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Brain Renin (brain + renin)
Selected AbstractsINHIBITION OF BRAIN RENIN,ANGIOTENSIN SYSTEM IMPROVES DIASTOLIC CARDIAC FUNCTION FOLLOWING MYOCARDIAL INFARCTION IN RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2009IG Araujo SUMMARY 1Recently, we demonstrated that oral captopril treatment improved diastolic function and attenuated cardiac remodelling after myocardial infarction (MI) in rats. Considering the feasible role of the brain renin,angiotensin system (RAS) in heart failure, in the present study we investigated the role of the captopril injected intracerebroventricularly (i.c.v.) on the progression of cardiac dysfunction. 2Male Wistar rats underwent experimental MI or sham operation. Infarcted animals received daily i.c.v. injections of captopril (approximately 200 mg/kg; MI + Cap) or saline (MI) from 11 to 18 days after infarction. Electro- and echocardiogram assessments were performed before and after i.c.v. treatment (10 and 18 days after MI, respectively). Water and hypertonic saline ingestion were determined daily between 12 and 16 days after MI. 3Electrocardiograms from the MI and MI + Cap groups showed signs that resembled large MI before and after i.c.v. treatment. However, despite similar systolic dysfunction observed in both groups, only captopril-treated rats exhibited reduced left ventricular (LV) dilatation and improved LV filling, as assessed by echocardiograms, and low levels of water ingestion compared with the saline-treated control group. 4The results of the present study suggest that the brain RAS may participate in the development of cardiac dysfunction induced by ischaemia and that inhibition of the brain RAS may provide a new strategy for the prevention of diastolic dysfunction. [source] Candesartan pretreatment is cerebroprotective in a rat model of endothelin-1-induced middle cerebral artery occlusionEXPERIMENTAL PHYSIOLOGY, Issue 8 2009Adam P. Mecca Endogenous levels of angiotensin II (Ang II) are increased in the cortex and hypothalamus following stroke, and Ang II type 1 receptor blockers (ARBs) have been shown to attenuate the deleterious effects in animal stroke models using middle cerebral artery (MCA) intraluminal occlusion procedures. However, the endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO) model of cerebral ischaemia is thought to more closely mimic the temporal events of an embolic stroke. This method provides rapid occlusion of the MCA and a gradual reperfusion that lasts for 16,22 h. The aim of the present study was to evaluate whether systemic administration of an ARB prior to ET-1-induced MCAO would provide cerebroprotection during this model of ischaemic stroke. Injection of 3 ,l of 80 ,m ET-1 adjacent to the MCA resulted in complete occlusion of the vessel that resolved over a period of 30,40 min. Following ET-1-induced MCAO, rats had significant neurological impairment, as well as an infarct that consisted of 30% of the ipsilateral grey matter. Systemic pretreatment with 0.2 mg kg,1 day,1 candesartan for 7 days attenuated both the infarct size and the neurological deficits caused by ET-1-induced MCAO without altering blood pressure. This study confirms the cerebroprotective properties of ARBs during ischaemic stroke and validates the ET-1-induced MCAO model for examination of the role of the brain renin,angiotensin system in ischaemic stroke. [source] Oestrogenic Regulation Of Brain AngiotensinogenJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2004K. J. Greenland Abstract Oestrogens are now recognized as playing a regulatory role on components of the systemic renin,angiotensin system, such as its precursor, angiotensinogen (AGT). In the brain, this role is poorly understood. The aim of this study was to investigate the influence of oestrogens on brain AGT of female rats at different stages of the oestrous cycle, in pregnancy and following ovariectomy with and without hormone replacement. AGT content of different brain regions was also studied in male rats treated with oestrogens. The brain was divided into five regions: cortex, cerebellum, brainstem, midbrain and thalamus/hypothalamus, and AGT was measured by direct radioimmunoassay using a highly specific AGT antibody. Cyclical fluctuations in AGT content were observed in all regions except the cerebellum over the course of the 4-day oestrous cycle, with peak concentrations at estrus and lowest concentrations at metestrus. Following ovariectomy, brain AGT was significantly decreased in the thalamic/hypothalamic region, an effect that was reversed by oestrogen-replacement. In pregnant rats, AGT contents were elevated in the brainstem region. Oestrogen treatment of male rats induced significant increases in AGT concentrations in all areas except the cortex. In summary, these results show that oestradiol has actions on brain AGT that are region-specific and dependent on the particular physiological and reproductive context. Moreover, the changes in AGT concentrations in the oestrous cycle suggest the involvement of other factors besides oestrogen. Finally, this study supports the view that the brain renin,angiotensin system has a broad role in oestrogen-modulated brain functions beyond those specific to the hypothalamic,pituitary,ovarian axis. [source] INHIBITION OF BRAIN RENIN,ANGIOTENSIN SYSTEM IMPROVES DIASTOLIC CARDIAC FUNCTION FOLLOWING MYOCARDIAL INFARCTION IN RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2009IG Araujo SUMMARY 1Recently, we demonstrated that oral captopril treatment improved diastolic function and attenuated cardiac remodelling after myocardial infarction (MI) in rats. Considering the feasible role of the brain renin,angiotensin system (RAS) in heart failure, in the present study we investigated the role of the captopril injected intracerebroventricularly (i.c.v.) on the progression of cardiac dysfunction. 2Male Wistar rats underwent experimental MI or sham operation. Infarcted animals received daily i.c.v. injections of captopril (approximately 200 mg/kg; MI + Cap) or saline (MI) from 11 to 18 days after infarction. Electro- and echocardiogram assessments were performed before and after i.c.v. treatment (10 and 18 days after MI, respectively). Water and hypertonic saline ingestion were determined daily between 12 and 16 days after MI. 3Electrocardiograms from the MI and MI + Cap groups showed signs that resembled large MI before and after i.c.v. treatment. However, despite similar systolic dysfunction observed in both groups, only captopril-treated rats exhibited reduced left ventricular (LV) dilatation and improved LV filling, as assessed by echocardiograms, and low levels of water ingestion compared with the saline-treated control group. 4The results of the present study suggest that the brain RAS may participate in the development of cardiac dysfunction induced by ischaemia and that inhibition of the brain RAS may provide a new strategy for the prevention of diastolic dysfunction. [source] | ||||||||||