Effects of controlled blood loss on cardiovascular system indices and baroreflex sensitivity in anesthetized rat
DOI:
https://doi.org/10.33910/2687-1270-2025-6-3-338-349Keywords:
cardiovascular system, baroreflex, blood loss, urethane, ratsAbstract
A reduction in circulating blood volume (CBV) due to blood loss initiates a cascade of adaptive responses affecting changes in the body’s internal environment, including the functioning of visceral systems, and, in particular, the cardiovascular system. The baroreflex (BR) is a key mechanism for maintaining stable systemic arterial pressure. We hypothesized that a decrease in CBV due to blood loss leads to a disruption of compensatory circulatory mechanisms, including changes in baroreflex sensitivity. This study aimed to test this hypothesis. Experiments were conducted on urethane-anesthetized Wistar rats, in which blood loss was simulated by withdrawing 30% of the estimated CBV. Arterial pressure, heart rate, and the Algover shock index were recorded and estimated continuously. BR sensitivity was assessed using intravenous administration of the synthetic adrenergic agonist phenylephrine. A 30% CBV reduction in urethane-anesthetized rats resulted in a decreased arterial pressure, an increased Algover index, and a weakening of baroreflex sensitivity. The observed reduction in BR sensitivity may result from impaired activity of the medulla oblongata regions involved in the baroreflex. Further experimental studies are required to confirm this hypothesis.
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