腸間膜動脈血管の内皮除去による血管弛緩反応増強機序

Abstract

We reported that vasodilator responses to various vasodilator agents were augmented by endothelium removal. To explain this mechanism, we hypothesized that endothelium removal eliminates the release of endothelium-derived contracting factor EDCF, which counteracts the vasodilation. However, the underlying mechanism is unknown. Therefore the present study investigated the second messenger system further to investigate the mechanisms underlying enhanced vasodilator response after endothelium removal in rat mesenteric resistance arteries. Mesenteric vascular beds isolated from Wistar rats were perfused and perfusion pressure was measured. The vascular endothelium was removed by 30-s perfusion of sodium deoxycholate. Vasodilator responses to sodium nitroprusside (SNP) perfusion were markedly augmented and prolonged by endothelium removal. In preparations with intact endothelium and active tone, 5-min perfusion of sodium azide (non-speciˆc guanylate cyclase (GC) activator), ANP (membrane-linked GC activator), and 8-Br-cGMP (cGMP analogue) caused a concentration-dependent vasodilation that was markedly augmented by endothelium removal. However, vasodilation induced by YC-1 and BAY41-2272 (selective soluble GC activator) was not augmented by endothelium removal. When methylene blue (soluble GC inhibitor) was present in the medium, SNP caused a concentration-dependent vasodilation in the preparation with intact endothelium, which was less augmented by endothelium removal compared with control (preparation without methylene blue). Theseˆndings suggest that endothelium removal aŠects intracellular cGMP-mediated signal transduction system in vascular smooth muscle cells.

The state of the guanylate cyclase mechanism of vasodilatation before and after thyroidectomy in the patients presenting with toxic goiter

“…В присутствии не-специфического активатора, активатора мембран-связанной гуанилатциклазы или аналога цГМФ этот эффект усиливался, а при воздействии ингибиторов гуанилатциклазы -снижался. В то же время после удаления эндотелия вазодилатация в присутствии активатора растворимой гуанилатциклазы не изме-нялась [9]. Это экспериментальное исследование выявляет наличие в эндотелии сосудов фактора, блокирующего ГЦАМ.…”