Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

The altered metabolism of CO in diabetes has been demonstrated. The vasoactive effects of CO in diabetes, however, were unknown and was investigated. The CO-induced vasorelaxation of tail artery tissues from streptozotocin-induced diabetic rats was significantly decreased as compared to that in non-diabetic control rats. Single channel conductance of KCa channels in diabetic tail artery smooth muscle cells (SMCs) was not different from that of normal SMCs, being around 225 pS. However, the gating pattern of KCa channels was significantly different between control SMCs and diabetic SMCs. CO (10 µM) had no effect on the single channel conductance of KCa channels in diabetic or non-diabetic SMCs. In control SMCs, CO at 10 µM induced a 81±24% increase in the mean open probability of single KCa channels. In contrast, at the same concentration CO did not alter the mean open probability of KCa channels in diabetic SMCs. Our results suggest that the decreased vasorelaxant effect of CO in diabetic rats could be related to a reduced sensitivity of KCa channels in the diabetic SMCs to CO. (Supported by research grants from Heart & Stroke Foundation of Canada, NSERC of Canada, and Saskatchewan Lung Association.)

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Presentation Number SAwang, r0200
Keywords: carbon monoxide, diabetes, Kca channels, patch-clamp, smooth muscle