ATP-sensitive potassium-channel inhibitor glibenclamide attenuates HPA axis hyperactivity, depression- and anxiety-related symptoms in a rat model of Alzheimer's disease

Abstract

Affective disorders including depression and anxiety are among the most prevalent behavioral abnormalities in patients with Alzheimer's disease (AD), which affect the quality of life and progression of the disease. Dysregulation of the hypothalamic-pituitary-adrenal-(HPA) axis has been reported in affective disorders and AD. Recent studies revealed that current antidepressant drugs are not completely effective for treating anxiety- and depression-related disorders in people with dementia. ATP-sensitive-potassium-(K-ATP) channels are well-known to be involved in A beta pathophysiology, HPA axis function and the pathogenesis of depression and anxiety-related behaviors. Thus, targeting of K-ATP channel may be a potential therapeutic strategy in AD. Hence, we investigated the effects of intracerebroventricular injection of A beta 25-35 alone or in combination with glibenclamide, K-ATP channel inhibitor on depression- and anxiety-related behaviors as well as HPA axis response to stress in rats. To do this, non-A beta 25-35- and A beta 25-35-treated rats were orally treated with glibenclamide, then the behavioral con sequences were assessed using sucrose preference, forced swim, light-dark box and plus maze tests. Stress induced corticosterone levels following forced swim and plus maze tests were also evaluated as indicative of abnormal HPA-axis-function. A beta 25-35 induced HPA axis hyperreactivity and increased depression- and anxiety related symptoms in rats. Our results showed that blockade of K-ATP channels with glibenclamide decreased depression- and anxiety-related behaviors by normalizing HPA axis activity in A beta 25-35-treated rats. This study provides additional evidence that A beta administration can induce depression- and anxiety-like symptoms in rodents, and suggests that K-ATP channel inhibitors may be a plausible therapeutic strategy for treating affective disorders in A beta patients.