Hypothalamic stimulation and electrolyte excretion: a micropuncture study

Silva-Netto, C. R.; Aires, Margarida de Mello; Malnic, Gerhard

doi:10.1152/ajprenal.1980.239.3.f206

Cited by 6 publications

(5 citation statements)

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“…In a recollection micropuncture experiment along proximal and distal renal tubules, it was found that carbachol stimulation of the lateral hypothalamic area (LHA) led to diuresis and natriuresis with only transient changes in GFR and renal plasma flow. These effects are only partially due to the release of neurohypophysial hormones, since the administration of OT and AVP promoted a further effect of LHA stimulation (479). Silva-Netto et al (478) have also shown the natriuretic effect of carbachol stimulation of the LHA in rats with intact or denervated kidneys.…”

Section: Role Of ␣-Adrenergic and Cholinergic Receptors In Controlmentioning

confidence: 98%

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Neuroendocrine Control of Body Fluid Metabolism

Antunes‐Rodrigues

Castro

Elias

et al. 2004

Physiological Reviews

397

310

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Mammals control the volume and osmolality of their body fluids from stimuli that arise from both the intracellular and extracellular fluid compartments. These stimuli are sensed by two kinds of receptors: osmoreceptor-Na+ receptors and volume or pressure receptors. This information is conveyed to specific areas of the central nervous system responsible for an integrated response, which depends on the integrity of the anteroventral region of the third ventricle, e.g., organum vasculosum of the lamina terminalis, median preoptic nucleus, and subfornical organ. The hypothalamo-neurohypophysial system plays a fundamental role in the maintenance of body fluid homeostasis by secreting vasopressin and oxytocin in response to osmotic and nonosmotic stimuli. Since the discovery of the atrial natriuretic peptide (ANP), a large number of publications have demonstrated that this peptide provides a potent defense mechanism against volume overload in mammals, including humans. ANP is mostly localized in the heart, but ANP and its receptor are also found in hypothalamic and brain stem areas involved in body fluid volume and blood pressure regulation. Blood volume expansion acts not only directly on the heart, by stretch of atrial myocytes to increase the release of ANP, but also on the brain ANPergic neurons through afferent inputs from baroreceptors. Angiotensin II also plays an important role in the regulation of body fluids, being a potent inducer of thirst and, in general, antagonizes the actions of ANP. This review emphasizes the role played by brain ANP and its interaction with neurohypophysial hormones in the control of body fluid homeostasis.

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Section: Role Of ␣-Adrenergic and Cholinergic Receptors In Controlmentioning

confidence: 98%

“…Several other laboratories have also made important contributions to understanding of the role played by the CNS in the control of body fluid homeostasis (for review, see Refs. 9, 65, 121, 135,153,170,172,255,257,478,479).…”

Section: A Control Of Hydromineral Balance By a Brain Neural Circuitmentioning

confidence: 99%

Neuroendocrine Control of Body Fluid Metabolism

Antunes‐Rodrigues

Castro

Elias

et al. 2004

Physiological Reviews

397

310

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“…Central administration of carbachol induces diuretic, natriuretic, and kaliuretic responses in adults (43)(44)(45). An increase of blood pressure may affect renal excretion (5).…”

Section: Discussionmentioning

confidence: 99%

Central cholinergic mechanisms mediate swallowing, renal excretion, and c-fos expression in the ovine fetus near term

