Cardiac acetylcholine concentration in the rat.

Area of Science:

• Cardiovascular Physiology
• Neurochemistry

Background:

• Acetylcholine (ACh) concentration in the rat heart exhibits variable reported values.
• The method used for animal sacrifice may significantly influence measured cardiac ACh levels.

Purpose of the Study:

• To compare cardiac ACh concentrations obtained using two different animal sacrifice methods: in vivo microwave irradiation versus decapitation followed by in vitro irradiation.
• To investigate the impact of post-decapitation standing time on cardiac ACh levels.

Main Methods:

• Rats were sacrificed using either in vivo microwave irradiation or decapitation followed by in vitro irradiation of the heart.
• Cardiac ACh concentrations were measured in different heart chambers (right atrium, left atrium, right ventricle, left ventricle).

Main Results:

• Significant differences in cardiac ACh concentration were observed between the in vivo microwave irradiation group and the decapitation groups.
• In decapitated animals, cardiac ACh concentration decreased progressively over time.
• Specific ACh concentrations were reported for the right atrium (4.62 ± 1.57 nmol/g), left atrium (2.58 ± 1.01 nmol/g), right ventricle (2.76 ± 1.00 nmol/g), and left ventricle (2.12 ± 0.70 nmol/g).

Conclusions:

• In vivo microwave irradiation is a more appropriate method for accurately determining cardiac acetylcholine concentration in rats.
• The chosen sacrifice method critically impacts the reliability of cardiac ACh measurements.