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Angiotensin receptor blockade has been linked to aspects of aversive learning and memory formation and to the prevention of posttraumatic stress disorder symptom development. We investigated the influence of the angiotensin receptor blocker losartan on aversive Pavlovian conditioning using a probabilistic learning paradigm. In a double-blind, randomized, placebo-controlled design, we tested 45 (18 female) healthy volunteers during a baseline session, after application of losartan or placebo (drug session), and during a follow-up session. During each session, participants engaged in a task in which they had to predict the probability of an electrical stimulation on every trial while the true shock contingencies switched repeatedly between phases of high and low shock threat. Computational reinforcement learning models were used to investigate learning dynamics. Acute administration of losartan significantly reduced participants' adjustment during both low-to-high and high-to-low threat changes. This was driven by reduced aversive learning rates in the losartan group during the drug session compared with baseline. The 50-mg drug dose did not induce reduction of blood pressure or change in reaction times, ruling out a general reduction in attention and engagement. Decreased adjustment of aversive expectations was maintained at a follow-up session 24 hours later. This study shows that losartan acutely reduces Pavlovian learning in aversive environments, thereby highlighting a potential role of the renin-angiotensin system in anxiety development. [ABSTRACT FROM AUTHOR]

Hyperthyroidism is a condition where the thyroid gland produces high levels of thyroid hormone. Heart diseases are one of the main complications of hyperthyroidism. Several studies have shown that losartan (LOS) and diminazene aceturate (DIZE) possess cardioprotection effects against cardiac hypertrophy, ischemic heart disease, and heart failure. The research aimed to investigate the cardioprotection of LOS, DIZE, and their combination in the case of levothyroxine (LT4)-induced cardiomyopathy in rats. Hyperthyroidism was induced by LT4 in drinking water (12 mg/L) for 28 days. LOS (10 mg/kg, orally) and/or DIZE (15 mg/kg, subcutaneously) were administrated in rats with hyperthyroidism for 28 days. Decreased serum creatine kinase myoglobin and lactate dehydrogenase levels and cardiac hypertrophy by DIZE and combination therapy in hyperthyroidism rats have been reported. Cardiac hemodynamic findings showed that DIZE and its combination with LOS decreased the LT4-mediated left ventricular developed pressure (LVDP), rate pressure product (RPP), and RPP recovery percentage. Elevated cardiac oxidative stress and inflammation were confirmed by decreasing cardiac superoxide dismutase (SOD) activity and increasing the total oxidative stress and tumor necrosis factor-alpha (TNF-α) levels. SOD activity and TNF-α level were reversed by LOS and DIZE administration, respectively. Generally, DIZE and combination therapy with LOS improved cardiac dysfunction caused by hyperthyroidism in rats, whereas LOS alone has not been able to effectively respond to this dysfunction. [ABSTRACT FROM AUTHOR]

β-arrestins are a family of intracellular signaling proteins that play a key role in regulating the activity of G proteincoupled receptors. The angiotensin-II type 1 receptor is an important G protein-coupled receptor involved in the regulation of cardiovascular function and has been implicated in the progression of cardiovascular diseases. In addition to canonical G protein signaling, G protein-coupled receptors including the angiotensin-II type 1 receptor can signal via β-arrestin. Dysregulation of β-arrestin signaling has been linked to several cardiovascular diseases including hypertension, atherosclerosis, and heart failure. Understanding the role of β-arrestins in these conditions is critical to provide new therapeutic targets for the treatment of cardiovascular disease. In this review, we will discuss the beneficial and maladaptive physiological outcomes of angiotensin-II type 1 receptor-dependent β-arrestin activation in different cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Obesity and adipose tissue dysfunction are important risk factors for pancreatic cancer. Pancreatic cancer is one of the most lethal cancers globally. The renin-angiotensin system (RAS) is expressed in many tissues, including adipose tissue. Dysregulation of angiotensin II and angiotensin II receptors in adipose tissue through the activation of different signaling pathways leads to adipose tissue dysfunction, including insulin resistance, adipose tissue inflammation, adipocytokines secretion, and metabolic alterations. The pathogenesis of pancreatic cancer remains uncertain. However, there is evidence that dysregulation of local angiotensin II in adipose tissue that occurs in association with obesity is, in part, responsible for the initiation and progression of pancreatic cancer. Due to the role of local angiotensin II in the dysfunction of adipose tissue, angiotensin receptor blockers may be considered a new therapeutic strategy in the amelioration of the complications related to adipose tissue dysfunction and prevention of pancreatic cancer. This review aims to consider the biological roles of local angiotensin II and angiotensin II receptors in adipose tissue dysfunction to promote pancreatic cancer progression with a focus on adipose tissue inflammation and metabolic reprogramming., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

β-arrestins are a family of intracellular signaling proteins that play a key role in regulating the activity of G protein-coupled receptors. The angiotensin-II type 1 receptor is an important G protein-coupled receptor involved in the regulation of cardiovascular function and has been implicated in the progression of cardiovascular diseases. In addition to canonical G protein signaling, G protein-coupled receptors including the angiotensin-II type 1 receptor can signal via β-arrestin. Dysregulation of β-arrestin signaling has been linked to several cardiovascular diseases including hypertension, atherosclerosis, and heart failure. Understanding the role of β-arrestins in these conditions is critical to provide new therapeutic targets for the treatment of cardiovascular disease. In this review, we will discuss the beneficial and maladaptive physiological outcomes of angiotensin-II type 1 receptor-dependent β-arrestin activation in different cardiovascular diseases., Competing Interests: Disclosures None.