Cardiovascular changes during spontaneous micturition in conscious cats

Area of Science:

• Cardiovascular Physiology
• Urology
• Autonomic Nervous System

Background:

• Micturition involves complex physiological processes.
• Understanding the hemodynamic adjustments during urination is crucial for physiological and clinical insights.

Purpose of the Study:

• To investigate the hemodynamic alterations during spontaneous micturition in conscious cats.
• To elucidate the role of the autonomic nervous system in regulating cardiovascular function during urination.

Main Methods:

• Continuous monitoring of arterial blood pressure, heart rate (HR), and cardiac output (CO) in conscious cats.
• Measurement of regional blood flows (superior mesenteric, renal, external iliac) using electromagnetic flow probes.
• Assessment of regional conductances and the effect of sympathectomy on vasomotor responses.

Main Results:

• Spontaneous micturition caused minimal change in mean arterial pressure but significant decreases in HR and CO.
• Total peripheral conductance decreased, with marked reductions in visceral and hindlimb blood flows.
• Local sympathectomy abolished the observed vasomotor changes, indicating sympathetic nervous system involvement.

Conclusions:

• Spontaneous micturition is associated with substantial changes in cardiac function and systemic circulation.
• Decreased cardiac output during micturition is compensated by diffuse nervous systemic vasoconstriction, maintaining arterial blood pressure.
• The sympathetic nervous system plays a key role in mediating hemodynamic adjustments during urination.