Related Experiment Videos
Pressure diuresis and autonomic function in conscious dogs
P H Brand1, K B Coyne, K A Kostrzewski
1Department of Physiology and Biophysics, Medical College of Ohio, Toledo 43699-0008.
The American Journal of Physiology
|October 1, 1991
Summary
This study shows that pressure diuresis, a key regulator of arterial blood pressure, can be observed in conscious dogs. Blocking autonomic reflexes significantly enhances the correlation between arterial pressure and urine output.
Area of Science:
- Physiology
- Nephrology
- Cardiovascular Regulation
Background:
- Pressure diuresis is a primary long-term regulator of arterial blood pressure (AP).
- Previous studies relied on pharmacological or surgical interventions to assess pressure diuresis.
- Minimal experimental interference is crucial for understanding physiological regulation.
Purpose of the Study:
- To evaluate pressure diuresis in conscious dogs with minimal experimental interference.
- To investigate the role of autonomic reflexes in modulating pressure diuresis.
- To determine the direct impact of arterial pressure on renal function.
Main Methods:
- Chronic instrumentation of conscious dogs with aortic and urinary bladder catheters.
- Induction of a 10% increase in AP via arousal (increased light and sound).
- Repeated studies during autonomic ganglionic blockade using hexamethonium.
Main Results:
- During arousal, urine flow (UV) and sodium excretion (UNa+V) showed a significant correlation with AP.
- Atrial natriuretic factor levels remained unaffected, indicating no contribution from this hormone.
- Autonomic blockade markedly increased the correlation between AP and UV/UNa+V.
Conclusions:
- The pressure-diuresis effect on UV and UNa+V is detectable in intact animals.
- Autonomic reflexes can modulate the pressure-diuresis mechanism.
- When autonomic reflexes are blocked, pressure diuresis becomes a major determinant of urine output and sodium excretion.