The vasoactive effects of ketamine on aortic and pulmonary arteries have not been clearly characterized. Nevertheless, it has been recommended to avoid ketamine in systemic and pulmonary hypertension because of its tendency to increase systemic
and
pulmonary vascular resistance.
This study was designed to investigate and compare the direct effects of ketamine on isolated rat aortic and pulmonary arteries, with or without intact endothelium.
The optimal resting tension (Lmax) of each ring was searched based on contractile responses to 3.7(10E6M norepinephrine. Once the Lmax was obtained, the peak developed tension was recorded as the control.
Thereafter in the second part of the experiments., prior to ketamine exposure, the endothelium was denuded which was confirmed pharmacologically using norepinephrine(3.7(10E6M) and acetylcholine(10E-6M).
In groups with intact endothelium, 3(10E3M ketamine relaxed aortic and pulmonary artery ring by -10.3(5.6%, -17.8(4.4%, respectively.
In groups without intact endothelium, 3(10E3M ketamine relaxed aortic and pulmonary artery ring by -09.9(3.6%, -14.2(3.8%, respectively. It was statistically significant.
In groups with or without intact endothelium, 0.1(10E3M ketamine relaxed aortic and pulmonary artery ring. But it was statistically insignificant.
We conclude that ketamine is a powerful aortic and pulmonary artery dilator in vitro and that is endothelium independent.
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