The Hypothalamus and Cardiovascular Regulation

Coote, John H.

doi:10.1007/978-1-4419-9054-9_6

Cited by 16 publications

(44 citation statements)

References 172 publications

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“…THE HYPOTHALAMIC ARCUATE NUCLEUS (ARCN) may play a significant role in cardiovascular regulation (10,38). Consistent with this notion, we (31) have recently reported that chemical stimulation of the ARCN elicited increases in mean arterial pressure (MAP), heart rate (HR), and sympathetic nerve activity (SNA).…”

mentioning

confidence: 70%

“…Microinjections of ANG-(1-12) (1 mM) at different rostrocaudal levels of the ARCN elicited similar cardiovascular responses ( Table 2). Microinjections of ANG II (1 mM) into the ARCN elicited greater cardiovascular responses compared with the same concentration of ANG- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) at the same levels ( Table 2). The onset of cardiovascular responses to microinjections of ANG-(1-12) (1 mM) into the ARCN (11.2 Ϯ 1.2 s) was significantly (P Ͻ 0.05) longer than the onset of action (8.3 Ϯ 0.6 s) of microinjection of ANG II (1 mM) at the same site.…”

Section: Resultsmentioning

confidence: 97%

“…Cardiovascular responses to microinjections of ANG- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) into the ARCN. The ARCN (ϳ2 mm long in the rostrocaudal direction) was arbitrarily divided into the following three equal segments (the coordinates mentioned for each segment indicate the level caudal to the bregma): the rostral segment (2.1-2.9 mm), middle segment (2.9 -3.7 mm), and caudal segment (3.7-4.5 mm).…”

Section: Resultsmentioning

confidence: 99%

“…Site specificity of ANG- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)-induced responses in the ARCN. We (31) have previously reported that microinjections of NMDA (10 mM) into the ARCN at different rostrocaudal levels (2.3-4.16 mm caudal to the bregma) and the dorsomedial hypothalamic nucleus (DMN; 3.6 caudal to bregma, 0.2 lateral to the midline, and 9.0 deep from the dura) elicited pressor and tachycardic responses.…”

Section: Resultsmentioning

confidence: 99%

“…Bilateral microinjections of ANG- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) into the NTS have been reported to elicit transient depressor responses and an attenuation of baroreflex sensitivity (1). Chronic immunoneutralization of endogenous brain ANG- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) by intracerebroventricular injections of anti-ANG-(1-12) IgG in hypertensive rats have been reported to elicit antihypertensive effects (21). Several components of the renin-ANG system (RAS) have been identified in the ARCN.…”

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confidence: 99%

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The hypothalamic arcuate nucleus: a new site of cardiovascular action of angiotensin-(1–12) and angiotensin II

Arakawa

Chitravanshi

Sapru

2011

American Journal of Physiology-Heart and Circulatory Physiology

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Arakawa H, Chitravanshi VC, Sapru HN. The hypothalamic arcuate nucleus: a new site of cardiovascular action of angiotensin-(1-12) and angiotensin II. Am J Physiol Heart Circ Physiol 300: H951-H960, 2011. First published December 24, 2010 doi:10.1152/ajpheart.01144.2010.-The hypothalamic arcuate nucleus (ARCN) has been reported to play a significant role in cardiovascular regulation. It has been hypothesized that the ARCN may be one of the sites of cardiovascular actions of angiotensins (ANGs). Experiments were carried out in urethaneanesthetized, artificially ventilated, adult male Wistar rats. The ARCN was identified by microinjections of N-methyl-D-aspartic acid (NMDA; 10 mM). Microinjections (50 nl) of ANG-(1-12) (1 mM) into the ARCN elicited increases in mean arterial pressure (MAP), heart rate (HR), and greater splanchnic nerve activity (GSNA). The tachycardic responses to ANG-(1-12) were attenuated by bilateral vagotomy. The cardiovascular responses elicited by ANG-(1-12) were attenuated by microinjections of ANG II type 1 receptor (AT1R) antagonists but not ANG type 2 receptor (AT2R) antagonist. Combined inhibition of ANG-converting enzyme (ACE) and chymase in the ARCN abolished ANG-(1-12)-induced responses. Microinjections of ANG II (1 mM) into the ARCN also increased MAP and HR. Inhibition of ARCN by microinjections of muscimol (1 mM) attenuated the pressor and tachycardic responses to intravenously administered ANG-(1-12) and ANG II (300 pmol/kg each). These results indicated that 1) microinjections of ANG-(1-12) into the ARCN elicited increases in MAP, HR, and GSNA; 2) HR responses were mediated via both sympathetic and vagus nerves; 3) AT1Rs, but not AT2Rs, in the ARCN mediated ANG-(1-12)-induced responses; 4) both ACE and chymase were needed to convert ANG-(1-12) to ANG II in the ARCN; and 5) ARCN plays a role in mediating the cardiovascular responses to circulating ANGs. blood pressure; heart rate; microinjection; N-methyl-D-aspartic acid; sympathetic nerve activity THE HYPOTHALAMIC ARCUATE NUCLEUS (ARCN) may play a significant role in cardiovascular regulation (10, 38). Consistent with this notion, we (31) have recently reported that chemical stimulation of the ARCN elicited increases in mean arterial pressure (MAP), heart rate (HR), and sympathetic nerve activity (SNA). These reports have provided a basis for investigations on different neurotransmitters and neuromodulators in the ARCN that may play a role in the regulation of cardiovascular function in normal and pathological states.A new endogenous angiotensin (ANG), ANG-(1-12), has recently been identified (30,44). Intravenous administration of this peptide has been reported to elicit an immediate pressor response in the rat, and this effect was blocked by prior administration of an ANG-converting enzyme (ACE) inhibitor or an ANG II type 1 receptor (AT 1 R) antagonist (30). These data indicated that in the periphery, ANG-(1-12) exerts its actions via a rapid conversion to ANG II (30). High concentrations of ANG-(1-12) have been reported in th...

