Brainstem projections of aortic baroreceptor afferent fibers in the rat

Ciriello, John

doi:10.1016/0304-3940(83)90482-2

Cited by 324 publications

(168 citation statements)

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“…Our own laboratory has suggested that the pathway may contribute to cerebral vasodilatation during hypertension and thus extend cerebrovascular autoregulation (Talman, W. T. et al, 1994), a suggestion that has been echoed by others in the field (Toda, N. and Okamura, T., 1992). We have shown that arterial baroreceptors are critical for cerebral vasodilatation when blood pressure has been raised beyond the autoregulatory range (Talman, W. T. et al, 1994;Talman, W. T. and Nitschke Dragon, D., 1995b;Talman, W. T. and Nitschke Dragon, D., 2002); that the NTS, where arterial baroreceptor fibers terminate in the central nervous system (Blessing, W. W. et al, 1999;Ciriello, J., 1983;Kalia, M. and Sullivan, J. M., 1982;Torrealba, F. and Claps, A., 1988), projects directly to the SSN (Agassandian, K. et al, 2002); that interruption of function at the level of SSN or pterygopalatine ganglia extends the autoregulatory range during hypertension as does baroreflex interruption (Agassandian, K. et al, 2003;Talman, W. T. and Nitschke Dragon, D., 2000), and that non-selective inhibition of synthesis of NO released by those ganglionic fibers had the same effect (Talman, W. T. and Nitschke Dragon, D., 1995a). These studies further suggest that nitroxidergic nerves projecting from the pterygopalatine ganglion to cerebral blood vessels play a roll in the increase in CBF seen in breakthrough (Talman, W. T. and Nitschke Dragon, D., 2000).…”

Section: Discussionmentioning

confidence: 99%

Neuronal nitric oxide mediates cerebral vasodilatation during acute hypertension

Talman

Dragon

2007

Brain Research

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Parasympathetic nerves from the pterygopalatine ganglia provide nitroxidergic innervation to forebrain cerebral blood vessels. Disruption of that innervation attenuates cerebral vasodilatation seen during acute hypertension as does systemic administration of a non-selective nitric oxide synthase (NOS) inhibitor. Although such studies suggest that nitric oxide (NO) released from parasympathetic nerves participates in vasodilatation of cerebral vessels during hypertension that hypothesis has not been tested with selective local inhibition of neuronal NOS (nNOS). We tested that hypothesis through these studies performed in anesthetized rats instrumented for continuous measurement of blood pressure, heart rate and pial arterial diameter through a cranial window. We sought to determine if the nNOS inhibitor propyl-L-arginine delivered directly to the outer surface of a pial artery would 1) attenuate changes in pial arterial diameter during acute hypertension and 2) block nNOS mediated dilator effects of N-methyl-D-Aspartate (NMDA) delivered into the window but 3) not block vasodilatation elicited by acetylcholine (ACh) and mediated by endothelial NOS dilator. Without the nNOS inhibitor arterial diameter abruptly increased 70 ± 15% when mean arterial pressure (MAP) reached 183 ± 3 mmHg while with nNOS inhibition diameter increased only 13 ± 10% (p<0.05) even when MAP reached 191 ± 4 (p>0.05). The nNOS inhibitor significantly attenuated vasodilatation induced by NMDA but not ACh delivered into the window. Thus, local nNOS inhibition attenuates breakthrough from autoregulation during hypertension as does complete interruption of the parasympathetic innervation of cerebral vessels. These findings further support the hypothesis that NO released from parasympathetic fibers contributes to cerebral vasodilatation during acute hypertension. Section: Regulatory Systems

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Section: Discussionmentioning

confidence: 99%

Neuronal nitric oxide mediates cerebral vasodilatation during acute hypertension

Talman

Dragon

2007

Brain Research

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“…This region of the NTS receives dense innervation from vagal afferents, including arterial baroreceptors (Ciriello, 1983;Mendelowitz et al, 1992), and also contains neurons that project to either CVLM or PVN (Weston et al, 2003;Hermes et al, 2006). Vagal afferent labeling was intense within ST, and varicose fibers were found in most subnuclei of NTS (Fig.…”

Section: Cranial Visceral Afferents Contact Nts Neurons Projecting Tomentioning

confidence: 98%

Cranial Visceral Afferent Pathways through the Nucleus of the Solitary Tract to Caudal Ventrolateral Medulla or Paraventricular Hypothalamus: Target-Specific Synaptic Reliability and Convergence Patterns

