Limits...
CNP-pGC-cGMP-PDE3-cAMP Signal Pathway Upregulated in Gastric Smooth Muscle of Diabetic Rats.

Cai YL, Zhang MH, Huang X, Jiang JZ, Piao LH, Jin Z, Xu WX - Gastroenterol Res Pract (2015)

Bottom Line: The results demonstrated that the inhibitory effect of CNP on the spontaneous contraction of gastric antral circular smooth muscle was potentiated in STZ-induced diabetic rat.The expression of PDE3 is downregulated while the levels of gene expression of PDE1, PDE2, PDE4, and PDE5 were not altered in the diabetic gastric smooth muscle tissue.The results suggest that the sensitivity of gastric smooth muscle to CNP is potentiated via activation of CNP-pGC-cGMP-PDE3-cAMP signal pathway in STZ-induced diabetic rats, which may be associated with diabetes-induced gastric motility disorder.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Yanbian University School of Medicine, 977 Gongyuan Road, Yanji, Jilin 133002, China.

ABSTRACT
Our previous studies have shown that CNP-NPR-B/pGC-cGMP is upregulated in the diabetic rats. The present study was designed to determine whether the upregulation of CNP-NPR-B/pGC-cGMP signal pathway affects cGMP-PDE3-cAMP signal pathway in diabetic gastric smooth muscle. The gastric smooth muscle motility was observed by using isometric measurement. PDEs expressions in diabetic gastric smooth muscle tissue were observed by using immunohistochemistry, Western blotting, and RT-PCR methods. The results demonstrated that the inhibitory effect of CNP on the spontaneous contraction of gastric antral circular smooth muscle was potentiated in STZ-induced diabetic rat. CNP-induced increase of cGMP and cAMP was much higher in diabetic gastric smooth muscle tissue than in controls. The expression of PDE3 is downregulated while the levels of gene expression of PDE1, PDE2, PDE4, and PDE5 were not altered in the diabetic gastric smooth muscle tissue. The results suggest that the sensitivity of gastric smooth muscle to CNP is potentiated via activation of CNP-pGC-cGMP-PDE3-cAMP signal pathway in STZ-induced diabetic rats, which may be associated with diabetes-induced gastric motility disorder.

No MeSH data available.


Related in: MedlinePlus

Expression of PDE2 in the gastric smooth muscle. (a) PDE2 immunoreactivity in gastric smooth muscle was not different between the diabetic rats and controls (bars = 20 μm). (b) The mRNA level of PDE2 in the gastric smooth muscle was not different between diabetic rats and controls (n = 9, P > 0.05). (c) The protein level of PDE2 detected by Western blotting analysis in the gastric smooth muscle was not significantly different between diabetic rats and controls (n = 9, P > 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4390109&req=5

fig3: Expression of PDE2 in the gastric smooth muscle. (a) PDE2 immunoreactivity in gastric smooth muscle was not different between the diabetic rats and controls (bars = 20 μm). (b) The mRNA level of PDE2 in the gastric smooth muscle was not different between diabetic rats and controls (n = 9, P > 0.05). (c) The protein level of PDE2 detected by Western blotting analysis in the gastric smooth muscle was not significantly different between diabetic rats and controls (n = 9, P > 0.05).

Mentions: The cellular levels of the cyclic nucleotides reflect a balance between their synthesis and catabolism, and the latter was regulated by the enzymes of phosphodiesterase (PDE) family. Our previous study has shown that the generation of cAMP induced by CNP is via CNP-cGMP-PDE3-cAMP signal pathway in control rats [9]. Since the CNP-induced productions of cGMP and cAMP in gastric smooth muscle were significantly potentiated in diabetic rats, we were wondering whether the expression of PDE was changed in the diabetic rats. Firstly, we observed the expressions of PDE2 and PDE3 in the gastric smooth muscle of both control and diabetic rats by using immunohistochemistry technique, RT-PCR, and Western blotting methods. We found that the expression of PDE2 was not significantly different between the two groups. The PDE2 immunoreactive staining of gastric smooth muscle tissue was not different between control and diabetic rats (Figure 3(a)). The relative PDE2 mRNA levels (PDE2/GAPDH) were 0.65 ± 0.12 and 0.63 ± 0.46 in the control and diabetic rats, respectively (Figure 3(b), n = 9, P > 0.05). At the protein level, the ratios of PDE2/β-actin were 1.04 ± 0.07 in control and 1.10 ± 0.02 in diabetic rats (Figure 3(c), n = 9, P > 0.05). However, PDE3 expression was lower in the diabetic group than in the control group (Figure 4(a)). At the gene level, the ratios of PDE3/GAPDH were 1.25 ± 0.13 and 0.61 ± 0.11 in control and diabetic rats, respectively (Figure 4(b), n = 9, P < 0.05), and at the protein level, the ratios of PDE3/β-actin were 1.19  ±  0.11 and 0.43 ± 0.05 in control and diabetic rats, respectively (Figure 4(c), n = 9, P < 0.05). To further determine whether the expressions of other PDEs were changed in diabetic rat stomach, we also observed the expressions of PDE1, PDE4, and PDE5 in the gastric smooth muscle of both normal and diabetic rats. The results demonstrated that the mRNA levels of PDE1, PDE4, and PDE5 were not changed in diabetic rat stomach. The ratios of PDE2/GAPDH were 0.91   ± 0.47, 0.81 ± 0.41, and 0.72 ± 0.07 in control rats, respectively, and 0.88 ± 0.45, 0.90 ± 0.52, and 0.77 ± 0.09 in diabetic rats, respectively (Figure 5, n = 9, P > 0.05). These results suggest that only the expression of PDE3 was downregulated in gastric smooth muscle tissues of diabetic rats.


