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P2X3 receptors mediate visceral hypersensitivity during acute chemically-induced colitis and in the post-inflammatory phase via different mechanisms of sensitization.

Deiteren A, van der Linden L, de Wit A, Ceuleers H, Buckinx R, Timmermans JP, Moreels TG, Pelckmans PA, De Man JG, De Winter BY - PLoS ONE (2015)

Bottom Line: Hypersenstivity was accompanied by an increased colonic release of ATP.A-317491 did not modify visceral sensitivity in controls.These findings indicate that P2X3 receptors are not involved in sensory signaling under physiological conditions whereas they modulate visceral hypersensitivity during acute TNBS-colitis and even more so in the post-inflammatory phase, albeit via different mechanisms of sensitization, validating P2X3 receptors as potential new targets in the treatment of abdominal pain syndromes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium.

ABSTRACT

Objectives: Experiments using P2X3 knock-out mice or more general P2X receptor antagonists suggest that P2X3 receptors contribute to visceral hypersensitivity. We aimed to investigate the effect of the selective P2X3 antagonist A-317491 on visceral sensitivity under physiological conditions, during acute colitis and in the post-inflammatory phase of colitis.

Methods: Trinitrobenzene sulphonic-acid colitis was monitored by colonoscopy: on day 3 to confirm the presence of colitis and then every 4 days, starting from day 10, to monitor convalescence and determine the exact timepoint of endoscopic healing in each rat. Visceral sensitivity was assessed by quantifying visceromotor responses to colorectal distension in controls, rats with acute colitis and post-colitis rats. A-317491 was administered 30 min prior to visceral sensitivity testing. Expression of P2X3 receptors (RT-PCR and immunohistochemistry) and the intracellular signalling molecules cdk5, csk and CASK (RT-PCR) were quantified in colonic tissue and dorsal root ganglia. ATP release in response to colorectal distension was measured by luminiscence.

Results: Rats with acute TNBS-colitis displayed significant visceral hypersensitivity that was dose-dependently, but not fully, reversed by A-317491. Hypersenstivity was accompanied by an increased colonic release of ATP. Post-colitis rats also displayed visceral hypersensitivity that was dose-dependently reduced and fully normalized by A-317491 without increased release of ATP. A-317491 did not modify visceral sensitivity in controls. P2X3 mRNA and protein expression in the colon and dorsal root ganglia were similar in control, acute colitis and post-colitis groups, while colonic mRNA expression of cdk5, csk and CASK was increased in the post-colitis group only.

Conclusions: These findings indicate that P2X3 receptors are not involved in sensory signaling under physiological conditions whereas they modulate visceral hypersensitivity during acute TNBS-colitis and even more so in the post-inflammatory phase, albeit via different mechanisms of sensitization, validating P2X3 receptors as potential new targets in the treatment of abdominal pain syndromes.

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Effect of A-314791 on VMRs and colonic compliance during acute TNBS-colitis.VMRs were assessed 3 days post-TNBS enema, immediately followed by an evaluation of colonic compliance. A-314791 (filled symbols; 10–25 mg/kg) or vehicle (open symbols) was administered 30 min prior to VMR assessment. Increased VMRs were present in rats with acute TNBS-colitis compared to controls and were dose-dependently reduced by 10 mg/kg (A) and 25 mg/kg (B) A-317491. The 25 mg/kg dose did not affect VMRs in healthy controls (C). To facilitate comparison, VMRs for vehicle-treated control rats are also shown in A and B (gray dashed line). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, ** p<0.01, *** p<0.001, significantly different from control + vehicle; # p<0.05, ## p<0.01, ### p<0.001, significantly different from acute colitis + vehicle. Colonic compliance was reduced during acute TNBS-colitis, but remained unaffected by A-317491 (10–25 mg/kg) (D). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, significant effect of the factor colitis.
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pone.0123810.g002: Effect of A-314791 on VMRs and colonic compliance during acute TNBS-colitis.VMRs were assessed 3 days post-TNBS enema, immediately followed by an evaluation of colonic compliance. A-314791 (filled symbols; 10–25 mg/kg) or vehicle (open symbols) was administered 30 min prior to VMR assessment. Increased VMRs were present in rats with acute TNBS-colitis compared to controls and were dose-dependently reduced by 10 mg/kg (A) and 25 mg/kg (B) A-317491. The 25 mg/kg dose did not affect VMRs in healthy controls (C). To facilitate comparison, VMRs for vehicle-treated control rats are also shown in A and B (gray dashed line). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, ** p<0.01, *** p<0.001, significantly different from control + vehicle; # p<0.05, ## p<0.01, ### p<0.001, significantly different from acute colitis + vehicle. Colonic compliance was reduced during acute TNBS-colitis, but remained unaffected by A-317491 (10–25 mg/kg) (D). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, significant effect of the factor colitis.

Mentions: VMRs to colorectal distension were markedly increased during acute TNBS-colitis compared to controls, indicating the presence of acute inflammation-induced visceral hypersensitivity (Fig 2A). This hypersensitivity was dose-dependently reduced by A-317491. After 10 mg/kg of A-317491 VMRs were not significantly reduced at the highest distension pressures of 40–80 mmHg but were markedly attenuated at the lower distension pressures (20 and 30 mmHg). In contrast, 25 mg/kg significantly reduced hypersensitivity for almost the full range of distension pressures (20 to 80 mmHg) (Fig 2B). However, VMRs remained significantly increased compared to controls at 10 to 30 mmHg distension. The 25 mg/kg dose did not affect VMRs in the control group (Fig 2C).


