The central organization of carotid body afferent projections to the brainstem of the rat

Finley, James C. W.; Katz, David M.

doi:10.1016/0006-8993(92)90458-l

Cited by 378 publications

(274 citation statements)

References 41 publications

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“…Although the reasons for this discrepancy are not known, it may be related to the large volumes and dosages of Hcrt-1 used in these previous studies (4,39,40), because they were several orders of magnitude greater than those used in the present experiments. In fact, in this study, at the higher dosages of Hcrt-1, small pressor responses could be elicited on occasion from some sites in the caudal Com region of NTS, a region of the NTS shown to receive predominantly chemoreceptor afferent fiber projections (7,16).…”

Section: Discussionmentioning

confidence: 51%

“…In addition, the caudal Sm and Com has been shown to be densely innervated by afferents arising from carotid chemoreceptors (16). This suggests the possibility that Hcrt-1 neurons in the lateral hypothalamus may have a prominent role in the modulation of the cardiovascular responses evoked by the activation of baroreceptor and/or chemoreceptor reflexes.…”

Section: Discussionmentioning

confidence: 99%

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Cardiovascular effects of hypocretin-1 in nucleus of the solitary tract

Oliveira

Rosas‐Arellano

Solano-Flores

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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lar effects of hypocretin-1 in nucleus of the solitary tract. Am J Physiol Heart Circ Physiol 284: H1369-H1377, 2003. First published December 12, 2002 10.1152/ajpheart.00877.2002Experiments were done in male Wistar rats to investigate the effects of microinjection of hypocretin-1 (Hcrt-1) into the nucleus of the solitary tract (NTS) on mean arterial pressure (MAP), heart rate (HR), and the baroreflex. In the first series, the distribution of Hcrt-1-like immunoreactivity (Ir) was mapped within the region of NTS. Hcrt-1 Ir was found throughout the NTS region, predominantly within the caudal dorsolateral (Slt), medial (Sm), and interstitial subnuclei of the NTS. In the second series, in ␣-chloralose or urethaneanesthetized rats, microinjection of Hcrt-1 (0.5-5 pmol) into the caudal NTS elicited a dose-dependent decrease in MAP and HR. A mapping of the caudal NTS region showed that the largest depressor and bradycardia responses elicited by Hcrt-1 were from sites in the Slt and Sm. In addition, doses Ͼ2.5 pmol at a small number of sites localized to the caudal commissural nucleus of NTS elicited pressor and tachycardia responses. Intravenous administration of the muscarinic receptor blocker atropine methyl bromide abolished the bradycardia response and attenuated the depressor response, whereas subsequent administration of the nicotinic receptor blocker hexamethonium bromide abolished the remaining MAP response. Finally, microinjection of Hcrt-1 into the NTS significantly potentiated the reflex bradycardia to activation of arterial baroreceptors as a result of increasing MAP by systemic injections of phenylephrine (2-4 g/kg). These results suggest that Hcrt-1 in the NTS activates neuronal circuits that increases vagal activity to the heart, inhibits sympathetic activity to the heart and vasculature, and alters the excitability of NTS neuronal circuits that reflexly control the circulation.orexin-A; blood pressure; baroreceptor reflex; brain stem; ingestive behavior HYPOCRETIN (Hcrt) neuropeptides have been recently shown to be almost exclusively expressed within neurons of the lateral and perifornical hypothalamic areas (30,33,35,47,49). These peptides, Hcrt-1, a 33 amino-acid peptide with an NH 2 -terminal pyrogutalmyl residue, and Hcrt-2, a 28 amino acid peptide with a COOH-terminal amide (35), are de-

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Section: Discussionmentioning

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Cardiovascular effects of hypocretin-1 in nucleus of the solitary tract

Oliveira

Rosas‐Arellano

Solano-Flores

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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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%

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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“…The visceral afferents arising from various kinds of receptors carry a wide range of information about the status of the cervico-abdominal organs including gastric load [1], esophageal tension [2,3], lung volume [4-6], arterial blood pressure [7], chemosensory inputs from the carotid bodies [8] and intragastric concentrations of bioactive substances [1,9]. Compared to somatosensory sensation that reports rapid touch pressure changes and acute nociceptive information, these sets of visceral information are encoded in a long-lasting and slowly changing frequency-modulated series of action potentials and transmitted to the brain via primary afferent fibers that pass through the vagus and glossopharyngeal nerves.…”

Section: Introductionmentioning

confidence: 99%

Distinct target cell-dependent forms of short-term plasticity of the central visceral afferent synapses of the rat

et al. 2010

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Background The visceral afferents from various cervico-abdominal sensory receptors project to the dorsal vagal complex (DVC), which is composed of the nucleus of the solitary tract (NTS), the area postrema and the dorsal motor nucleus of the vagus nerve (DMX), via the vagus and glossopharyngeal nerves and then the solitary tract (TS) in the brainstem. While the excitatory transmission at the TS-NTS synapses shows strong frequency-dependent suppression in response to repeated stimulation of the afferents, the frequency dependence and short-term plasticity at the TS-DMX synapses, which also transmit monosynaptic information from the visceral afferents to the DVC neurons, remain largely unknown. Results Recording of the EPSCs activated by paired or repeated TS stimulation in the brainstem slices of rats revealed that, unlike NTS neurons whose paired-pulse ratio (PPR) is consistently below 0.6, the distribution of the PPR of DMX neurons shows bimodal peaks that are composed of type I (PPR, 0.6-1.5; 53% of 120 neurons recorded) and type II (PPR, < 0.6; 47%) neurons. Some of the type I DMX neurons showed paired-pulse potentiation. The distinction of these two types depended on the presynaptic release probability and the projection target of the postsynaptic cells; the distinction was not dependent on the location or soma size of the cell, intensity or site of the stimulation, the latency, standard deviation of latency or the quantal size. Repeated stimulation at 20 Hz resulted in gradual and potent decreases in EPSC amplitude in the NTS and type II DMX neurons, whereas type I DMX neurons displayed only slight decreases, which indicates that the DMX neurons of this type could be continuously activated by repeated firing of primary afferent fibers at a high (~10 Hz) frequency. Conclusions These two general types of short-term plasticity might contribute to the differential activation of distinct vago-vagal reflex circuits, depending on the firing frequency and type of visceral afferents.

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The central organization of carotid body afferent projections to the brainstem of the rat

Cited by 378 publications

References 41 publications

Cardiovascular effects of hypocretin-1 in nucleus of the solitary tract

Cardiovascular effects of hypocretin-1 in nucleus of the solitary tract

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

Distinct target cell-dependent forms of short-term plasticity of the central visceral afferent synapses of the rat

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