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The angiotensin II receptor type 2 agonist CGP 42112A stimulates NO production in the porcine jejunal mucosa.

Ewert S, Laesser M, Johansson B, Holm M, Aneman A, Fandriks L - BMC Pharmacol. (2003)

Bottom Line: Baseline luminal NO output correlated significantly to baseline mucosal iNOS-protein content.No differences in iNOS protein expression were found between groups or before/after the administration of drugs.The results suggest that activation of AT2 receptors increases jejunal luminal NO output.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Gastrosurgical Research, Sahlgrenska Academy, Goteborg University, Sweden. sara.ewert@gastro.gu.se

ABSTRACT

Background: This study was conducted to elucidate if nitric oxide is released by the porcine jejunal mucosa upon selective stimulation of AT2 receptors and the possible involvement of iNOS, and to investigate the presence of jejunal AT1 and AT2 receptors. Young landrace pigs were anaesthetized with ketamine and alpha-chloralose. Jejunal luminal NO output was assessed by intraluminal tonometry and analysed by chemiluminescense. Western blot analysis quantified mucosal iNOS and detected AT1 and AT2 receptor protein expression. AT1 and AT2 receptor RNA expression was detected by rtPCR.

Results: Baseline luminal NO output correlated significantly to baseline mucosal iNOS-protein content. In animals treated with the AT2-receptor agonist CGP42112A (n = 11) luminal NO output increased significantly (at 0.1 micrograms kg(-1) min(-1) and 1.0 micrograms kg(-1) min(-1)), but not in animals simultaneously treated with the AT2-receptor antagonist PD123319 (bolus 0.3 mgkg-1, infusion 0.03 mg kg(-1) h(-1)) (n = 7). No differences in iNOS protein expression were found between groups or before/after the administration of drugs. Western blot and rtPCR recognised expression of the AT1 and AT2 receptors in jejunal tissue.

Conclusion: The results suggest that activation of AT2 receptors increases jejunal luminal NO output. This response was not due to an increase in the expression of the iNOS protein in the mucosa.

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Western blot experiments using specific antibodies to AT1 and AT2 receptors, respectively. Staining for AT1 receptor detect a single band at the size 41 kDa in all individuals (n = 11) and the PC12 cell lysate serving as a positive control. Staining for AT2 receptor detect a single band at the size 44 kDa in all individuals (n = 11) and in the KNRK cell lysate serving as a positive control.
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Figure 3: Western blot experiments using specific antibodies to AT1 and AT2 receptors, respectively. Staining for AT1 receptor detect a single band at the size 41 kDa in all individuals (n = 11) and the PC12 cell lysate serving as a positive control. Staining for AT2 receptor detect a single band at the size 44 kDa in all individuals (n = 11) and in the KNRK cell lysate serving as a positive control.

Mentions: Western blot using antibodies specific for AT1 and AT2 receptor proteins recognised bands of the expected molecular weight 41 kDa and 44 kDa, respectively, in all samples (n = 11) (Figure 3).


The angiotensin II receptor type 2 agonist CGP 42112A stimulates NO production in the porcine jejunal mucosa.

Ewert S, Laesser M, Johansson B, Holm M, Aneman A, Fandriks L - BMC Pharmacol. (2003)

Western blot experiments using specific antibodies to AT1 and AT2 receptors, respectively. Staining for AT1 receptor detect a single band at the size 41 kDa in all individuals (n = 11) and the PC12 cell lysate serving as a positive control. Staining for AT2 receptor detect a single band at the size 44 kDa in all individuals (n = 11) and in the KNRK cell lysate serving as a positive control.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC153509&req=5

Figure 3: Western blot experiments using specific antibodies to AT1 and AT2 receptors, respectively. Staining for AT1 receptor detect a single band at the size 41 kDa in all individuals (n = 11) and the PC12 cell lysate serving as a positive control. Staining for AT2 receptor detect a single band at the size 44 kDa in all individuals (n = 11) and in the KNRK cell lysate serving as a positive control.
Mentions: Western blot using antibodies specific for AT1 and AT2 receptor proteins recognised bands of the expected molecular weight 41 kDa and 44 kDa, respectively, in all samples (n = 11) (Figure 3).

Bottom Line: Baseline luminal NO output correlated significantly to baseline mucosal iNOS-protein content.No differences in iNOS protein expression were found between groups or before/after the administration of drugs.The results suggest that activation of AT2 receptors increases jejunal luminal NO output.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Gastrosurgical Research, Sahlgrenska Academy, Goteborg University, Sweden. sara.ewert@gastro.gu.se

ABSTRACT

Background: This study was conducted to elucidate if nitric oxide is released by the porcine jejunal mucosa upon selective stimulation of AT2 receptors and the possible involvement of iNOS, and to investigate the presence of jejunal AT1 and AT2 receptors. Young landrace pigs were anaesthetized with ketamine and alpha-chloralose. Jejunal luminal NO output was assessed by intraluminal tonometry and analysed by chemiluminescense. Western blot analysis quantified mucosal iNOS and detected AT1 and AT2 receptor protein expression. AT1 and AT2 receptor RNA expression was detected by rtPCR.

Results: Baseline luminal NO output correlated significantly to baseline mucosal iNOS-protein content. In animals treated with the AT2-receptor agonist CGP42112A (n = 11) luminal NO output increased significantly (at 0.1 micrograms kg(-1) min(-1) and 1.0 micrograms kg(-1) min(-1)), but not in animals simultaneously treated with the AT2-receptor antagonist PD123319 (bolus 0.3 mgkg-1, infusion 0.03 mg kg(-1) h(-1)) (n = 7). No differences in iNOS protein expression were found between groups or before/after the administration of drugs. Western blot and rtPCR recognised expression of the AT1 and AT2 receptors in jejunal tissue.

Conclusion: The results suggest that activation of AT2 receptors increases jejunal luminal NO output. This response was not due to an increase in the expression of the iNOS protein in the mucosa.

Show MeSH