CNP-pGC-cGMP-PDE3-cAMP Signal Pathway Upregulated in Gastric Smooth Muscle of Diabetic Rats.

Cai YL, Zhang MH, Huang X, Jiang JZ, Piao LH, Jin Z, Xu WX - Gastroenterol Res Pract (2015)

Expression of PDE2 in the gastric smooth muscle. (a) PDE2 immunoreactivity in gastric smooth muscle was not different between the diabetic rats and controls (bars = 20 μm). (b) The mRNA level of PDE2 in the gastric smooth muscle was not different between diabetic rats and controls (n = 9, P > 0.05). (c) The protein level of PDE2 detected by Western blotting analysis in the gastric smooth muscle was not significantly different between diabetic rats and controls (n = 9, P > 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4390109&req=5

fig3: Expression of PDE2 in the gastric smooth muscle. (a) PDE2 immunoreactivity in gastric smooth muscle was not different between the diabetic rats and controls (bars = 20 μm). (b) The mRNA level of PDE2 in the gastric smooth muscle was not different between diabetic rats and controls (n = 9, P > 0.05). (c) The protein level of PDE2 detected by Western blotting analysis in the gastric smooth muscle was not significantly different between diabetic rats and controls (n = 9, P > 0.05).
Mentions: The cellular levels of the cyclic nucleotides reflect a balance between their synthesis and catabolism, and the latter was regulated by the enzymes of phosphodiesterase (PDE) family. Our previous study has shown that the generation of cAMP induced by CNP is via CNP-cGMP-PDE3-cAMP signal pathway in control rats [9]. Since the CNP-induced productions of cGMP and cAMP in gastric smooth muscle were significantly potentiated in diabetic rats, we were wondering whether the expression of PDE was changed in the diabetic rats. Firstly, we observed the expressions of PDE2 and PDE3 in the gastric smooth muscle of both control and diabetic rats by using immunohistochemistry technique, RT-PCR, and Western blotting methods. We found that the expression of PDE2 was not significantly different between the two groups. The PDE2 immunoreactive staining of gastric smooth muscle tissue was not different between control and diabetic rats (Figure 3(a)). The relative PDE2 mRNA levels (PDE2/GAPDH) were 0.65 ± 0.12 and 0.63 ± 0.46 in the control and diabetic rats, respectively (Figure 3(b), n = 9, P > 0.05). At the protein level, the ratios of PDE2/β-actin were 1.04 ± 0.07 in control and 1.10 ± 0.02 in diabetic rats (Figure 3(c), n = 9, P > 0.05). However, PDE3 expression was lower in the diabetic group than in the control group (Figure 4(a)). At the gene level, the ratios of PDE3/GAPDH were 1.25 ± 0.13 and 0.61 ± 0.11 in control and diabetic rats, respectively (Figure 4(b), n = 9, P < 0.05), and at the protein level, the ratios of PDE3/β-actin were 1.19  ±  0.11 and 0.43 ± 0.05 in control and diabetic rats, respectively (Figure 4(c), n = 9, P < 0.05). To further determine whether the expressions of other PDEs were changed in diabetic rat stomach, we also observed the expressions of PDE1, PDE4, and PDE5 in the gastric smooth muscle of both normal and diabetic rats. The results demonstrated that the mRNA levels of PDE1, PDE4, and PDE5 were not changed in diabetic rat stomach. The ratios of PDE2/GAPDH were 0.91   ± 0.47, 0.81 ± 0.41, and 0.72 ± 0.07 in control rats, respectively, and 0.88 ± 0.45, 0.90 ± 0.52, and 0.77 ± 0.09 in diabetic rats, respectively (Figure 5, n = 9, P > 0.05). These results suggest that only the expression of PDE3 was downregulated in gastric smooth muscle tissues of diabetic rats.

Bottom Line: The results demonstrated that the inhibitory effect of CNP on the spontaneous contraction of gastric antral circular smooth muscle was potentiated in STZ-induced diabetic rat.The expression of PDE3 is downregulated while the levels of gene expression of PDE1, PDE2, PDE4, and PDE5 were not altered in the diabetic gastric smooth muscle tissue.The results suggest that the sensitivity of gastric smooth muscle to CNP is potentiated via activation of CNP-pGC-cGMP-PDE3-cAMP signal pathway in STZ-induced diabetic rats, which may be associated with diabetes-induced gastric motility disorder.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Yanbian University School of Medicine, 977 Gongyuan Road, Yanji, Jilin 133002, China.

ABSTRACT
Our previous studies have shown that CNP-NPR-B/pGC-cGMP is upregulated in the diabetic rats. The present study was designed to determine whether the upregulation of CNP-NPR-B/pGC-cGMP signal pathway affects cGMP-PDE3-cAMP signal pathway in diabetic gastric smooth muscle. The gastric smooth muscle motility was observed by using isometric measurement. PDEs expressions in diabetic gastric smooth muscle tissue were observed by using immunohistochemistry, Western blotting, and RT-PCR methods. The results demonstrated that the inhibitory effect of CNP on the spontaneous contraction of gastric antral circular smooth muscle was potentiated in STZ-induced diabetic rat. CNP-induced increase of cGMP and cAMP was much higher in diabetic gastric smooth muscle tissue than in controls. The expression of PDE3 is downregulated while the levels of gene expression of PDE1, PDE2, PDE4, and PDE5 were not altered in the diabetic gastric smooth muscle tissue. The results suggest that the sensitivity of gastric smooth muscle to CNP is potentiated via activation of CNP-pGC-cGMP-PDE3-cAMP signal pathway in STZ-induced diabetic rats, which may be associated with diabetes-induced gastric motility disorder.

No MeSH data available.


Related in: MedlinePlus