Polyphenol ellagic acid (EA) possesses anti-oxidant, anti-inflammatory, anti-carcinogenic, anti-diabetic and cardio protection activities, remarking it an interesting multi-targeting profile. EA also controls the central nervous system (CNS) since it was proven to reduce the immobility time of mice in both the forced swimming and the tail-suspension tests, with an efficiency comparable to that of classic antidepressants. Interestingly, the anti-depressant-like effect was almost nulled by the concomitant administration of selective antagonists of the noradrenergic receptors, suggesting the involvement of these cellular targets in the central effects elicited by EA and its derivatives. By in silico and in vitro studies, we discuss how EA engages with human α2A-ARs and α2C-AR catalytic pockets, comparing EA behaviour with those ones of known agonist and antagonist. Structurally, the hydrophobic residues surrounding α2A-AR pocket confer specificity on the intermolecular interactions and hence lead to favourable binding of EA in the α2A-AR, with respect to α2C-AR. Moreover, EA seems to better accommodate within α2A-ARs into TM5 area, closely to S200 and S204 which play a crucial role for activation of aminergic GPCRs such as the α2-AR, highlighting its promising role as a partial agonist. Consistently, EA mimics clonidine in inhibiting noradrenaline exocytosis from hippocampal nerve endings in an yohimbine-sensitive fashion that confirms the engagement of naïve α2-ARs in the EA-mediated effect.

The pressure exerted on the heart and blood vessels because of blood flow is considered as an important parameter for the cardiovascular function. It determines sufficient blood perfusion as well as transportation of nutrition, oxygen and other essential factors to every organ. Pressure in the primary arteries located near the heart and the brain, known as central blood pressure (CBP), while in peripheral arteries, known as peripheral blood pressure (PBP). Normally, CBP and PBP are correlated; however, cardiovascular disorders interfere their regulation and affect the blood flow in vital organs and accessory organs, differently. Therefore, understanding each of them in normal and disease conditions is essential for managing various cardiovascular disorders and increasing their treatment outcomes. In this review, we have described the control systems (neural, hormonal, osmotic and cellular) of the blood pressure and its regulation in hypovolemic shock using centhaquine (Lyfaquin®) as a resuscitative agent.