Microvascular specializations promoting rapid interstitial solute dispersion in nucleus tractus solitarius

Gross, Paul M.; Wall, Katharine M.; Pang, Judith J.; Shaver, Steven W.; Wainman, Dan S.

doi:10.1152/ajpregu.1990.259.6.r1131

Cited by 147 publications

(134 citation statements)

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“…It should also be noted that gastrointestinal hormones released into the circulation could affect brainstem function independent of primary afferent nerves by acting directly on neurons in the area postrema and NTS. Both these structures have a weak or absent blood brain barrier (Gross et al, 1990) (Gross et al, 1991). Since dendrites of vagal motor neurons penetrate deep into the NTS, they could also be directly affected by circulating factors.…”

Section: Vagal and Other Autonomic Hindbrain Mechanisms Involved In Fmentioning

confidence: 99%

The vagus nerve, food intake and obesity

Berthoud

2008

Regulatory Peptides

265

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Food interacts with sensors all along the alimentary canal to provide the brain with information regarding its composition, energy content, and beneficial effect. Vagal afferents innervating the gastrointestinal tract, pancreas, and liver provide a rapid and discrete account of digestible food in the alimentary canal, as well as circulating and stored fuels, while vagal efferents together with the sympathetic nervous system and hormonal mechanisms codetermine the rate of nutrient absorption, partitioning, storage, and mobilization. Although vagal sensory mechanisms play a crucial role in the neural mechanism of satiation, there is little evidence suggesting a significant role in long-term energy homeostasis. However, increasing recognition of vagal involvement in the putative mechanisms making bariatric surgeries the most effective treatment for obesity should greatly stimulate future research to uncover the many details regarding the specific transduction mechanisms in the periphery and the inter-and intra-neuronal signaling cascades disseminating vagal information across the neuraxis.

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Section: Vagal and Other Autonomic Hindbrain Mechanisms Involved In Fmentioning

confidence: 99%

The vagus nerve, food intake and obesity

Berthoud

2008

Regulatory Peptides

265

199

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“…In the nucleus tractus solitarius (NTS) we identified a specialized subpopulation of neurons that express both HSD2 and MR (Geerling et al, 2006). The distribution of these neurons overlaps a blood-brain barrier-deficient (BBB-deficient) zone within the NTS (Gross et al, 1990). This location could allow them special access to blood-borne aldosterone, which has been reported to penetrate the BBB much less than other steroids (Pardridge and Mietus, 1979;Funder and Myles, 1996).…”

Section: Introductionmentioning

confidence: 97%

Aldosterone Target Neurons in the Nucleus Tractus Solitarius Drive Sodium Appetite

Geerling¹,

Engeland²,

Kawata³

et al. 2006

J. Neurosci.

135

187

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Sodium appetite can be enhanced by the adrenal steroid aldosterone via an unknown brain mechanism. A novel group of neurons in the nucleus tractus solitarius expresses the enzyme 11-␤-hydroxysteroid dehydrogenase type 2, which makes them selectively responsive to aldosterone. Their activation parallels sodium appetite in different paradigms of salt loss even in the absence of aldosterone. These unique aldosterone target neurons may represent a previously unrecognized central convergence point at which hormonal and neural signals can be integrated to drive sodium appetite.

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“…PGH 2 in turn is converted to PGE 2 by the enzyme PGE 2 synthase (Thoren et al 2003). In addition to localized formation in the CNS, PGE 2 is synthesized outside the CNS and can reach NTS neurons because this area of the brain lacks a complete bloodbrain barrier (Gross et al 1990). …”

mentioning

confidence: 99%

Prostaglandin E2 depresses solitary tract-mediated synaptic transmission in the nucleus tractus solitarius

Laaris¹,

Weinreich²

2007

Neuroscience

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Prostaglandin E 2 (PGE 2 ) is a prototypical inflammatory mediator that excites and sensitizes cell bodies (Kwong and Lee, 2002; and peripheral nerve terminals (Ho et al. 2000) of primary vagal sensory neurons. Nearly all central nerve terminals of vagal afferents are in the nucleus tractus solitarius (NTS), where they operate with a high probability of release (Doyle and Andresen, 2001). We studied the effect of PGE 2 on synaptic transmission between tractus solitarius afferent nerve terminals and the second order NTS neurons in brain stem slices of Sprague Dawley rats. Whole-cell patch recording in voltage clamp mode was used to study evoked excitatory postsynaptic glutamatergic currents (evEPSCs) from NTS neurons elicited by electrical stimulation of the solitary tract (ST). In 34 neurons, bath applied PGE 2 (200 nM) decreased the evEPSC amplitude by 49 ± 5 %. In 22 neurons, however, PGE 2 had no effect. We also tested 15 NTS neurons for capsaicin sensitivity. Seven neurons generated evEPSCs that were equally unaffected by PGE 2 and capsaicin. Conversely, evEPSCs of the other 8 neurons, which were PGE 2 -responsive, were abolished by 200 nM capsaicin. Furthermore, the PGE 2-induced depression of evEPSCs was associated with an increase in the paired pulse ratio and a decrease in both the frequency and amplitude of the spontaneous excitatory postsynaptic currents (sEPSCs) and TTX-independent spontaneous miniature excitatory postsynaptic currents (mEPSCs). These results suggest that PGE 2 acts both presynaptically on nerve terminals and postsynaptically on NTS neurons to reduce glutamatergic responses. KeywordsGlutamate; AMPA receptors; Presynaptic; Postsynaptic Many neurons in the nucleus of the tractus solitarius (NTS) receive nerve terminals whose axons arise from cell bodies of vagal primary afferent neurons located in the nodose and jugular vagal ganglia. These primary vagal afferents convey diverse sensory information from a variety of receptors located in cardiovascular, respiratory, gastrointestinal and other organs to the NTS neurons in the medulla (Contreras, 1982). Thus, the first monosynaptic contact for myelinated A-type and unmyelinated C-type axons of primary vagal afferent fibers are the second-order neurons in the NTS. These fibers reach second-order NTS neurons via the solitary tract (Doyle Corresponding author: Nora Laaris, Department Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, Tel: (410) 706-1409, Fax: (410) 706-0032, e-mail: nlaar001@umaryland.edu. Section Editor: Dr. Yoland Smith, Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA 30329, USA Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its fin...

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Microvascular specializations promoting rapid interstitial solute dispersion in nucleus tractus solitarius

Cited by 147 publications

References 0 publications

The vagus nerve, food intake and obesity

The vagus nerve, food intake and obesity

Aldosterone Target Neurons in the Nucleus Tractus Solitarius Drive Sodium Appetite

Prostaglandin E2 depresses solitary tract-mediated synaptic transmission in the nucleus tractus solitarius

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