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mentioning

confidence: 70%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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The hypothalamic arcuate nucleus: a new site of cardiovascular action of angiotensin-(1–12) and angiotensin II

Arakawa

Chitravanshi

Sapru

2011

American Journal of Physiology-Heart and Circulatory Physiology

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Homeostasis and stress

Coote

2005

Clin Auton Res

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Key components of normal body function rely on an efficient cardiovascular system to provide the fuel to meet changing energy demands. This requires mechanisms that enable blood flow to various organs to be selectively increased or decreased. This is provided by control of cardiovascular tone, which has been traditionally considered the province of a group of neurones in the medulla oblongata. As a consequence for many years attention was focussed on these neurones as a source of increased sympathetic activity associated with cardiovascular disease. The review by Benarroch in this volume shows how this view is changing.Attention has now shifted to the forebrain for which there is convincing evidence implicating nuclei of the Hypothalamus as major contributors to sympathetic activity. It has often been stated that the Hypothalamus is responsible for complex overt behaviour patterns with somatic, endocrine and autonomic components and as such it only participates in cardiovascular regulation in so far as this is an integral part of the behaviour. However it is also clear that cardiovascular adjustments are essential for maintaining the constancy of the internal environment. In this homeostatic role the Hypothalamus is critically concerned with fluid balance, energy balance and core temperature regulation. In these responses there is a differential distribution of cardiac output to specific vascular beds. Such differential patterns of activation/inhibition of sympathetic nerves supplying different cardiovascular targets occur in response to a host of stimuli from both external and internal environments. These patterns have a unique signature related to the site and sensitivity of the afferent nerve receptors. The integration of the signals from these receptors and the initiation of circulatory responses which cater for specific needs is not processed directly by the medulla oblongata but is largely the role of the Hypothalamus.Structurally the Hypothalamus represents only a trifling portion of the brain yet it is anatomically and neurochemically complex. It is made up of several distinct groups of neurones differing in morphology and neurochemistry which modern neuroanatomical, physiological and gene based approaches reveal, project to groups of autonomic neurones in the brainstem and spinal cord. One of these Hypothalamic groups is the Paraventricular Nucleus (PVN). The review by Benarroch in this issue draws attention to the neurochemical heterogeneity and the many connections the PVN has with neurones involved in endocrine and autonomic function. However most importantly the review focuses on recent studies concerning its role when homeostatic control goes awry as in stress and cardiovascular disease. The review shows that the PVN is a target for afferent signals from numerous sources and also that PVN neurones project via many routes to modify sympathetic activity. Perhaps less well emphasised are the studies showing that PVN axons as well as targeting regions of the medulla oblongata also project directly to in...

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Role of the hypothalamic arcuate nucleus in cardiovascular regulation

Sapru

2013

Autonomic Neuroscience

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Recently the hypothalamic arcuate nucleus (Arc) has been implicated in cardiovascular regulation. Both pressor and depressor responses can be elicited by the chemical stimulation of the Arc. The direction of cardiovascular responses (increase or decrease) elicited from the Arc depends on the baseline blood pressure. The pressor responses are mediated via increase in sympathetic nerve activity and involve activation of the spinal ionotropic glutamate receptors. Arc-stimulation elicits tachycardic responses which are mediated via inhibition of vagal input and excitation of sympathetic input to the heart. The pathways within the brain mediating the pressor and tachycardic responses elicited from the Arc have not been delineated. The depressor responses to the Arc-stimulation are mediated via the hypothalamic paraventricular nucleus (PVN). Gamma aminobutyric acid type A receptors, neuropeptide Y1 receptors, and opiate receptors in the PVN mediate the depressor responses elicited from the Arc. Some circulating hormones (e.g., leptin and insulin) may reach the Arc via the leaky blood-brain barrier and elicit their cardiovascular effects. Although the Arc is involved in mediating the cardiovascular responses to intravenously injected angiotensin II and angiotensin-(1-12), these effects may not be due to leakage of these peptides across the blood-brain barrier in the Arc; instead, circulating angiotensins may act on neurons in the SFO and mediate cardiovascular actions via the projections of SFO neurons to the Arc. Cardiovascular responses elicited by acupuncture have been reported to be mediated by direct and indirect projections of the Arc to the RVLM.

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The Hypothalamus and Cardiovascular Regulation

Cited by 16 publications

References 172 publications

The hypothalamic arcuate nucleus: a new site of cardiovascular action of angiotensin-(1–12) and angiotensin II

The hypothalamic arcuate nucleus: a new site of cardiovascular action of angiotensin-(1–12) and angiotensin II

Homeostasis and stress

Role of the hypothalamic arcuate nucleus in cardiovascular regulation

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