Identification of branching paraventricular neurons of the hypothalamus that project to the rostroventrolateral medulla and spinal cord

Pyner, Susan; Coote, John H.

doi:10.1016/s0306-4522(00)00283-9

Cited by 257 publications

(205 citation statements)

References 40 publications

Supporting

Mentioning

193

Contrasting

Unclassified

Order By: Relevance

“…Level 3 was the most caudal and consisted of the medial parvocellular (MP) and lateral parvocellular (LP) divisions. Based on previous anatomical studies in our laboratory (Stocker et al, 2004a) and others (Pyner and Coote, 2000), these levels of the PVH contain the highest density of neurons with projections to the RVLM. Counts of labeled neurons at each level and subnucleus were performed in one section per animal.…”

Section: Antibody Characterizationsmentioning

confidence: 80%

“…Anatomical considerations indicate that PVH neurons can influence sympathetic preganglionic neurons via either mono-or poly-synaptic pathways (Saper et al, 1976;Swanson and Kuypers, 1980;Strack et al, 1989;Shafton et al, 1999;Pyner and Coote, 2000;Cano et al, 2001;Stocker et al, 2004a). However, PVH is heterogeneous and controls many types of sympathetic efferents besides vasomotor.…”

Section: Most Rvlm-projecting Pvh Neurons Are Glutamatergicmentioning

confidence: 99%

See 1 more Smart Citation

Water deprivation activates a glutamatergic projection from the hypothalamic paraventricular nucleus to the rostral ventrolateral medulla

Stocker

Simmons

Stornetta

et al. 2005

J of Comparative Neurology

122

133

View full text Add to dashboard Cite

Elevated sympathetic outflow contributes to the maintenance of blood pressure in water-deprived rats. The neural circuitry underlying this response may involve activation of a pathway from the hypothalamic paraventricular nucleus (PVH) to the rostral ventrolateral medulla (RVLM). We sought to determine whether the PVH-RVLM projection activated by water deprivation is glutamatergic and/or contains vasopressin-or oxytocin-neurophysins. Vesicular glutamate transporter2 (VGLUT2) mRNA was detected by in situ hybridization in the majority of PVH neurons retrogradely labeled from the ipsilateral RVLM with cholera-toxin subunit B (CTB; 85% on average with regional differences). Very few RVLM-projecting PVH neurons were immunoreactive for oxytocin-or vasopressin-associated neurophysin. Injection of biotinylated dextran amine (BDA) into the PVH produced clusters of BDA-positive nerve terminals within the ipsilateral RVLM that were immunoreactive (ir) for the VGLUT2 protein. Some of these terminals made close appositions with tyrosine-hydroxylase-ir dendrites (presumptive C1 cells). In waterdeprived rats (n=4), numerous VGLUT2 mRNA-positive PVH neurons retrogradely labeled from the ipsilateral RVLM with CTB were c-Fos-ir (16-40% depending on PVH region). In marked contrast, few glutamatergic, RVLM-projecting PVH neurons were c-Fos-ir in control rats (n=3; 0-3% depending on PVH region). Most (94 ± 4%) RVLM-projecting PVH neurons activated by water deprivation contained VGLUT2 mRNA. In summary, the majority of PVH neurons that innervate the RVLM are glutamatergic and this population includes the neurons that are activated by water deprivation. One mechanism by which water deprivation may increase the sympathetic outflow is the activation of a glutamatergic pathway from the PVH to the RVLM.

show abstract

Section: Antibody Characterizationsmentioning

confidence: 80%

Section: Most Rvlm-projecting Pvh Neurons Are Glutamatergicmentioning

confidence: 99%

Water deprivation activates a glutamatergic projection from the hypothalamic paraventricular nucleus to the rostral ventrolateral medulla

