Several findings suggest that A1 noradrenergic neurons in the caudal ventrolateral medulla (CVLM) contribute to body fluid homeostasis and cardiovascular regulation. Recently we demonstrated that the renal vasodilation induced by infusion of hypertonic saline (HS) depends on the integrity of the A1 neurons. Here we determined the effect of lesions of these neurons on the inhibition of the renal sympathetic nerve activity (RSNA) induced by HS infusion. All experiments were performed in Wistar rats (280-350 g). A1 neurons were lesioned by microinjections of antidopamine-beta-hydroxylase-saporin (6.3 ng in 60 nl) into the CVLM (n=5), whereas sham rats received microinjections of free saporin (1.3 ng in 60 nl, n=10). Two weeks later, rats were anesthetized (urethane 1.2 g/kg, iv), and instrumented for recording of arterial pressure and RSNA. In sham rats, HS infusion (3 M NaCl, 0.18 ml/100 g bw, iv) induced a transient (=30 min) hypertension (peak at 10 min; 9+/-5 mm Hg) and a fall in RSNA (-32+/-7% of baseline at 10 min). A1-lesions increased the duration of the pressor response induced by HS infusion (16+/-2 mm Hg at 60 min) and abolished the fall in RSNA (-6+/-8% of baseline at 10 min). Catecholaminergic lesions extensions were confirmed by immunocytochemistry. Unilateral renal denervation reduced the renal vasodilatation induced by HS infusion (112+/-7% in denervated rats versus 127+/-4% in sham, 20 min after HS). These results suggest that A1 noradrenergic neurons are involved in the sympathoinhibition and consequent renal vasodilatation to acute changes in the extracellular fluid compartment.
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http://dx.doi.org/10.1016/j.autneu.2008.06.006 | DOI Listing |
Nat Commun
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Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, Jiangsu, China.
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Private Practice, Zubná Pohotovosť, s.r.o. Bratislava, Krížna 44, Slovakia.
Our review study addresses the issue of tooth loss, which is caused by loss of masticatory function and its impact on cognitive functions, dementia, and Alzheimer's disease. Numerous studies have confirmed a positive correlation between premature tooth loss, reduction in masticatory function and significant cognitive decline observed through learning disabilities, including overcoming ordinary life problems to early and advanced forms of dementia. Reduced numbers of teeth in the main food processing area, i.
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Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, Anhui, China.
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Univ. Angers, INSERM, CNRS, MITOVASC, Equipe CarME, SFR ICAT, 49000 Angers, France.
The vegetal alkaloid toxin veratridine (VTD) is a selective voltage-gated Na (Na) channel activator, widely used as a pharmacological tool in vascular physiology. We have previously shown that Na channels, expressed in arteries, contribute to vascular tone in mouse mesenteric arteries (MAs). Here, we aimed to better characterize the mechanisms of action of VTD using mouse cecocolic arteries (CAs), a model of resistance artery.
View Article and Find Full Text PDFNeurol Int
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Department of Human Studies, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
The purpose of this review is to compile and discuss available evidence in humans on the efficacy of YHM supplementation on performance in different exercise modalities. Yohimbine (YHM) is a naturally occurring alkaloid that induces increases in sympathetic nervous system (SNS) activation effectively initiating "fight or flight" responses. In supplement form, YHM is commonly sold as an isolated product or combined into multi-ingredient exercise supplements and is widely consumed in fitness settings despite the lack of empirical support until recently.
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