Distribution of atrial natriuretic peptide and its effects on contraction and intracellular calcium in ventricular myocytes from streptozotocin-induced diabetic rat

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 2005-04, Vol.26 (4), p.691-700
• Main Authors: Howarth, F.C., Adem, A., Adeghate, E.A., Ali, N.A. Al, Bastaki, A.M. Al, Sorour, F.R., Hammoudi, R.O., Ghaleb, N.A., Chandler, N.J., Dobrzynski, H.
• Format: Article
• Language: English
• Subjects: Animals; Atrial Natriuretic Factor - blood; Atrial Natriuretic Factor - pharmacology; Atrial Natriuretic Factor - physiology; Atrial natriuretic peptide; Biological and medical sciences; Calcium; Diabetes; Diabetes Mellitus, Experimental - pathology; Diabetes Mellitus, Experimental - physiopathology; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Fundamental and applied biological sciences. Psychology; Heart Ventricles - drug effects; Heart Ventricles - pathology; Heart Ventricles - physiopathology; Male; Medical sciences; Muscle Cells - drug effects; Muscle Cells - physiology; Myocardial Contraction - drug effects; Myocardial Contraction - physiology; Rats; Rats, Wistar; Streptozocin - toxicity; Ventricular myocytes; Vertebrates: endocrinology
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2004.12.003

The distribution of atrial natriuretic peptide (ANP) in blood plasma and cardiac muscle and its effects on ventricular myocyte contraction and intracellular free calcium concentration [Ca 2+] i in the streptozotocin (STZ)-induced diabetic rat have been investigated. Blood plasma concentration and heart atrial and ventricular contents of ANP were significantly increased in STZ-treated rats compared to age-matched controls. STZ treatment increased the number of ventricular myocytes immunolabeled with antibodies against ANP. In control myocytes the percentage of cells that labeled positively and negatively were 17% versus 83%, respectively. However, in myocytes from STZ-treated rat the percentages were 52% versus 53%. Time to peak (TPK) shortening was significantly and characteristically prolonged in myocytes from STZ-treated rats (360 ± 5 ms) compared to controls (305 ± 5 ms). Amplitude of the Ca 2+ transient was significantly increased in myocytes from STZ-treated rats compared to controls (0.39 ± 0.02 versus 0.29 ± 0.02 fura-2 RU in controls) and treatment with ANP reduced the amplitude of the Ca 2+ transient to control levels. ANP may have a protective role in STZ-induced diabetic rat heart.