Stocker

Simmons

Stornetta

et al. 2005

J of Comparative Neurology

122

133

View full text Add to dashboard Cite

show abstract

“…PVN neurons project to the RVLM, NTS, and intermediolateral cell column of the spinal cord. 29 Michelini 30 and Jackson et al 31 demonstrated that the oxytocinergic and vasopresinergic projections from the PVN to the NTS were enhanced after EX, which might change neuronal activity in the NTS. A previous study has shown that EX downregulates AT 1 R mRNA expression in central cardiovascular regulatory regions, such as the PVN, the NTS, and the RVLM, in CHF animals.…”

Section: Discussionmentioning

confidence: 99%

Exercise Training Prevents Arterial Baroreflex Dysfunction in Rats Treated With Central Angiotensin II

et al. 2007

View full text Add to dashboard Cite

Abstract-Angiotensin II (Ang II)-induced arterial baroreflex dysfunction is associated with superoxide generation in the brain. Exercise training (EX) improves baroreflex function and decreases oxidative stress in cardiovascular diseases linked to elevated central Ang II. The aim of this study was to determine whether previous EX prevents baroreflex impairment caused by central administration of exogenous Ang II via an Ang II-superoxide mechanism. Four groups of rats were used: non-EX artificial cerebrospinal fluid infused, non-EX Ang II infused, EX artificial cerebrospinal fluid infused, and EX Ang II infused. Rats were treadmill trained for 3 to 4 weeks and subjected to intracerebroventricular infusion of Ang II over the last 3 days of EX. Twenty-four hours after the end of EX, the arterial baroreflex was assessed in anesthetized rats. Key Words: exercise Ⅲ baroreflex Ⅲ sympathetic nerve activity Ⅲ reactive oxygen species Ⅲ AT 1 receptor I mpairment of arterial baroreflex function is an important feature in cardiovascular diseases, such as chronic heart failure (CHF) and hypertension. 1,2 This abnormality increases cardiovascular risk. 3 Recent studies indicate that the blunted arterial baroreflex is related to an enhanced central angiotensin II (Ang II) mechanism, because blockade of Ang II type 1 receptors (AT 1 Rs) in the brain restored baroreflex sensitivity. 4 Intracerebroventricular (icv) infusion of Ang II depresses arterial baroreflex function in normal animals. 5 However, specific brain nuclei and the intracellular mechanism for Ang II-induced baroreflex dysfunction have not been fully identified. The paraventricular nucleus (PVN) of the hypothalamus plays an important role in the control of baroreflex function and sympathetic drive. 6 Furthermore, the PVN contains a high density of AT 1 R 7 and is a candidate region to respond to Ang II in the cerebrospinal fluid. 8 Several lines of evidence show that reduced nicotinamideadenine dinucleotide phosphate (NAD[P]H) oxidase-derived reactive oxygen species (ROS) are novel mediators of Ang II signaling in the central nervous system. 9 Pretreatment with adenoviral-mediated superoxide dismutase prevents Ang IIinduced hypertension and the increased superoxide production. 10 On the other hand, the AT 1 R antagonist losartan abolishes Ang II-stimulated superoxide generation. 9 Increases in superoxide production may contribute to impaired arterial baroreflex function. 5,11 Conversely, antioxidant treatment improves baroreflex sensitivity. 11 Exercise training (EX) has been demonstrated to alter neural control of the circulation, including influencing arterial baroreflex function. 12 Although the effects of EX on baroreflex function in normal subjects and animals are increased, 12 decreased, 13,14 or unchanged, 15 EX consistently increases baroreflex sensitivity in CHF and hypertensive subjects. 16 -18 The mechanisms responsible for the training-induced improvement of baroreflex function involve changes in central and peripheral components of the baroreflex arc....

show abstract

“…Because anatomical studies have shown that 15-20% of RVLM-projecting PVN neurons have branched axons that also target the IML (Pyner and Coote 2000;Shafton et al 1998;Stocker et al 2006), one would expect that a reasonably large sample of cells antidromically activated from the spinal cord would include at least some neurons with branched axons that also innervate the RVLM. This being the case, one would expect that some group I or group II neurons from our previous study should have had properties nearly identical to those of PVN-RVLM/IML neurons in the present study.…”

