Dextran as a radioactive microsphere suspending agent: severe hypotensive effect in rat

Area of Science:

• Cardiovascular Physiology
• Pharmacology
• Biomedical Engineering

Background:

• Radioactive microspheres are used to measure blood flow.
• Suspending agents can potentially affect hemodynamic measurements.
• Understanding the impact of suspending solutions is crucial for accurate research.

Purpose of the Study:

• To evaluate the hemodynamic effects of different radioactive microsphere suspending solutions.
• To determine if the suspending agent or microspheres impact cardiovascular parameters.
• To identify a safe suspending solution for microsphere studies in rats.

Main Methods:

• Male Sprague-Dawley rats underwent single left ventricular injections.
• Carbonized radioactive microspheres were suspended in 10% dextran with Tween or isotonic saline with Tween.
• Hemodynamic parameters (arterial pressure, heart rate) were monitored before and after injections.
• Control studies used suspending solutions without microspheres.

Main Results:

• 10% dextran solution, with or without Tween, caused significant reductions in arterial pressure and heart rate.
• Isotonic saline with Tween only decreased heart rate.
• Radioactive microspheres suspended in isotonic saline did not alter arterial pressure or heart rate.

Conclusions:

• 10% dextran solution induces a severe hypotensive response in rats.
• Isotonic saline is a suitable suspending agent for radioactive microspheres in rat hemodynamic studies.
• The choice of suspending solution is critical for accurate microsphere-based blood flow measurements.