Modulation of heme oxygenase/carbon monoxide system affects the inhibitory neurotransmission involved in gastrointestinal motility of streptozotocin‐treated diabetic rats

Alterations in gastrointestinal motility of diabetic patients have been linked to degenerative changes induced by glucose abnormalities in the peripheral nervous system. The heme oxygenase/carbon monoxide (HO/CO) signalling represents one of the non‐adrenergic/non‐cholinergic (NANC) neurotransmission pathways involved in regulation of physiological peristalsis. To investigate the role of HO/CO system in intestinal motility under diabetic conditions, the response to electrical field stimulation (EFS) and western blot analysis of HO/CO pathway components were studied on duodenum longitudinal smooth muscle strips isolated from streptozotocin (STZ)‐treated diabetic rats (65 mg kg−1, i.p.) and respective controls (CTRL), 6 weeks after the onset of diabetes. When compared to CTRL, the ability of CO releasing molecule (CORM‐3) (100–400 μmol L−1) to enhance NANC relaxation was significantly impaired in STZ‐treated rats (P