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  2. The novel small-molecule antagonist of PAC1 receptor attenuates formalin-induced inflammatory pain behaviors in mice

The novel small-molecule antagonist of PAC1 receptor attenuates formalin-induced inflammatory pain behaviors in mice

  • J Pharmacol Sci. 2019 Feb;139(2):129-132. doi: 10.1016/j.jphs.2018.11.011.
Ichiro Takasaki 1 Koji Nakamura 2 Ayaka Shimodaira 2 Ai Watanabe 2 Huy Du Nguyen 3 Takuya Okada 3 Naoki Toyooka 3 Atsuro Miyata 4 Takashi Kurihara 4
Affiliations

Affiliations

  • 1 Department of Pharmacology, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan; Graduate School of Innovative Life Sciences, University of Toyama, Toyama, Japan. Electronic address: takasaki@eng.u-toyama.ac.jp.
  • 2 Department of Pharmacology, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan.
  • 3 Graduate School of Innovative Life Sciences, University of Toyama, Toyama, Japan; Department of Bio-functional Molecular Engineering, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan.
  • 4 Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
Abstract

We recently developed PA-8, a novel small-molecule antagonist of PACAP type 1 (PAC1) receptor. In the present study, we examined whether PA-8 was effective against formalin-induced inflammatory pain in mice. Both intrathecal and oral administration of PA-8 resulted in the dose-dependent attenuation of the second phase of formalin-induced nociceptive responses. PA-8 also inhibited c-fos upregulation in the ipsilateral dorsal horn of the spinal cord. The results suggested that PACAP-PAC1 receptor signaling system in the spinal cord were primarily involved in the transmission of inflammatory pain, and PA-8 could be useful for the development of novel analgesics for treating inflammatory pain.

Keywords

Inflammatory pain; PACAP type 1 (PAC1) receptor; Small-molecule antagonist.

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