Interleukin 1-beta (IL-1β) enhances contractile responses in endothelium-denuded aorta from hypertensive, but not normotensive, rats

BackgroundThe chronic effects of interleukin 1-beta (IL-β) on vascular reactivity include augmentation of contraction and relaxation. Few studies have assessed the acute effects of IL-1β in vessels from hypertensive and normotensive rats. We hypothesized that IL-1β would enhance constriction in aorta from stroke prone spontaneously hypertensive rats (SHRSP).MethodsEndothelium denuded aortic rings from 12 week-old SHRSP and Wistar Kyoto (WKY) rats were mounted in a myograph and incubated with IL-1β (20 ng/ml) for 1 h before construction of a phenylephrine dose response curve. Indomethacin (1 μM) and PP-2 (1 μM) were utilized to inhibit cyclooxygenase (COX) and Src-kinase respectively.ResultsIn aorta from SHRSP, IL-1β caused a significant increase in the force generated over the hour incubation; inhibition of COX or Src-kinase prevented this. The maximum phenylephrine-induced contraction was greater in aorta from SHRSP incubated with IL-1β than control. COX or Src-kinase inhibition prevented this. IL-1β had no effect on the vessels from WKY rats.ConclusionsThese novel data suggest that IL-1β has rapid effects on vascular smooth muscle from hypertensive rats to produce constriction and to enhance phenylephrine-induced constriction. The COX and Src-kinase pathways appear to be involved in this response.