Sympathetic-renal interaction in chronic arterial pressure control

Area of Science:

• Physiology
• Nephrology
• Cardiovascular Research

Background:

• Neonatal sympathetic nervous system development influences adult cardiovascular regulation.
• Hypertension in spontaneously hypertensive rats (SHR) is linked to sympathetic overactivity.
• Kidney transplantation can alter recipient blood pressure dynamics.

Purpose of the Study:

• To investigate the long-term effects of neonatal sympathectomy on arterial pressure following renal transplantation in spontaneously hypertensive rats (SHR).
• To determine if neonatal sympathectomy in kidney donors or recipients impacts post-transplantation blood pressure.
• To assess the influence of generalized sympathetic tone reduction on hypertension and kidney graft function.

Main Methods:

• Renal transplantation experiments were conducted in spontaneously hypertensive rats (SHR) and F1-hybrids (SHR x Wistar-Kyoto rats).
• Neonatal sympathectomy was performed on donors or recipients.
• Mean arterial pressure (MAP) and renal vascular resistance were measured in conscious animals.
• Sodium sensitivity of MAP was evaluated post-transplantation.

Main Results:

• Neonatal sympathectomy in SHR recipients lowered conscious mean arterial pressure (MAP) and renal vascular resistance compared to controls.
• Kidneys from neonatally sympathectomized SHR donors resulted in lower MAP in SHR recipients.
• Neonatal sympathectomy in F1-hybrids also lowered MAP and blunted the hypertensive effect of SHR kidney grafts.
• Reduced sodium sensitivity of MAP was observed in recipients of kidneys from sympathectomized donors.

Conclusions:

• Neonatal sympathectomy induces chronic changes in SHR kidney function, leading to reduced MAP even when sympathetic tone is restored.
• A generalized reduction in sympathetic tone resets the kidney-fluid system to a lower MAP.
• Neonatal sympathectomy attenuates the hypertensive impact of SHR kidney grafts on recipients.