenuate the development of Dahl salt-sensitive hypertension. ABSTRACT: These studies tested the hypothesis that in normotensive salt-resistant rat phenotypes the mechanosensitive afferent renal nerve (ARN) reno-renal reflex promotes natriuresis, sympathoinhibition and normotension during acute and chronic challenges to fluid and electrolyte homeostasis. Selective ARN ablation was conducted prior to (1) an acute isotonic volume expansion (VE) or 1 m NaCl infusion in Sprague-Dawley (SD) rats and (2) chronic high salt intake in SD, Dahl salt-resistant (DSR), and Dahl salt-sensitive (DSS) rats. ARN responsiveness following high salt intake was assessed ex vivo in response to noradrenaline and sodium concentration (SD, DSR and DSS) and via in vivo manipulation of renal pelvic pressure and sodium concentration (SD and DSS). ARN ablation attenuated the natriuretic and sympathoinhibitory responses to an acute VE [peak natriuresis (µeq min-1) sham 52 ± 5 vs. ARN ablation 28 ± 3, P < 0.05], but not a hypertonic saline infusion in SD rats. High salt (HS) intake enhanced ARN reno-renal reflex-mediated natriuresis in response to direct increases in renal pelvic pressure (mechanoreceptor stimulus) in vivo and ARN responsiveness to noradrenaline ex vivo in SD, but not DSS, rats. In vivo and ex vivo ARN responsiveness to increased renal pelvic sodium concentration (chemoreceptor stimulus) was unaltered during HS intake. ARN ablation evoked sympathetically mediated salt-sensitive hypertension in SD rats [MAP (mmHg): sham normal salt 102 ± 2 vs. sham HS 104 ± 2 vs. ARN ablation normal salt 103 ± 2 vs. ARN ablation HS 121 ± 2, P < 0.05] and DSR rats and exacerbated DSS hypertension. The mechanosensitive ARNs mediate an acute sympathoinhibitory natriuretic reflex and counter the development of salt-sensitive hypertension. SN - 1469-445X UR - https://www.unboundmedicine.com/medline/citation/31074108/Role_of_the_afferent_renal_nerves_in_sodium_homeostasis_and_blood_pressure_regulation_in_rats_ L2 - https://doi.org/10.1113/EP087700 DB - PRIME DP - Unbound Medicine ER -