Rapid identification of correctly located intracerebroventricular cannula in the rat

Area of Science:

• Neuroscience
• Radiology
• Surgical Techniques

Background:

• Accurate cannula placement is crucial for precise drug delivery in rodent brain research.
• Stereotaxic surgery requires reliable methods for intraoperative verification of instrument positioning.

Purpose of the Study:

• To develop and validate a radiographic method for confirming correct cannula placement in the rat ventricular system.
• To correlate the extent of ventricular spread with neurochemical and behavioral outcomes.

Main Methods:

• A radiographic technique involving infusion of thorium dioxide suspension into the rat lateral ventricle.
• Stereotaxic guidance for cannula placement.
• Lateral X-ray imaging of the in situ brain to visualize thorium dioxide distribution.
• Co-injection of 6-hydroxydopamine with thorium dioxide.
• Measurement of striatal dopamine depletion and conditioned avoidance responses.

Main Results:

• A distinct thorium dioxide shadow on lateral X-rays confirmed correct cannula placement.
• The degree of thorium dioxide spread correlated with striatal dopamine depletions.
• Ventricular spread also correlated with observed changes in conditioned avoidance responses.

Conclusions:

• Radiographic visualization with thorium dioxide provides a reliable method for verifying cannula placement in rat brain ventricular systems.
• This technique allows for precise correlation between drug spread, neurochemical changes, and behavioral effects in preclinical research.