Influence of up-regulated renin—angiotensin system on the exploration, anxiety-related behavior and object recognition

Abstract

The renin-angiotensin system (RAS) plays an important role in the development of hypertension and has serious consequences on behaviour. The aim of our study was to investigate the effect of hypertension, induced by up-regulated RAS, on the exploration, anxiety-related behaviour and object recognition in laboratory rats. In the experiment, 12 weeks old normotensive Sprague-Dawley (SD) and hypertensive TGR(mREN2)27 (TGR) male rats with up-regulated RAS were used. In the open-field test, the TGR rats were less active in ambulating, rearing and sniffing and more active in self-grooming and urinating than SD ones. In the elevated plus-maze test, the TGR rats showed lower frequency of total arm entries, closed arm entries and higher frequency of defecation than in controls. In the emergence test, TGR rats did not show significant differences. In the novel object recognition task, the TGR rats spent less time with exploration of both familiar and unfamiliar objects but preferred the novel object over the familiar one and exhibited higher percentage of the total exploring time spent with novel object exploration than SD rats. Our results indicate that the TGR rats are less actively exploring, show some modifications of emotional/anxiety-related behavior and exhibited better recognition abilities.

Validation of Brain Angiotensin System Blockade as a Novel Drug Target in Pharmacological Treatment of Neuropsychiatric Disorders

“…While both beta-blockers and tranquillizers failed in providing long-term benefits in reduction of stress-related anxiety, AT 1 R have recently received greater attention, and scientists have employed the selective AT 1 R antagonists to demonstrate their anxiolytic potential [137]. The phenomenon of elevated Ang II levels causing anxiety has been widely supported by studies showing the development of an anxiety-like behavior following Ang II administration and in transgenic rats with the up-regulated RAS system [138]. The literature constantly reports the critical role of AT 1 R in modulating stress-associated anxiety [139].…”

Sex differences in social stress-induced pressor and behavioral responses in normotensive and hypertensive rats

“…Behavioral changes are usually observed immediately after stress, but in many cases they persist after discontinuation of the stressful stimuli (Hashiguchi et al 1997). Behavioral alterations can be manifested in activity level, emotionality and anxiety, as well as in learning and memory processes (Ramos and Mormede 1998;Hata et al 2001;Keeney et al 2001;Krskova et al 2009). In addition to discrepancies mentioned above, sex and family history of hypertension represent other important issues that may interact with environmental factors and participate in development of cardiovascular disorders.…”