Histamine H₁ receptors regulate anhedonic-like behavior in rats: Involvement of the anterior cingulate and lateral...

A decreased H₁ receptor activity is observed in the anterior cingulate cortex (aCgCx) of depressed patients. The role of this abnormality in the development of depression-related processes is unstudied. We examined the influence of a decreased brain H₁ receptor activity on rat behavior in the sucrose preference test. The H₁ receptor deficit was simulated by injection of an H₁ antagonist into the aCgCx; also, two aCgCx projection areas, lateral and medial entorhinal cortices were examined. A blockade of H₁-receptors in the aCgCx and lateral entorhinal cortex (LEntCx) significantly reduced sucrose preference. These findings suggest the existence of H₁ receptor-mediated aCgCx-LEntCx circuitry mechanism regulating anhedonic-like behavior in rats. The presented data suggest that H₁ receptor-mediated processes might be a therapeutic target in depressive disorders.