Pump perfusion abolishes autoregulation possibly via prostaglandin release

Area of Science:

• Physiology
• Pharmacology

Background:

• Autoregulation is crucial for maintaining stable blood flow.
• Understanding factors affecting autoregulation is vital for physiological research.

Purpose of the Study:

• To investigate the impact of pump perfusion on hindleg autoregulation.
• To elucidate the role of prostaglandins and serotonin in this process.

Main Methods:

• Studied autoregulation in anesthetized cats using electromagnetic flow probes and pressure measurements.
• Administered indomethacin (cyclooxygenase inhibitor) and ketanserin (serotonin 2 receptor blocker).

Main Results:

• Pump perfusion abolished autoregulation, resulting in a linear pressure-flow relation.
• Indomethacin partially restored autoregulation during pumping and increased resistance.
• Ketanserin did not prevent the slow vasoconstrictor influence observed after prostaglandin synthesis blockade.

Conclusions:

• Pump perfusion impairs autoregulation through a prostaglandin-dependent mechanism.
• Prostaglandin synthesis inhibition unmasks a slow vasoconstrictor influence in the vascular bed.