Altered acetylcholine and norepinephrine concentrations in diabetic rat hearts: role of parasympathetic nervous system in diabetic cardiomyopathy

• Published in: Diabetes (New York, N.Y.) Vol. 38; no. 2; pp. 231 - 236
• Main Authors: AKIYAMA, N, OKUMURA, K, WATANABE, Y, HASHIMOTO, H, ITO, T, OGAWA, K, SATAKE, T
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01.02.1989
• Subjects: Acetylcholine - analysis; Acetylcholinesterase - metabolism; Animals; Biological and medical sciences; Cardiomyopathies - etiology; Cardiomyopathies - physiopathology; Choline O-Acetyltransferase - metabolism; Diabetes Mellitus, Experimental - complications; Diabetes Mellitus, Experimental - metabolism; Diabetes Mellitus, Experimental - physiopathology; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Heart - drug effects; Insulin - therapeutic use; Male; Medical sciences; Myocardium - analysis; Myocardium - enzymology; Norepinephrine - analysis; Parasympathetic Nervous System - physiopathology; Rats; Rats, Inbred Strains; Reference Values; Heart; Animal model; Rat; Cardiomyopathy; Diabetes mellitus; Rodentia; Aminoacid derivative hormone; Concentration; Catecholamine; Parasympathic nervous system; Vertebrata; Mammalia; Acetylcholine; Norepinephrine; Sympathic nervous system
• ISSN: 0012-1797; 1939-327X
• DOI: 10.2337/diab.38.2.231

The concentrations of acetylcholine (ACh) as a parasympathetic marker and norepinephrine (NE) as a sympathetic marker were investigated in the hearts of rats 2, 4, and 8 wk after the induction of diabetes by an injection of streptozocin (STZ; 65 mg/kg i.v.). ACh and NE were measured by high-performance liquid chromatography with electrochemical detection. Diabetic rats showed low body weight and heart weight at 2, 4, and 8 wk and higher heart-to-body weight ratio and bradycardia at 8 wk, almost all of which were normalized after insulin treatment. Myocardial ACh and NE concentrations in the diabetic rats at 2 and 4 wk were not significantly different from those in age-matched control rats. However, ACh and NE concentrations in the diabetic rats at 8 wk significantly increased compared with the control rats. Diabetic rats at 8 wk also had increased myocardial choline concentration and choline acetyltransferase activity and decreased acetylcholinesterase activity. Insulin treatment normalized all of these changes in the diabetic rats. Thus, in STZ-induced diabetes (STZ-D), the concentrations of both cholinergic and noradrenergic neurotransmitters in the myocardium increased. The results of this study confirm a previously reported increase in sympathetic activity to the heart and also indicate that there is an increase in the synthesis and a decrease in the metabolism of ACh in STZ-D and that adequate insulin treatment normalizes these changes.