Commissural NTS contributes to pressor responses to glutamate injected into the medial NTS of awake rats

Colombari, Eduardo; Menani, José Vanderlei; Talman, William T.

doi:10.1152/ajpregu.1996.270.6.r1220

Cited by 63 publications

(91 citation statements)

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“…Lesions were restricted to the commNTS, leaving intact the mNTS, hypoglossus nucleus (XII), and the AP. The size and the position of the lesions were similar to those in our earlier studies (27,28).…”

Section: Discussionsupporting

confidence: 88%

“…The role of the NTS, including the commNTS, in the control of the cardiovascular reflexes has been extensively studied (18)(19)(20)27). The new finding of the present study is that the commNTS also contributes to water intake control and may represent an essential step in the neural pathways involved in the regulation of water intake induced by sc isoproterenol.…”

Section: Discussionmentioning

confidence: 58%

“…However, the NTS exerts a differential control on the cardiovascular reflexes. While mNTS lesions block the baroreflex (29), commNTS lesions do not change the baroreflex (27). Because of this, commNTS lesions more likely affect cardiopulmonary signals than baroreceptor signals.…”

Section: Discussionmentioning

confidence: 99%

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Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

Blanch

Freiria-Oliveira

Colombari

et al. 2007

Braz J Med Biol Res

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The nucleus of the solitary tract (NTS) is the primary site of the cardiovascular afferent information about arterial blood pressure and volume. The NTS projects to areas in the central nervous system involved in cardiovascular regulation and hydroelectrolyte balance, such as the anteroventral third ventricle region and the lateral parabrachial nucleus. The aim of the present study was to investigate the effects of electrolytic lesion of the commissural NTS on water and 0.3 M NaCl intake and the cardiovascular responses to subcutaneous injection of isoproterenol. Male Holtzman rats weighing 280 to 320 g were submitted to sham lesion or electrolytic lesion of the commissural NTS (N = 6-15/group). The sham-lesioned rats had the electrode placed along the same coordinates, except that no current was passed. Water intake induced by subcutaneous isoproterenol (30 µg/kg body weight) significantly increased in chronic (15 days) commissural NTS-lesioned rats (to 2.4 ± 0.2 vs sham: 1.9 ± 0.2 mL 100 g body weight -1 60 min -1 ). Isoproterenol did not induce any sodium intake in sham or in commissural NTS-lesioned rats. The isoproterenol-induced hypotension (sham: -27 ± 4 vs commissural NTS-lesioned rats: -22 ± 4 mmHg/20 min) and tachycardia (sham: 168 ± 10 vs commissural NTS: 144 ± 24 bpm/20 min) were not different between groups. The present results suggest that the commissural NTS is part of an inhibitory neural pathway involved in the control of water intake induced by subcutaneous isoproterenol, and that the overdrinking observed in lesioned rats is not the result of a cardiovascular imbalance in these animals.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 58%

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Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

Blanch

Freiria-Oliveira

Colombari

et al. 2007

Braz J Med Biol Res

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“…Lesions virtually destroyed the commissural NTS completely but did not affect the area postrema or lateral regions of the NTS. The extent of the lesions was similar to that observed in our earlier studies (13)(14)(15)(16). Only rats whose lesion sites were located in the commissural NTS were considered for data analysis.…”

Section: Resultssupporting

confidence: 90%

Changes in sodium appetite evoked by lesions of the commissural nucleus of the tractus solitarius

Ogihara

Schoorlemmer

Colombari

et al. 2009

Braz J Med Biol Res

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Ablation of the area postrema/caudal nucleus of the tractus solitarius (NTS) complex increases sodium intake, but the effect of selective lesions of the caudal NTS is not known. We measured depletion-induced sodium intake in rats with electrolytic lesions of the commissural NTS that spared the area postrema. One day after the lesion, rats were depleted of sodium with furosemide (10 mg/kg body weight, sc ) and then had access to water and a sodium-deficient diet for 24 h when 1.8% NaCl was offered. Water and saline intakes were measured for 2 h. Saline intake was higher in lesioned than in sham-lesioned rats (mean ± SEM: 20 ± 2 vs 11 ± 3 mL/2 h, P < 0.05, N = 6-7). Saline intake remained elevated in lesioned rats when the tests were repeated 6 and 14 days after the lesion, and water intake in these two tests was increased as well. Water intake seemed to be secondary to saline intake both in lesioned and in sham-lesioned rats. A second group of rats was offered 10% sucrose for 2 h/day before and 2, 7, and 15 days after lesion. Sucrose intake in lesioned rats was higher than in sham-lesioned rats only 7 days after lesioning. A possible explanation for the increased saline intake in rats with commissural NTS lesions could be a reduced gastrointestinal feedback inhibition. The commissural NTS is probably part of a pathway for inhibitory control of sodium intake that also involves the area postrema and the parabrachial nucleus.

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“…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).…”

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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Commissural NTS contributes to pressor responses to glutamate injected into the medial NTS of awake rats

Cited by 63 publications

References 0 publications

Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

Changes in sodium appetite evoked by lesions of the commissural nucleus of the tractus solitarius

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

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