Antinociceptive effects of novel melatonin receptor agonists in mouse models of abdominal pain.
World J Gastroenterol 2014;
20:1298-1304. [PMID:
24574803 PMCID:
PMC3921511 DOI:
10.3748/wjg.v20.i5.1298]
[Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/10/2013] [Accepted: 11/05/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To characterize the antinociceptive action of the novel melatonin receptor (MT) agonists, Neu-P11 and Neu-P12 in animal models of visceral pain.
METHODS: Visceral pain was induced by intracolonic (ic) application of mustard oil or capsaicin solution or by intraperitoneal (ip) administration of acetic acid. Neu-P11, Neu-P12, or melatonin were given ip or orally and their effects on pain-induced behavioral responses were evaluated. To identify the receptors involved, the non-selective MT1/MT2 receptor antagonist luzindole, the MT2 receptor antagonist 4-P-PDOT, or the μ-opioid receptor antagonist naloxone were injected ip or intracerebroventricularly (icv) prior to the induction of pain.
RESULTS: Orally and ip administered melatonin, Neu-P11, and Neu-P12 reduced pain responses in a dose-dependent manner. Neu-P12 was more effective and displayed longer duration of action compared to melatonin. The antinociceptive effects of Neu-P11 or Neu-P12 were antagonized by ip or icv. administered naloxone. Intracerebroventricularly, but not ip administration of luzindole or 4-P-PDOT blocked the antinociceptive actions of Neu-P11 or Neu-P12.
CONCLUSION: Neu-P12 produced the most potent and long-lasting antinociceptive effect. Further development of Neu-P12 for future treatment of abdominal pain seems promising.
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