Atrial acetylcholinesterase activity in various heart diseases of man

Area of Science:

• Cardiovascular Histology
• Neuroanatomy
• Cardiac Physiology

Background:

• The intrinsic nervous system of the human atrium plays a crucial role in cardiac function.
• Understanding the distribution and activity of cholinergic nerves is vital for comprehending cardiac autonomic regulation.
• Previous studies have suggested alterations in cardiac innervation in various heart diseases.

Purpose of the Study:

• To investigate the distribution and activity of acetylcholinesterase enzyme in the human atrial myocardium.
• To characterize the intrinsic nervous apparatus within the atrial tissue across different cardiac conditions.
• To determine if acetylcholinesterase activity correlates with parasympathetic abnormalities in heart disease.

Main Methods:

• Histochemical analysis of acetylcholinesterase distribution in atrial myocardial specimens.
• Examination of tissue from patients undergoing cardiac surgery for various conditions: atrial septal defect, ischemic heart disease, valvular disease, and congestive heart failure.
• Microscopic assessment of nerve net patterns and presence of nerve cells.

Main Results:

• A rich, parenchymatous, three-dimensional nerve net of acetylcholinesterase-positive axons was consistently observed in the human atrial myocardium.
• Small groups of acetylcholinesterase-positive nerve cells were identified in some specimens.
• No significant differences in acetylcholinesterase distribution or nervous apparatus pattern were found among the different patient groups.
• Non-specific cholinesterase activity was absent in all specimens.

Conclusions:

• The human atrial myocardium is abundantly supplied with intrinsic cholinergic (post-ganglionic vagal) axons.
• Acetylcholinesterase activity is unlikely to be a primary determinant of parasympathetic abnormalities observed in cardiac diseases, particularly in myocardial pump failure.