[Electrical responses of intact aortic endothelium in rats with experimental diabetes]

The changes in electrical properties of intact aortic endothelial cells from streptozotocin-induced diabetic rats were investigated. The mean resting membrane potential of unstimulated endothelium was significantly less negative (-32.7 +/- 0.8 mV) as compared with the aged-matched control group (-41.2 +/- 0.9 MB). In diabetic rat aortic strips, acetylcholine (2 microM) hyperpolarized endothelial cells to -57.6 +/- 1.1 mV, whereas in control group the hyperpolarization reached -64.4 +/- 0.9 mV. The amplitude of the hyperpolarization in diabetic rats, however, was not significantly different from the control group (24.9 +/- 1.1 mV and 23.2 +/- 0.9 mV, respectively). It was concluded that endothelial cells of diabetic rat aorta have less negative membrane potential values at rest and during acetylcholine stimulation that may partially account for the suppressed endothelium-dependent relaxation in streptozotocin-induced diabetic rats.