Centrally mediated antinociceptive effects of cannabinoid receptor ligands in rat models of nociception

► CB receptor agonist WIN 55,212-2 was effective in the hot plate and formalin tests. ► Hemopressin (HE) was effective in the formalin test but not in the hot plate test. ► High doses of HE lead to increased pain-related behaviors in the formalin test. ► The results suggest a differential efficacy of HE depending on pain state.