Flexor reflex excitability in mice lacking galanin receptor galanin-R1

• Published in: Neuroscience letters 2003-07, Vol.345 (3), p.153-156
• Main Authors: Grass, Stefan, Jacoby, Arie S, Iismaa, Tiina P, Crawley, Jacqueline N, Xu, Xiao-Jun, Wiesenfeld-Hallin, Zsuzsanna
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animals; Biological and medical sciences; Central sensitization; Dose-Response Relationship, Drug; Electric Stimulation; Electromyography - methods; Fundamental and applied biological sciences. Psychology; Galanin - pharmacology; Intrathecal; Knockout; Medicin och hälsovetenskap; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscles - drug effects; Muscles - physiology; Nerve Fibers - physiology; Neural Inhibition - drug effects; Neural Inhibition - physiology; Nociception; Pain; Receptors, Galanin; Receptors, Neuropeptide - deficiency; Receptors, Neuropeptide - genetics; Receptors, Neuropeptide - metabolism; Reflex - physiology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Spinal cord; Sural Nerve - physiology; Vertebrates: nervous system and sense organs; Wind-up
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(03)00516-0

This study was conducted to examine the excitability of the nociceptive flexor reflex and its sensitization by repetitive stimulation of C-fibers in anesthetized mice that lack the galanin-R1 receptor. Repetitive stimulation of C-fibers induced a gradual increase in reflex magnitude during the stimulation (wind-up), and a subsequent increase in spinal reflex excitability (central sensitization). This occurred in GAL-R1 −/−, GAL-R1 +/−, and +/+ wild-type controls, with no significant differences observed between genotypes. Intrathecal administration of galanin markedly blocked the sensitization following the repetitive stimulation in all three groups. No differences between wild-type or galanin-R1 receptor knockout mice were seen. These results confirm previous studies in rats, showing that intrathecal galanin reduces the central sensitization following wind-up. The present data indicate that this effect is probably mediated by receptors other than GAL-R1.