P2X3 receptors mediate visceral hypersensitivity during acute chemically-induced colitis and in the post-inflammatory phase via different mechanisms of sensitization.

Deiteren A, van der Linden L, de Wit A, Ceuleers H, Buckinx R, Timmermans JP, Moreels TG, Pelckmans PA, De Man JG, De Winter BY - PLoS ONE (2015)

Effect of A-314791 on VMRs and colonic compliance during acute TNBS-colitis.VMRs were assessed 3 days post-TNBS enema, immediately followed by an evaluation of colonic compliance. A-314791 (filled symbols; 10–25 mg/kg) or vehicle (open symbols) was administered 30 min prior to VMR assessment. Increased VMRs were present in rats with acute TNBS-colitis compared to controls and were dose-dependently reduced by 10 mg/kg (A) and 25 mg/kg (B) A-317491. The 25 mg/kg dose did not affect VMRs in healthy controls (C). To facilitate comparison, VMRs for vehicle-treated control rats are also shown in A and B (gray dashed line). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, ** p<0.01, *** p<0.001, significantly different from control + vehicle; # p<0.05, ## p<0.01, ### p<0.001, significantly different from acute colitis + vehicle. Colonic compliance was reduced during acute TNBS-colitis, but remained unaffected by A-317491 (10–25 mg/kg) (D). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, significant effect of the factor colitis.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4401691&req=5

pone.0123810.g002: Effect of A-314791 on VMRs and colonic compliance during acute TNBS-colitis.VMRs were assessed 3 days post-TNBS enema, immediately followed by an evaluation of colonic compliance. A-314791 (filled symbols; 10–25 mg/kg) or vehicle (open symbols) was administered 30 min prior to VMR assessment. Increased VMRs were present in rats with acute TNBS-colitis compared to controls and were dose-dependently reduced by 10 mg/kg (A) and 25 mg/kg (B) A-317491. The 25 mg/kg dose did not affect VMRs in healthy controls (C). To facilitate comparison, VMRs for vehicle-treated control rats are also shown in A and B (gray dashed line). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, ** p<0.01, *** p<0.001, significantly different from control + vehicle; # p<0.05, ## p<0.01, ### p<0.001, significantly different from acute colitis + vehicle. Colonic compliance was reduced during acute TNBS-colitis, but remained unaffected by A-317491 (10–25 mg/kg) (D). Generalized estimating equations, LSD post-hoc test, n = 5–8; * p<0.05, significant effect of the factor colitis.
Mentions: VMRs to colorectal distension were markedly increased during acute TNBS-colitis compared to controls, indicating the presence of acute inflammation-induced visceral hypersensitivity (Fig 2A). This hypersensitivity was dose-dependently reduced by A-317491. After 10 mg/kg of A-317491 VMRs were not significantly reduced at the highest distension pressures of 40–80 mmHg but were markedly attenuated at the lower distension pressures (20 and 30 mmHg). In contrast, 25 mg/kg significantly reduced hypersensitivity for almost the full range of distension pressures (20 to 80 mmHg) (Fig 2B). However, VMRs remained significantly increased compared to controls at 10 to 30 mmHg distension. The 25 mg/kg dose did not affect VMRs in the control group (Fig 2C).

Bottom Line: Hypersenstivity was accompanied by an increased colonic release of ATP.A-317491 did not modify visceral sensitivity in controls.These findings indicate that P2X3 receptors are not involved in sensory signaling under physiological conditions whereas they modulate visceral hypersensitivity during acute TNBS-colitis and even more so in the post-inflammatory phase, albeit via different mechanisms of sensitization, validating P2X3 receptors as potential new targets in the treatment of abdominal pain syndromes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium.

ABSTRACT

Objectives: Experiments using P2X3 knock-out mice or more general P2X receptor antagonists suggest that P2X3 receptors contribute to visceral hypersensitivity. We aimed to investigate the effect of the selective P2X3 antagonist A-317491 on visceral sensitivity under physiological conditions, during acute colitis and in the post-inflammatory phase of colitis.

Methods: Trinitrobenzene sulphonic-acid colitis was monitored by colonoscopy: on day 3 to confirm the presence of colitis and then every 4 days, starting from day 10, to monitor convalescence and determine the exact timepoint of endoscopic healing in each rat. Visceral sensitivity was assessed by quantifying visceromotor responses to colorectal distension in controls, rats with acute colitis and post-colitis rats. A-317491 was administered 30 min prior to visceral sensitivity testing. Expression of P2X3 receptors (RT-PCR and immunohistochemistry) and the intracellular signalling molecules cdk5, csk and CASK (RT-PCR) were quantified in colonic tissue and dorsal root ganglia. ATP release in response to colorectal distension was measured by luminiscence.

Results: Rats with acute TNBS-colitis displayed significant visceral hypersensitivity that was dose-dependently, but not fully, reversed by A-317491. Hypersenstivity was accompanied by an increased colonic release of ATP. Post-colitis rats also displayed visceral hypersensitivity that was dose-dependently reduced and fully normalized by A-317491 without increased release of ATP. A-317491 did not modify visceral sensitivity in controls. P2X3 mRNA and protein expression in the colon and dorsal root ganglia were similar in control, acute colitis and post-colitis groups, while colonic mRNA expression of cdk5, csk and CASK was increased in the post-colitis group only.

Conclusions: These findings indicate that P2X3 receptors are not involved in sensory signaling under physiological conditions whereas they modulate visceral hypersensitivity during acute TNBS-colitis and even more so in the post-inflammatory phase, albeit via different mechanisms of sensitization, validating P2X3 receptors as potential new targets in the treatment of abdominal pain syndromes.

Show MeSH
Related in: MedlinePlus