G A Head

..Furthermore, the noradrenergic innervation may be associated with a 42 kDa imidazoline receptor protein...

..The elevation of blood pressure and RSNA induced by a HFD is predominantly mediated by central actions of leptin. Central actions of insulin contribute a smaller proportion of the hypertension but independently of RSNA...

..We conclude that while HR is generally lower in the laboratory, a valid representation of MAP and RSNA can be given by laboratory measurements...

..Increased plasma leptin and insulin may contribute to the initiation of hypertension but are not required for maintenance of mean arterial pressure, which likely lies in alterations in the response of neurons in the hypothalamus...

..The objective of this initiative is to provide ABP equivalents for BP cut-points for treatment initiation and targets to be included into guidelines...

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..We applied this method to determine whether morning BP(Power) is different in hypertensives compared to normotensives, males compared to females or altered by antihypertensive treatment...

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..We aimed to derive age and sex related ambulatory blood pressure equivalents to clinic blood pressure thresholds for diagnosis and treatment of hypertension...

..7. Antihypertensive drugs and dosing regimes are being developed which may be useful adjuncts to standard therapy for preventing morning hypertension and hopefully also reducing cardiovascular damage or events...

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..We are therefore only at the threshold of an exciting new era as we begin to understand the diverse and complex nature of their function...

..As such, sympathoinhibitory agents such as rilmenidine are very suitable and very effective agents for the treatment of renovascular hypertension...

..These studies suggest that the contribution of the sympathetic nervous system is greater in 2K1C hypertension and that imidazoline agents may be beneficial in treating renovascular hypertension...

..The ability of the double logistic method to determine the diurnal blood pressure rates of change independently is key to determining new markers for cardiovascular risk...

..Thus, aromatase activity is critical for normal autonomic control of the heart and, hence, for reducing the deleterious effects of high BP variability...

..To determine the suitability of a new logistic curve fitting procedure to measure the diurnal rates of transition from the active to the asleep periods separately...

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..These studies suggest that the major medullary pressor site of action of Ang II when injected into the hindbrain cerebro-spinal fluid of anaesthetized rabbits is the RVLM where it facilitates baroreflex control of RSNA...

..The central receptor involved, be it a central imidazoline receptor or an alpha2-adrenoceptor and its location, is less certain...

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..Our hypothesis brings together opposing points of view that the mechanism for hypotension must involve either the imidazoline receptor or the alpha2-adrenoceptor. Clearly both are important...

..In conclusion, our studies suggest that imidazoline receptors and alpha 2-adrenoceptors within the RVLM are important for the antihypertensive actions of clonidine-like drugs...

..To determine the influence of imidazoline receptors and alpha2-adrenoceptors in the rostral ventrolateral medulla (RVLM) on the renal sympathetic baroreflex...

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..This provides one model of the mechanisms by which central peptide transmitters may alter the action of other transmitters...

..This provides a number of targets for future development of useful pharmacological agents...

..We conclude that the various components of the MAP and HR responses are mediated through distinctive NA pathways; the deficits of a given lesion could be due to either to loss of NA cell bodies or of NA fibers of passage...

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..We conclude that the RVLM plays a key role in circulatory control in conscious rabbits. However, we find no evidence for the role of ANG II receptors in the RVLM in the moment-to-moment regulation of AP and RSNA...

..However, the previously described apparent desensitisation to the antihypertensive effect of rilmenidine could not be observed in rabbits, suggesting marked species differences in the mechanism and site of action of rilmenidine...

..A relatively moderate effect of rilmenidine on arterial pressure in conscious, chronically instrumented rabbits may relate to a lower level of sympathetic drive compared with anesthetized animals...

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..These data demonstrate a novel long-term modulation of cardiac baroreflexes by endogenous ANG II that is independent of blood pressure level...

..The sympathoexcitatory AT1 receptors appear to be activated during stress, surgery and anesthesia...

..Under normal baroreceptor input the former pressor pathway is completely inhibited. Thus the role of the central renin-angiotensin system may be of greater physiological importance in conditions where the baroreflex is suppressed...

..In SAD rabbits, almost all the changes to HR are mediated through the cardiac sympathetic and the lesions have little effect on HR...

..CONCLUSIONS: This study provides first published evidence that superoxide in the DMH is important in the regulation of acute hypertensive and tachycardic responses to mental stress...

..This effect appears to be mediated postjunctionally, not through enhanced neural norepinephrine release, and may contribute to the development and/or maintenance of hypertension in these models...

