Interferon-γ receptors in nociceptive pathways

Abstract

INTERFERON-γ receptor (IFN-γR) immunoreactivity was observed in the superficial dorsal horn and lateral spinal nucleus in rat and mouse spinal cord. Dorsal rhizotomies did not reduce immunoreactivity in the rat. IFN-γ distribution overlapped with nitric oxide synthase-1 immunoreactivity. In wild-type mice, intrathecal injections of mouse IFN-γ evoked biting behaviour, whereas mice with disruption of the functional gene for IFN-γR did not respond. Both types of mice had similar withdrawal thresholds to mechanical stimulation and reacted similarly to foot-pad carrageenan injections. In contrast to wild-type mice, IFN-γR knock-out mice did not show autotomy after sciatic nerve section. This study demonstrates a functional IFN-γR in spinal nociceptive pathways related to neuropathic pain.