Publications by authors named "Masafumi Yokai"
Article Synopsis
- PACAP and its receptors, found in the spinal dorsal horn and dorsal root ganglia, play a significant role in the modulation of pain transmission and may influence chronic pain conditions.
- Research indicates that PACAP and selective PAC1 receptor agonists can lead to mechanical allodynia, highlighting the potential for PAC1 antagonists as new pain relief treatments.
- The study successfully identified two new small-molecule PAC1 antagonists, PA-8 and PA-9, which effectively inhibit PACAP-induced responses in mice and show promise for future analgesic development without causing adverse effects on their own.
Article Synopsis
- The study introduces a rare form of Guillain-Barré syndrome involving small-fiber neuropathy, marked by prior infections, low reflexes, and specific changes in spinal fluid.
- Two patients were treated with either intravenous immunoglobulin or corticosteroids and showed improvement in their condition.
- The findings indicate that the immune system may temporarily target small nerve fibers, leading to symptoms similar to Guillain-Barré syndrome, as evidenced by specific antibody behavior and experimental models.
Background: Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors are present in the spinal dorsal horn and dorsal root ganglia, suggesting an important role of PACAP-PACAP receptors signaling system in the modulation of spinal nociceptive transmission. We have previously reported that a single intrathecal injection of PACAP or a PACAP specific (PAC1) receptor selective agonist, maxadilan, in mice induced dose-dependent aversive behaviors, which lasted more than 30 min, and suggested that the maintenance of the nociceptive behaviors was associated with the spinal astrocytic activation.
Results: We found that a single intrathecal administration of PACAP or maxadilan also produced long-lasting hind paw mechanical allodynia, which persisted at least 84 days without affecting thermal nociceptive threshold.
Intrathecal (i.t.) administration of pituitary adenylate cyclase-activating polypeptide (PACAP) induces long-lasting nociceptive behaviors for more than 60 min in mice, while the involvement of PACAP type1 receptor (PAC1-R) has not been clarified yet.
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