Shi

Mao²,

Zeng³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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mechanisms mediate swallowing, renal excretion, and c-fos expression in the ovine fetus near term. Am J Physiol Regul Integr Comp Physiol 296: R318 -R325, 2009. First published September 10, 2008 doi:10.1152/ajpregu.90632.2008.-Fetal swallowing and renal metabolism contribute importantly to amniotic and body fluid homeostasis. To determine central cholinergic modulation of swallowing activity and renal excretion associated with neural activity, we examined the effects of intracerebroventricular injection of carbachol, a cholinergic agonist, in ovine fetuses at 0.9 gestation. Fetuses were chronically prepared with thyrohyoid, nuchal and thoracic esophagus, and diaphragm electromyogram electrodes, as well as lateral ventricle and vascular catheters. Electrodes were also implanted on the parietal dura for determination of fetal electrocorticogram (ECoG). After 5 days of recovery, fetal swallowing, ECoG, and urine output were monitored during basal period and the experimental period following intracerebroventricular injection of 0.9% NaCl as the control (n ϭ 5) or carbachol (3 g/kg, n ϭ 5). Central carbachol did not significantly change fetal low voltage (LV) and high voltage (HV) ECoG temporal distributions. However, swallowing activity during LV ECoG was elevated significantly after intracerebroventricular carbachol. Associated with the swallowing activation, c-fos immunoreactivity in the putative dipsogenic center, subfornical organ, was enhanced significantly. The fetal urine flow rate and renal Na ϩ , K ϩ , and Cl Ϫ excretion were markedly increased following intracerebroventricular carbachol and sustained at the high level for at least 2 h. The results indicate that the central cholinergic mechanism is established and functional in regulation of fetal behavior and renal excretion at least at 0.9 gestation, which plays an important role in maintenance of fetal body fluid homeostasis.fetus; carbachol; thirst STIMULATED WATER INTAKE, IN concert with renal water and electrolyte excretion, is the fundamental physiological mechanism that maintains body fluid homeostasis. It is well established that in adult animals, central cholinergic mechanisms play an important role in the control of cardiovascular and body fluid homeostasis (12,15). Central application of cholinergic agonist, carbachol, elicits a variety of physiological responses, including natriuetic, dipsogenic, and pressor responses, as well as vasopressin secretion (2,23,44). Our recent studies demonstrated that intracerebroventricular injection of carbachol also produced pressor responses (42) in the ovine fetus near term, indicating that the central cholinergic mechanism-mediated cardiovascular regulation is functional before birth. However, the role of central cholinergic mechanisms in fetal fluid balance and renal excretion is largely unknown.Progress has been made in demonstrating that swallowing activity can be regulated by hyperosmotic, hypovolemic, and other stimuli such as ANG II and neuropeptide Y in late gestation (31,33,48,49). Fetal renal flu...

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“…Conversely, studies have shown that electrolytic lesion of the hypothalamic regions in conscious rats reduces salt intake and the pressor response to cholinergic and noradrenergic microinjection into the median preoptic nucleus (Covian et al, 1975). Prior findings have also revealed that central α- and β-adrenergic receptors response are involved in CNS hydrosaline homeostasis (Gontijo and Kopp, 1994; Covian et al, 1975; Silva-Netto et al, 1983, 1980; Franci et al, 1980; Gontijo et al, 1991; Gontijo et al, 1990).…”

Section: Introductionmentioning

confidence: 98%

Effect of intracerebroventricular epinephrine microinjection on blood pressure and urinary sodium handling in gestational protein-restricted male adult rat offspring

et al. 2019

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In this study, we hypothesized that blunting of the natriuresis response to intracerebroventricularly (ICV) microinjected adrenergic agonists is involved in the development of hypertension in maternal low-protein intake (LP) offspring. A stainless steel cannula was stereotaxically implanted into the right lateral ventricle (LV), then we evaluated the ICV administration of adrenergic agonists at increasing concentrations, and of α1 and α2-adrenoceptor antagonists on blood pressure and urinary sodium handling in LP offspring relative to an age-matched normal-protein intake (NP) group. We confirmed that epinephrine (Epi) microinjected into the LV of conscious NP rats leads to enhanced natriuresis followed by a reduction in arterial pressure. This response is associated with increased proximal and post-proximal sodium excretion accompanied by an unchanged glomerular filtration rate. The current study showed, in both NP and LP offspring, that the natriuretic effect of Epi injection into the LV was abolished by prior local microinjection of an α1-adrenoceptor antagonist (prazosin). Conversely, LV α2-adrenoceptor antagonist (yohimbine) administration potentiated the action of Epi. The LV yohimbine pretreatment normalized urinary sodium excretion and reduced the blood pressure in LP compared with age-matched NP offspring. These are, as far as we are aware, the first results showing the role of central adrenergic receptors’ interaction on hypertension pathogenesis in maternal LP fetal-programming offspring. This study also provides good evidence for the existence of central nervous system adrenergic mechanisms consisting of α1 and α2-adrenoceptors, which work reciprocally on the control of renal sodium excretion and blood pressure. Although the precise mechanism of the different natriuretic response of NP and LP rats is still uncertain, these results lead us to speculate that inappropriate neural adrenergic pathways might have significant effects on tubule sodium transport, resulting in the inability of the kidneys to control hydrosaline balance and, consequently, an increase in blood pressure.

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Hypothalamic stimulation and electrolyte excretion: a micropuncture study

Cited by 6 publications

References 0 publications

Neuroendocrine Control of Body Fluid Metabolism

Neuroendocrine Control of Body Fluid Metabolism

Central cholinergic mechanisms mediate swallowing, renal excretion, and c-fos expression in the ovine fetus near term

Effect of intracerebroventricular epinephrine microinjection on blood pressure and urinary sodium handling in gestational protein-restricted male adult rat offspring

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