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Effects of nitric oxide n peritoneal lymphatic stomata and lymph drainage via NO-cGMP-Ca~(2+) pathway

Li Yanyuan, Li Jicheng

Department of Lymphology, Institute of Cell Biology, Zhejiang University.Hangzhou 310031,Zhejiang

Abstract

To study the cell signal mechanism of nitric oxide (NO) on the peritoneal lymphatic stomata and lymph drainage in the rat, cGMP content were measured by a commercially available radioimmunoassay kit, and the [Ca~(2+)]_(i) were observed by a confocal laser scanning microscope in the cultured peritoneal mesothelial cell. Animal experiment was practiced to study the effect of NO-cGMP-Ca~(2+) pathway on the lymphatic stomata and lymph absorption. The results showed that (1) Sper/NO increased cGMP of the rat peritoneal mesothelial cell (RPMC) in a dose-dependent manner (P<0.01) compared to the control group. This effect was blocked by 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ) (P<0.05), a specific inhibitor of soluble guanylyl cyclase (sGC). The level of [Ca~(2+)]_(i) in single RPMC decreased by adding of Sper/NO (P<0.05). Pretreatment with ODQ for 10 min blocked the Sper/NO-induced decrease [Ca~(2+)]_(i). L-typed calcium channel blocker nifedipine induced an immediate and marked decrease in [Ca~(2+)]_(i) (P<0.05). After [Ca~(2+)]_(i) reached a balance again, adding Sper/NO could not change [Ca~(2+)]_(i) (P>0.05). (2) Sper/NO increased the area of the stomata (P<0.01) and the quantity of the tracer in a dose-dependent manner (P<0.05) compared to the control group. Pretreatment with ODQ significantly inhibited Sper/NO-induced change of lymphatic stomata and lymph drainage (P<0.01). Nifedipine increased the opening area of the lymphatic stomata (P<0.01) and the concentration of absorbed trypan blue of the diaphragm (P<0.05). Sper/NO could not make a further change in the samples pretreated by nifedipine (P>0.05). The results indicate that NO can decrease [Ca~(2+)]_(i) in the RPMC through the NO-cGMP pathway. This procession is related with the L- type voltage-gated Ca~(2+) channel. NO enlarges the opening area of the lymphatic stomata and enhances the lymph drainage of tracer by NO-cGMP-[Ca~(2+)]_(i) pathway.

Key words: Lymphatic stomata;Signal transduction;Mesothelial cell;Nitric oxide;Rat

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Citing This Article：

Li Yanyuan, Li Jicheng. Effects of nitric oxide n peritoneal lymphatic stomata and lymph drainage via NO-cGMP-Ca~(2+) pathway. Acta Physiol Sin 2005; 57 (1): (in Chinese with English abstract).