HO-CO pathway activation may be associated with hippocampal μ and δ opioid on receptors in inhibiting inflammatory pain aversiveness and nociception in WT but not NOS2-KO mice.

HO-CO pathway activation may be associated with hippocampal μ and δ opioid on receptors in inhibiting inflammatory pain aversiveness and nociception in WT but not NOS2-KO mice. Brain Res Bull. 2021 Jan 07;: Authors: Cazuza RA, Arantes ALF, Pol O, Leite-Panissi CRA Abstract Carbon monoxide (CO) and nitric oxide (NO) modulate inflammatory nociception and anxiety. We evaluate whether treatments with a heme oxygenase-1 (HO-1) inducer (CoPP) or a carbon monoxide-releasing molecule (CORM-2) are capable of inhibiting inflammatory pain aversiveness in wild type (WT) and inducible nitric oxide synthase-knock out (NOS2-KO) mice with persistent inflammation and its relationship with μ- (MOR) and δ- (DOR) opioid receptors. WT and NOS2-KO male mice with complete Freund's adjuvant (CFA) injected into the hind paw were evaluated in the von Frey and the escape-avoidance paradigm (PEAP) tests, at 10 days, before and after the treatment with CORM-2 (5 mg/kg) or CoPP (2.5 mg/kg). WT mice groups treated with CORM-2 or CoPP also received naloxone (NLX, a non-specific opioid receptor antagonist). The HO-1, neuronal nitric oxide synthase, NOS2, MOR, and DOR expression in the dorsal hippocampus were evaluated by western blot. CFA reduced mechanical threshold in WT and NOS2-KO mice but only increased the percentage of time in the light compartment in the PEAP in WT mice. CORM-2 and CoPP inhibited these effects in both strains. Pre-treatment with NLX ...
Source: Brain Research Bulletin - Category: Neurology Authors: Tags: Brain Res Bull Source Type: research