..Furthermore, the enhanced vagal bradycardia observed in very young SHR which was due primarily to the earlier establishment of the adult vagal response pattern may indicate accelerated vagal development in this strain compared to WKY...

..In this study, we examined whether the renin enhancer deficit alters the acute pressor response to emotional stress in mice...

..To determine whether the hypotensive and sympathetic baroreflex inhibition by rilmenidine administered systemically are mediated via imidazoline receptors in the rostral ventrolateral medulla (RVLM)...

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..Furthermore, all agents showed a propensity to produce rebound hypertension with imidazoline receptor blockade. However, only clonidine showed a rebound phenomenon when challenged by acute central alpha(2)-adrenoceptor blockade..

..98). These findings indicate that the hypertension is largely attributable to sympathetic nervous system activity, possibly generated through greater levels of arousal regulated by neurons located in the medial amygdala...

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..Furthermore, although cardiac hypertrophy developed, its presence did not appear to be sufficient to produce a decrease in barosensitivity independent of raised arterial pressure...

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..The paradoxical reduction in hypothalamic neuronal activation by leptin suggests a marked "selective leptin resistance" in these animals...

..Thus, sodium retention in obesity might be driven not only by increased RSNA, but also by increased responsiveness of the kidney to RSNA...

..The greater depressor effect of acute ganglion blockade in hypertensive rabbits suggests that the sympathetic nervous system exerts increased vasoconstriction in the peripheral vasculature in Ang II-induced hypertension...

..These findings do not support the hypothesis that enhanced neural control of renal function contributes to maintenance of hypertension associated with activation of the renin-angiotensin system...

..Conversely, angiotensin II, acting via AT1 receptors, may selectively modulate, in the DMH, cardiovascular response to stress, but not feeding...

..7-fold). These results show that administration of the dopamine D(2)/D(3) receptor agonist quinpirole causes profound and long-lasting changes in the central integration of the sympathetic baroreceptor-vasomotor reflex...

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..In conclusion, our data suggest that global loss of arginase II activity results in hypertension. We suggest that this strain of mouse warrants further investigation as a potentially novel model of hypertension...

..We have shown that heart failure causes an impairment of the central noradrenergic system's response to acute sympatho-excitation but does not affect the hypothalamo-pituitary-adrenocortical response...

..These have led to a better understanding of sympathoactivation in hypertension and its underlying mechanisms...

..Therefore, in the present study, we hypothesize that an increased contribution of the SNS in BPH/2J mice may culminate in a greater pressor response to stressful stimuli in these hypertensive mice than normotensive (BPN/3J) mice...

..Thus, prior inhibition of NOS results in endothelial dysfunction in early diabetes, since the diabetes-induced reduction in EDHF function cannot be compensated by increases in NO production...

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..These results suggest that AT1 receptors in the RVLM are important in mediating the pressor effects of emotional stress in conscious rabbits...

..Together with our previous studies, these results also indicate that superoxide is a key mediator of excitatory actions of angiotensin II in RVLM during acute stress...

..These findings suggest that there is desensitization of circumventricular organs but sensitization of neurons in hypothalamic regions to long-term angiotensin II infusion...

..HSD can selectively reinforce the cardiovascular response to negative stress in AT(1A)(-/-) mice. However, there is little interaction between AT(1A) receptors, excess dietary sodium and feeding-induced cardiovascular arousal...

..The EAA receptors are critically important in initiating the pressor and sympathoexcitatory responses to acute emotional stress, but play relatively little role in the maintenance of these responses...

..By activating this forebrain pathway methyldopa minimises the baroreflex compensation that might normally be expected following a reduction in blood pressure...

..Renal insufficiency is associated with the development of cardiovascular disease...

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..In this study, we examined the influence of angiotensin AT(1A) receptors on circadian BP variation, and specifically on its behavioral activity-related and -unrelated components...

..Angiotensin-converting enzyme (ACE)2 opposes the actions of angiotensin (Ang) II by degrading it to Ang 1-7...

..Finally, in atrial appendages from patients with AF, PI3K activation was lower compared with tissue from patients in sinus rhythm. These results suggest a link between PI3K(p110alpha) and AF...

..In contrast, the renal vasodilator effect of captopril is not modulated by ongoing RSNA and is associated with impairment of autoregulation of RBF...

..In conclusion, the renin enhancer is critical for renin gene expression and physiological sequelae, including response to alteration in salt intake. The REKO mouse may be useful as a low renin expression model...

..The algorithm proved to be superior against three commercially available heartbeat detectors yielding an error rate of 0.09%...