Stimulation of 5-HT2 receptors in the nucleus tractus solitarius enhances NMDA receptor-mediated reflex-evoked bradycardiac responses in the rat

Ndiaye, Awa; Sévoz‐Couche, Caroline; Nosjean, Anne; Hamon, Michel; Laguzzi, Raùl

doi:10.1016/s1566-0702(01)00318-6

Cited by 14 publications

(16 citation statements)

References 25 publications

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“…It has previously been established that microinjection of 5-HT 2 receptor agonists in the NTS induces hypotension and bradycardia (20,27) and that local administration of subthreshold doses only of such ligands can potentiate the cardiac response of the baroreflex (21). Therefore, it could be hypothesized that NTS 5-HT 2 receptors are key components in the hypotension, bradycardia, and enhanced cardiac baroreflex response occurring during IL or POA stimulation.…”

Section: Discussionmentioning

confidence: 99%

“…A single-barrel glass micropipette was lowered in the NTS at predetermined coordinates for chemical inhibition and for microinjections of vehicle or 5-HT 2 receptor antagonists (0.4 mm rostral and lateral to the calamus scriptorius and 0.4 mm beneath the dorsal surface of the medulla; see Ref. 21). The time interval between two symmetrical microinjections (100 nl) was Ͻ1 min.…”

Section: Procedures For Intra-nts Microinjectionsmentioning

confidence: 99%

“…In particular, serotonin (5-HT), through the stimulation of NTS 5-HT 2 receptors, produces hypotension (18) and a vagus nerve-mediated bradycardia (20,27,30). In addition, microinjections of 5-HT 2 receptor agonists in the NTS were shown to facilitate the baroreflex bradycardia induced by phenylephrine administration (21).…”

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confidence: 99%

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Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT_2Areceptors

Sévoz‐Couche¹,

Comet²,

Bernard³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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We previously showed that serotonin (5-HT2) receptor activation in the nucleus of the tractus solitarius (NTS) produced hypotension, bradycardia, and facilitation of the baroreflex bradycardia. Activation of the preoptic area (POA) of the hypothalamus, which is involved in shock-evoked passive behaviors, induces similar modifications. In addition, previous studies showed that blockade of the infralimbic (IL) part of the medial prefrontal cortex, which sends projections to POA, produced an inhibitory influence on the baroreflex cardiac response. Thus, to assess the possible implication of NTS 5-HT2 receptors in passive cardiovascular responses, we analyzed in anesthetized rats the effects of NTS inhibition and NTS 5-HT2 receptor blockade on the cardiovascular modifications induced by chemical (0.3 M D,L-homocysteic acid) and electrical (50 Hz, 150-200 microA) stimulation of IL or POA. Intra-NTS microinjections of muscimol, a GABAA receptor agonist, prevented the decreases in blood pressure and heart rate normally evoked by IL or POA activation. In addition, we found that intra-NTS microinjection of R(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine-methanol, a specific 5-HT2A receptor antagonist, did not affect the decreases in cardiovascular baseline parameters induced by IL or POA stimulation but prevented the facilitation of the aortic baroreflex bradycardia normally observed during IL (+65 and +60%) or POA (+70 and +69%) electrical and chemical stimulation, respectively. These results show that NTS 5-HT2A receptors play a key role in the enhancement of the cardiac response of the baroreflex but not in the changes in basal heart rate and blood pressure induced by IL or POA stimulation.

