MAP (24 hour typical) in MS (100.93.0 mmHg) and C rats (104.93.2 mmHg) was equivalent ahead of infusion of ang II (desk 1;body 2A). ang II had not been different in anesthetized control and MS rats. Nevertheless, the chronic infusion of ang II (65 ng/time, s.c.) elicited an exaggerated hypertensive response in MS in comparison to control rats (p<0.05). Amazingly, HR was significantly increased during the second week of ang II infusion in MS compared with control rats (p<0.05). This Isomangiferin enhanced ang II sensitivity was accompanied by a greater vascular inflammatory response in MS vs. control rats. Chronic ang II-infusion increased vascular wall structure in both groups similarly. These data indicate that early life stress sensitizes rats to an increased hemodynamic and inflammatory response during ang II-induced hypertension. Keywords:maternal separation, ang II-induced hypertension, vascular inflammation == Introduction == Traditionally, cardiovascular and metabolic disorders are thought to result from lifestyle risk factors acting upon a certain genetic background. More recently, investigators have described a phenomenon whereby adverse stimuli affect the fetal environment altering the development of organs or Isomangiferin tissues increasing the susceptibility to disease later in life, known as early or fetal origins of adult disease (13). In humans, adverse experiences in early childhood create and/or interact with genetic-based vulnerabilities which are correlated with a greater incidence of endocrine, cardiovascular and metabolic disease in adulthood (46). In animal models, it is well accepted that environmental factors during development influence the risk for multiple forms of chronic adult diseases such as depression, diabetes, and heart disease (79). The renin-angiotensin system (RAS) is an important regulator of arterial pressure and body fluid balance through both the systemic and the intra-renal actions of angiotensin II (ang II) (10). Excessive activation of the RAS also stimulates the sympathetic nervous system as well as mediating vascular hypertrophy and pro-inflammatory pathways. These ang II-dependent mechanistic pathways are known to contribute towards cardiovascular dysfunction, especially Isomangiferin hypertension, in adults. Animal models of fetal programming, such as maternal low protein diet or early gestational exposure to glucocorticoid, lead to alterations in RAS activity and adult onset of hypertension and renal dysfunction (11,12). Maternal separation is a widely used animal model of chronic behavioral stress during early life (13,14). Variations in maternal care during early life are considered a stressful experience associated with alterations in Isomangiferin the endocrine response (15,16). Male rat pups separated from their mothers daily for a prolonged period (180 min) show, as adults, abnormal anxiety-related behavior and exaggerated endocrine responses to an acute stress; whereas females display normal or minimally-exaggerated responses (14,17,18). In a study of over 17,000 adults, early life stress or adverse childhood events is reported to be highly correlative with ischemic heart disease in adulthood more so than the traditional risk factors of smoking, obesity, and hypertension (4). Despite these dramatic observations, very little research has been conducted to determine whether early life behavioral stress leads to cardiovascular dysfunction and/or activation of the RAS system. We hypothesized that early life stress may activate the RAS signaling pathway leading to cardiovascular dysfunction in adults. This study was designed to 1) investigate whether the rat model of early life stress, maternal separation, influences basal parameters of cardiovascular function such as blood pressure, heart rate, vascular OBSCN morphology and vascular inflammation in male rats; and, 2) elucidate whether maternal separation sensitizes male rats to ang II-induced cardiovascular dysfunction by monitoring the same parameters. == Methods == == Early life stress: maternal separation protocol == Close to delivery, pregnant Wistar Kyoto rats (WKY) were carefully observed to determine the exact day of birth (postnatal day 0). Approximately half of the male pups from each litter were removed from the mothers cage and their tails were snipped and cauterized with silver nitrate for identification as maternally separated (MS). From postnatal days 2 to 14 of life, MS pups were separated from their mothers and littermates, at the same time of day by transferring the pups to a clean cage in an incubator (301 C) for 3 hours. The control group (C) consisted of counterparts that remained with their mother and were non-handled. Routinely, each breeding cycle includes 5 breeding pairs at one time. When the 5 female rats deliver their pups, it generated a total number of 1824 male.
