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This Article Full Text Full Text (PDF) All Versions of this Article: 92/6/1029    most recent expphysiol.2007.038703v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Howarth, F. C. Articles by Qureshi, M. A. Search for Related Content PubMed PubMed Citation Articles by Howarth, F. C. Articles by Qureshi, M. A.

¹ Department of Physiology, Faculty of Medicine & Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, United Arab Emirates

Type 2 diabetes mellitus accounts for more than 90% of all cases of diabetes mellitus, and cardiovascular complications are the major cause of mortality and death in diabetic patients. The chronic effects of type 2 diabetes mellitus on heart function have been investigated in the Goto-Kakizaki (GK) rat. Experiments were performed in GK rats and age-matched Wistar control rats at 18 months of age. The progressive effects of diabetes on glucose metabolism were monitored periodically by application of the glucose tolerance test. Ventricular action potentials were measured in isolated, perfused heart. Shortening and intracellular Ca²⁺ were measured in electrically stimulated ventricular myocytes. The GK rats displayed mild fasting hyperglycaemia and progressively worsening glucose tolerance. At 18 months of age and 180 min after intraperitoneal injection of glucose (2 g (kg body weight)^–1), blood glucose was 436 ± 47 mg dl^–1 in GK rats compared with 153 ± 18 mg dl^–1 in control animals. Heart weight to body weight ratio was significantly increased in GK rats (4.10 ± 0.09 mg g^–1, n = 5) compared with control animals (3.36 ± 0.22 mg g^–1, n = 4). Spontaneous heart rate was slightly reduced in GK rats compared with control rats. Although the amplitude of shortening was not altered, the amplitude of the Ca²⁺ transient was significantly increased in myocytes from GK rats (0.78 ± 0.11 ratio units) compared with control rats (0.50 ± 0.06 ratio units). Despite progressively worsening glucose metabolism, at 18 months of age the contractile function of the heart appears to be well preserved.

(Received 28 May 2007; accepted after revision 3 August 2007; first published online 3 August 2007)
Corresponding author F. C. Howarth: Department of Physiology, Faculty of Medicine & Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, United Arab Emirates. Email: chris.howarth{at}uaeu.ac.ae