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Section: Discussionmentioning

confidence: 99%

Section: Procedures For Intra-nts Microinjectionsmentioning

confidence: 99%

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Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT_2Areceptors

Sévoz‐Couche¹,

Comet²,

Bernard³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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“…This led us to speculate that the nonselective double blockage of 5-HT 2A /5-HT 2C receptors by the drug might contribute to the process, a view that is corroborated by the information that both the 5-HT 2A and the 5-HT 2B receptors exert opposing effects on neurons of the NTS (12). We should mention a pioneering study by N'Diaye et al (22), showing that DOI, a non-selective 5-HT 2 receptor agonist, when microinjected into the NTS of rats, enhanced NMDA receptor-mediated reflex bradycardia. These results agree with our hypothesis that 5-HT 2A receptors facilitate the reflex control of heart rate, although the animals were not beta-blocked as in the present study.…”

Section: Discussionmentioning

confidence: 77%

Central 5-HT2A receptors modulate the vagal bradycardia in response to activation of the von Bezold-Jarisch reflex in anesthetized rats

Neto

Macêdo

Silva

et al. 2011

Braz J Med Biol Res

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“…Actually, the NTS does contain several types of functional 5-HT receptors. In particular, the pharmacological stimulation of NTS 5-HT 2 receptors is known to facilitate the cardiac component of the baroreflex [133]. On the other hand, 5-HT 3 receptor stimulation in the NTS has been reported to drastically affect the reflex control of heart activity [126,184].…”

Section: Introductionmentioning

confidence: 99%

The Key Role of Medullary 5-HT3 Receptors in the Serotonin-Mediated Neural Control of Cardiovascular Function

Sévoz‐Couche¹,

Machado²,

Hamon³

et al. 2005

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The baroreceptor reflex plays a crucial role in the homeostatic control of cardiovascular parameters. In the central nervous system, the nucleus of the tractus solitarius (NTS) is critically involved in cardiovascular reflex control because it is both the first site of termination of glutamatergic baroreceptor afferent fibres and an important integrative area for the sensory afferent signals reaching the brainstem. In addition to glutamate, the NTS contains numerous neurotransmitters that could participate in the modulations of the baroreceptor reflex sensitivity which occur under various physiological conditions. In particular, a large body of evidence indicates that serotonin plays a modulatory role in the central control of blood pressure, especially at the level of the NTS, which is innervated by both central and peripheral serotonergic fibres. Indeed, serotonin exerts multiple cardiovascular influences through the activation of several receptors in the NTS. Actually, the NTS is the central area endowed with the highest density of serotonin 3 (5-HT 3 ) receptors whose stimulation triggers all the adaptive cardiovascular changes normally associated with behavioural responses to various stressful conditions.In this review, we first assess the current knowledge about the mechanisms underlying the cardiovascular effects of the specific activation of serotonergic receptors in the NTS. Secondly, we describe evidence that, in the NTS, 5-HT 3 receptors play a key role in one of the crucial homeostatic responses that characterise the defence reaction: the inhibitory modulation of the parasympathetic cardiac component of the baroreceptor reflex. The possible functional interactions of 5-HT 3 receptors with GABA A , NK 1 and NMDA receptors within the NTS are also discussed.

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Stimulation of 5-HT2 receptors in the nucleus tractus solitarius enhances NMDA receptor-mediated reflex-evoked bradycardiac responses in the rat

Cited by 14 publications

References 25 publications

Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT_2Areceptors

Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT_2Areceptors

Central 5-HT2A receptors modulate the vagal bradycardia in response to activation of the von Bezold-Jarisch reflex in anesthetized rats

The Key Role of Medullary 5-HT3 Receptors in the Serotonin-Mediated Neural Control of Cardiovascular Function

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Stimulation of 5-HT2 receptors in the nucleus tractus solitarius enhances NMDA receptor-mediated reflex-evoked bradycardiac responses in the rat

Cited by 14 publications

References 25 publications

Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT2Areceptors

Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT2Areceptors

Central 5-HT2A receptors modulate the vagal bradycardia in response to activation of the von Bezold-Jarisch reflex in anesthetized rats

The Key Role of Medullary 5-HT3 Receptors in the Serotonin-Mediated Neural Control of Cardiovascular Function

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Product

Resources

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Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT_2Areceptors

Cardiac baroreflex facilitation evoked by hypothalamus and prefrontal cortex stimulation: role of the nucleus tractus solitarius 5-HT_2Areceptors