Contractile properties of left ventricular papillary muscles and atria from streptozotocin-diabetic and from non-diabetic rats fed a 40% galactose diet were measured in vitro. There was a characteristic slowing of twitch responses for both tissues and both treatments (P < 0.05). Time to peak contraction was prolonged by 18-33% and maximum rate of contraction was reduced by 10-17%. Relaxation was also affected, with a 13-37% increase in half-relaxation time and a 7-25% reduction in the maximum rate of relaxation. There were treatment differences between papillary muscles and left atrium, diabetes having a more marked effect on the former, whereas galactosaemia caused more pronounced changes in the latter. The resting beat rate of the right atrium was 22% reduced in diabetic and galactosaemic rats (P < 0.01). When maximally stimulated with isoprenaline, beat rate did not rise to the level of stimulated controls (P < 0.01). Papillary muscle speed-related contractile properties also showed a reduced response to isoprenaline in diabetic and galactosaemic groups compared to normal controls. The greatest deficit was found for maximum rate of relaxation where responsiveness was 41 and 34% less for diabetic and galactosaemic groups respectively (P < 0.01). Polyol pathway metabolites in diabetic ventricles were increased 8-fold. In galactosaemic rats galactitol accumulation led to a 530-fold increase in polyols. The data suggest that polyol pathway activity may be an important factor in the aetiology of contractile and chronotropic changes in diabetic and galactosaemic cardiomyopathy.

This article has been cited by other articles:

				V. Sharma, P. Dhillon, R. Wambolt, H. Parsons, R. Brownsey, M. F. Allard, and J. H. McNeill Metoprolol improves cardiac function and modulates cardiac metabolism in the streptozotocin-diabetic rat Am J Physiol Heart Circ Physiol, April 1, 2008; 294(4): H1609 - H1620. [Abstract] [Full Text] [PDF]

				X. Xin, S. Chen, Z. A. Khan, and S. Chakrabarti Akt activation and augmented fibronectin production in hyperhexosemia Am J Physiol Endocrinol Metab, October 1, 2007; 293(4): E1036 - E1044. [Abstract] [Full Text] [PDF]