Section: Pvn-rvlm and Pvn-rvlm/iml Neurons And Support Of Sympatheticmentioning

confidence: 99%

“…One group monosynaptically targets the spinal intermediolateral cell column (IML; PVN-IML), the location of sympathetic preganglionic neurons (Saper et al 1976;Swanson and Sawchenko 1980). Another group innervates presympathetic neurons in the rostral ventrolateral medulla (RVLM; PVN-RVLM) (Pyner and Coote 2000;Shafton et al 1998;Stocker et al 2006;Swanson and Sawchenko 1980). A third and more recently identified group has branched axons that innervate both the RVLM and IML (PVN-RVLM/IML) (Pyner and Coote 2000;Shafton et al 1998;Stocker et al 2004a).…”

Section: Introductionmentioning

confidence: 99%

In Vivo Discharge Properties of Hypothalamic Paraventricular Nucleus Neurons With Axonal Projections to the Rostral Ventrolateral Medulla

Chen

Toney

2010

Journal of Neurophysiology

View full text Add to dashboard Cite

Chen Q-H, Toney GM. In vivo discharge properties of hypothalamic paraventricular nucleus neurons with axonal projections to the rostral ventrolateral medulla. J Neurophysiol 103: 4 -15, 2010. First published November 4, 2009 doi:10.1152/jn.00094.2009. The hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) are key components of a neural network that generates and regulates sympathetic nerve activity (SNA). Although each region has been extensively studied, little is presently known about the in vivo discharge properties of individual PVN neurons that directly innervate the RVLM. Here extracellular recording was performed in anesthetized rats, and antidromic stimulation was used to identify single PVN neurons with axonal projections to the RVLM (n ϭ 94). Neurons were divided into two groups that had either unbranched axons terminating in the RVLM (i.e., PVN-RVLM neurons, n ϭ 65) or collateralized axons targeting both the RVLM and spinal cord [i.e., PVN-RVLM/ intermediolateral cell column (IML) neurons, n ϭ 29]. Many PVN-RVLM (32/65, 49%) and PVN-RVLM/IML (17/29, 59%) neurons were spontaneously active. The average firing frequency was not different across groups. Spike-triggered averaging revealed that spontaneous discharge of most neurons was temporally correlated with renal SNA (PVN-RVLM: 12/21, 57%; PVN-RVLM/IML: 6/9, 67%). Time histograms triggered by the electrocardiogram (ECG) R-wave indicated that discharge of most cells was also cardiac rhythmic (PVN-RVLM: 25/32, 78%; PVN-RVLM/IML: 10/17, 59%). Raising and lowering arterial blood pressure to increase and decrease arterial baroreceptor input caused a corresponding decrease and increase in firing frequency among cells of both groups (PVN-RVLM: 9/13, 69%; PVN-RVLM/IML: 4/4, 100%). These results indicate that PVN-RVLM and PVN-RVLM/IML neurons are both capable of contributing to basal sympathetic activity and its baroreflex modulation.

show abstract

Identification of branching paraventricular neurons of the hypothalamus that project to the rostroventrolateral medulla and spinal cord

Cited by 257 publications

References 40 publications

Water deprivation activates a glutamatergic projection from the hypothalamic paraventricular nucleus to the rostral ventrolateral medulla

Water deprivation activates a glutamatergic projection from the hypothalamic paraventricular nucleus to the rostral ventrolateral medulla

Exercise Training Prevents Arterial Baroreflex Dysfunction in Rats Treated With Central Angiotensin II

In Vivo Discharge Properties of Hypothalamic Paraventricular Nucleus Neurons With Axonal Projections to the Rostral Ventrolateral Medulla

Contact Info

Product

Resources

About