Glasgow Meeting - May 2003

Effects of Thiopental Sodium, Midazolam, Propofol and Ketamine on Endothelial Nitric Oxide in Rat Thoracic Aortic Rings

Jung Un Lee, Bong Jin Kang, Su Chang Son Department of Anesthesia and Pain Medicine, Chungnam University Hospital, Daejeon, Korea

Background and Goal of study : The effects of thiopental sodium, midazolam, propofol and ketamine on endothelial nitric oxide have been studied in the strips of rat thoracic aortic rings contracted with phenylephrine( PE ).

Materials and Methods : Each ring of thoracic aorta was suspended on wire supports in a 20 ml tissue bath under 2 g of resting tension. All tissues were bathed in Tris Tyrode solution at 37°C and 100 % oxygen was supplied.

Results and Discussion :

1. Thiopental sodium(10-5M) did not have any effect on PE induced contractions of aortic rings but midazolam(10-6M), propofol(10-4M) and ketamine(10-3M) significantly(p<0.05) inhibited PE induced contractions of aortic rings respectively.

2. Midazolam 10-6M and propofol 10-4 M induced relaxation of aortic rings were recovered with L-NAME pretreatment but ketamine induced relaxation was not recovered with L-NAME pretreatment.

3. Midazolam 10-6M induced relaxation was not recovered with methylene blue pretreatment but propofol 10-4M induced relaxation was recovered with methylene blue.

4. Indomethacine pretreatment induced further relaxation of midazolam or propofol induced relaxation of aortic rings.

Conclusion : From the results obtained with this experiments, it is concluded that midazolam, propofol and ketamine but not thiopental sodium relax rat thoracic aortic rings and the relaxation effects of midazolam and propofol are endothelium dependent. And at least, in part, cyclooxygenase inhibition is related with midazolam or propofol induced relaxation and guanylate cyclase activation with propofol induced relaxation.