Bailey

Hermes

Andresen³

et al. 2006

J. Neurosci.

130

141

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Cranial visceral afferents activate central pathways that mediate systemic homeostatic processes. Afferent information arrives in the brainstem nucleus of the solitary tract (NTS) and is relayed to other CNS sites for integration into autonomic responses and complex behaviors. Little is known about the organization or nature of processing within NTS. We injected fluorescent retrograde tracers into two nuclei to identify neurons that project to sites involved in autonomic regulation: the caudal ventrolateral medulla (CVLM) or paraventricular nucleus of the hypothalamus (PVN). We found distinct differences in synaptic connections and performance in the afferent path through NTS to these neurons. Anatomical studies using confocal and electron microscopy found prominent, primary afferent synapses directly on somata and dendrites of CVLM-projecting NTS neurons identifying them as second-order neurons. In brainstem slices, afferent activation evoked large, constant latency EPSCs in CVLM-projecting NTS neurons that were consistent with the precise timing and rare failures of monosynaptic contacts on second-order neurons. In contrast, most PVN-projecting NTS neurons lacked direct afferent input and responded to afferent stimuli with highly variable, intermittently failing synaptic responses, indicating polysynaptic pathways to higher-order neurons. The afferent-evoked EPSCs in most PVN-projecting NTS neurons were smaller and unreliable but also often included multiple, convergent polysynaptic responses not observed in CVLM-projecting neurons. A few PVN-projecting NTS neurons had monosynaptic EPSC characteristics. Together, we found that cranial visceral afferent pathways are structured distinctly within NTS depending on the projection target. Such, intra-NTS pathway architecture will substantially impact performance of autonomic or neuroendocrine reflex arcs.

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“…GABA; cardiovascular; citrate synthase THE NUCLEUS OF THE SOLITARY tract (NTS) is the primary site in the central nervous system that receives the afferents arising from arterial baro-and chemoreceptors (10,15). The intermediate NTS receives inputs particularly from arterial baroreceptors, but some of these afferents achieve the commNTS (10,16).…”

mentioning

confidence: 99%

“…The intermediate NTS receives inputs particularly from arterial baroreceptors, but some of these afferents achieve the commNTS (10,16). The commNTS also receives inputs from arterial chemoreceptors, and seems to be highly sensitive to carotid chemoreceptor stimulation (8,9,11).…”

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confidence: 99%

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

Ogihara

Schoorlemmer

Levada

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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Ogihara CA, Schoorlemmer GHM, Levada AC, Pithon-Curi TC, Curi R, Lopes OU, Colombari E, Sato MA. Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats. Am J Physiol Regul Integr Comp Physiol 299: R291-R297, 2010. First published April 21, 2010 doi:10.1152/ajpregu.00055.2009.-Inhibition of the commissural nucleus of the solitary tract (commNTS) induces a fall in sympathetic nerve activity and blood pressure in spontaneously hypertensive rats (SHR), which suggests that this subnucleus of the NTS is a source of sympathoexcitation. Exercise training reduces sympathetic activity and arterial pressure. The purpose of the present study was to investigate whether the swimming exercise can modify the regional vascular responses evoked by inhibition of the commNTS neurons in SHR and normotensive Wistar-Kyoto (WKY) rats. Exercise consisted of swimming, 1 h/day, 5 days/wk for 6 wks, with a load of 2% of the body weight. The day after the last exercise session, the rats were anesthetized with intravenous ␣-chloralose, tracheostomized, and artificially ventilated. The femoral artery was cannulated for mean arterial pressure (MAP) and heart rate recordings, and Doppler flow probes were placed around the lower abdominal aorta and superior mesenteric artery. Microinjection of 50 mM GABA into the commNTS caused similar reductions in MAP in swimming and sedentary SHR (Ϫ25 Ϯ 6 and Ϫ30 Ϯ 5 mmHg, respectively), but hindlimb vascular conductance increased twofold in exercised vs. sedentary SHR (54 Ϯ 8 vs. 24 Ϯ 5%). GABA into the commNTS caused smaller reductions in MAP in swimming and sedentary WKY rats (Ϫ20 Ϯ 4 and Ϫ16 Ϯ 2 mmHg). Hindlimb conductance increased fourfold in exercised vs. sedentary WKY rats (75 Ϯ 2% vs. 19 Ϯ 3%). Therefore, our data suggest that the swimming exercise induced changes in commNTS neurons, as shown by a greater enhancement of hindlimb vasodilatation in WKY vs. SHR rats in response to GABAergic inhibition of these neurons.GABA; cardiovascular; citrate synthase THE NUCLEUS OF THE SOLITARY tract (NTS) is the primary site in the central nervous system that receives the afferents arising from arterial baro-and chemoreceptors (10, 15). The intermediate NTS receives inputs particularly from arterial baroreceptors, but some of these afferents achieve the commNTS (10, 16). The commNTS also receives inputs from arterial chemoreceptors, and seems to be highly sensitive to carotid chemoreceptor stimulation (8, 9, 11).The possible role of the commNTS as a source of sympathoexcitation was first shown by Nelson et al. (33), which demonstrated that nanoliter injections of L-glutamate into the commNTS evoke elevations in heart rate and arterial pressure mediated by the sympathetic nervous system. Electrolytic lesions or chemical inhibition of the commNTS have been shown to markedly decrease the splanchnic sympathetic nerve activity and arterial pressure in spontaneously hypertensive rats (SHR), which suggested that this subnucleus of the NTS contains neurons tonically active in S...

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Brainstem projections of aortic baroreceptor afferent fibers in the rat

Cited by 324 publications

References 20 publications

Neuronal nitric oxide mediates cerebral vasodilatation during acute hypertension

Neuronal nitric oxide mediates cerebral vasodilatation during acute hypertension

Cranial Visceral Afferent Pathways through the Nucleus of the Solitary Tract to Caudal Ventrolateral Medulla or Paraventricular Hypothalamus: Target-Specific Synaptic Reliability and Convergence Patterns

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

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