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Quantifying Acute Changes in Renal Sympathetic Nerve Activity in Response to Central Nervous System Manipulations in Anesthetized Rats
Published on: September 11, 2018
Sildenafil acts on the central nervous system increasing sympathetic activity
Rubens Fazan1, Domitila A Huber, Carlos Alberto A Silva
1Dept. of Physiology, School of Medicine of Ribeirão Preto-USP, Av. Bandeirantes 3900, 14049-900, Ribeirão Preto, SP Brazil.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|April 5, 2008
Summary
Sildenafil administered centrally increases sympathetic nerve activity in rats without affecting blood pressure or baroreflexes. This central action suggests sildenafil may cause autonomic imbalance, impacting cardiovascular outcomes.
Area of Science:
- Cardiovascular Physiology
- Neuropharmacology
- Autonomic Nervous System
Background:
- Sildenafil is known for vasodilation in erectile dysfunction.
- Emerging evidence suggests sildenafil may enhance sympathetic activity.
- The central nervous system effects of sildenafil on autonomic control are not well understood.
Purpose of the Study:
- To investigate the impact of central sildenafil administration on cardiovascular autonomic control in conscious rats.
- To determine if sildenafil affects sympathetic nerve activity and baroreflex function when injected into the brain.
Main Methods:
- Sildenafil citrate was administered intracerebroventricularly (ICV) in conscious rats.
- Measurements included lumbar sympathetic nerve activity (LSNA), arterial pressure, and heart rate variability.
- Analysis involved spectral analysis and baroreflex sensitivity testing.
Main Results:
- ICV sildenafil induced tachycardia and a significant increase in LSNA (47%).
- Spectral analysis showed increased low-frequency oscillations in blood pressure and altered heart rate variability (increased LF-HF ratio).
- Baroreflex sensitivity and LSNA regulation by blood pressure remained unaffected.
Conclusions:
- Central sildenafil administration increases sympathetic nerve activity through a non-baroreflex-mediated pathway.
- This suggests sildenafil can induce a central autonomic imbalance.
- Findings highlight potential implications for cardiovascular effects during clinical sildenafil use.
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