Anxiolytic- and antidepressant-like effects of angiotensin-(1-7) in hypertensive transgenic (mRen2)27 rats

Angiotensin-(1-7) [Ang-(1-7)], a counter-regulatory peptide of the renin-angiotensin system (RAS) exerts its effects through the G-protein-coupled receptor Mas, which is expressed in different tissues, including the brain.  Ang-(1-7) has a broad range of effects beyond the well-described cardiovascular and renal actions, including the modulation of emotional and behavioral responses.  In the present study we tested the hypothesis that Ang-(1-7) could attenuate the anxiety- and depressive-like behaviors observed in transgenic hypertensive (mRen2)27 (TGR) rats.  We also hypothesized that Ang-(1-7) could be involved in the anxiolytic-like effect induced by ACE treatment in these hypertensive rats.  Therefore, TGR and SD rats were subjected to the Elevated Plus Maze test (EPM), Forced Swimming test (FST) and the Novelty Suppressed Feeding (NSF).  TGR rats presented a decreased percentage of entries in the open arms of the EPM, a phenotype reversed by systemic treatment with enalapril or ICV infusion of Ang-(1-7).  Interestingly, pre-treatment with A779, a selective Mas receptor antagonist, prevented the anxiolytic-like effect induced by the ACE inhibitor.  In the NSF test, TGRs showed increased latency to eat, indicative of higher aversive response to a new environment.  These animals also showed increased immobility in FST.  Again, Ang-(1-7) reversed this phenotype.  Thus, our data showed that Ang-(1-7) can modulate anx...
Source: Clinical Science - Category: Biomedical Science Authors: Tags: PublishAheadOfPrint Source Type: research