Neuroprotective Effects of Nicorandil in Chronic Cerebral Hypoperfusion-Induced Vascular Dementia

Background: Ischemia-induced chronic cerebral hypoperfusion (CCH) is associated with reduced cerebral blood flow and vascular dementia (VaD). Brain mitochondrial potassium (adenosine triphosphate-sensitive potassium [KATP]) channels have a beneficial role in various brain conditions. The utility of KATP channels in CCH-induced VaD is still unknown. The aim of this study is to investigate the role of nicorandil, a selective KATP channel opener, in CCH-induced VaD. Methods: The method of 2-vessel occlusion (2VO) was used to induce CCH in mice. Cognitive impairment was assessed using Morris water maze. Serum nitrosative stress (nitrite/nitrate), brain cholinergic dysfunction (acetylcholinesterase [AChE] activity), brain oxidative stress (thiobarbituric acid reactive substances, glutathione [GSH], catalase [CAT], and superoxide dismutase [SOD]), inflammation (myeloperoxidase [MPO]), and infarct size (2,3,5-triphenyltetrazolium chloride staining) were assessed. Results: 2-vessels-occluded animals have shown significant cognitive impairment, serum nitrosative stress (reduced nitrite/nitrate), cholinergic dysfunction (increased brain AChE activity), and increased brain oxidative stress (reduction in GSH content and SOD and CAT activities with a significant increase in lipid peroxidation), along with a significant increase in MPO activity and infarct size. However, nicorandil treatment has significantly attenuated various CCH-induced behavioral and biochemical impairments. Conclusions: It may be said that 2VO provoked CCH leading to VaD, which was attenuated by the treatment of nicorandil. So, modulation of KATP channels may provide benefits in CCH-induced VaD.