Algogen-induced vasosensory reflexes modulate short-term heart rate variability parameters in experimental rat models

Area of Science:

• Physiology
• Cardiovascular Research
• Autonomic Nervous System

Background:

• Heart rate variability (HRV) reflects autonomic nervous system balance.
• Inflammatory mediators can influence physiological responses.
• Understanding reflex responses is crucial for cardiovascular health.

Purpose of the Study:

• To investigate the modulatory effects of algogen-induced vaso-sensory reflex responses on short-term heart rate variability (HRV) parameters.
• To compare these effects in naïve and vagotomized rat models.

Main Methods:

• Vaso-sensory reflexes were induced by intra-arterial instillation of algogens (bradykinin/histamine) into the femoral artery.
• Continuous electrocardiogram (ECG) recordings were analyzed for short-term HRV parameters.
• Time and frequency domain analyses were performed, with comparisons between saline controls, naïve, and vagotomized rats.

Main Results:

• Bradykinin and histamine significantly altered HRV parameters, indicating increased parasympathetic and decreased sympathetic influence.
• Bradykinin induced more pronounced HRV changes than histamine.
• Vagotomy significantly attenuated the HRV modulation, highlighting the vagus nerve's role.

Conclusions:

• Algogen-induced vaso-sensory reflexes modulate HRV, primarily via the vagus nerve.
• This suggests a potential cardio-protective mechanism of inflammatory mediators during acute stress.
• The findings propose a novel hypothesis on the interplay between inflammation, autonomic control, and cardiac function.