The pattern of excitatory inputs to the nucleus tractus solitarii evoked on stimulation in the hypothalamic defence area in the cat.

Silva-Carvalho, L; Dawid-Milner, Marc Stefan; Spyer, K. M.

doi:10.1113/jphysiol.1995.sp020913

Cited by 34 publications

(27 citation statements)

References 17 publications

(35 reference statements)

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“…Secondly, multiple direct pathways connect the HDA to the NTS. For instance, in cat, stimulation of the HDA elicits monosynaptic excitatory [11] and inhibitory [10] postsynaptic potentials in NTS neurons that receive inputs from baroreceptors. Thirdly, HDA stimulation elicits rapid adenosine release in the NTS derived from extracellular ATP [20], presumably eliciting a β-adrenergic iliac vasodilation that is overridden by a vasopressinergic vasoconstriction [41,42].…”

Section: Hindlimb Vasodilation In Alerting-defense Responses Is Mediamentioning

confidence: 99%

“…Identified projections from HDA neurons to the rostral ventrolateral medulla (RVLM) and nucleus tractus solitarius (NTS) suggest that cardiovascular responses elicited by hypothalamic stimulation are mediated in the medulla [7][8][9]. Stimulation of the HDA produces excitatory post-synaptic potentials in neurons at the intermediate NTS of cat [10,11]; suggesting that the resulting rise in peripheral HVC can derive from activation of sympathoinhibitory pathways involved in the baroreflex. In rat, electrical stimulation of the HDA increases the firing rate of neurons in the RVLM that are barosensitive and bulbospinal [12], presumably resulting in decrease of peripheral HVC.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Korim

Ferreira-Neto

Pedrino

et al. 2012

Purinergic Signalling

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In the nucleus tractus solitarii (NTS) of rats, blockade of extracellular ATP breakdown to adenosine reduces arterial blood pressure (AP) increases that follow stimulation of the hypothalamic defense area (HDA). The effects of ATP on NTS P2 receptors, during stimulation of the HDA, are still unclear. The aim of this study was to determine whether activation of P2 receptors in the NTS mediates cardiovascular responses to HDA stimulation. Further investigation was taken to establish if changes in hindlimb vascular conductance (HVC) elicited by electrical stimulation of the HDA, or activation of P2 receptors in the NTS, are relayed in the rostral ventrolateral medulla (RVLM); and if those responses depend on glutamate release by ATP acting on presynaptic terminals. In anesthetized and paralyzed rats, electrical stimulation of the HDA increased AP and HVC. Blockade of P2 or glutamate receptors in the NTS, with bilateral microinjections of suramin (10 mM) or kynurenate (50 mM) reduced only the evoked increase in HVC by 75 % or more. Similar results were obtained with the blockade combining both antagonists. Blockade of P2 and glutamate receptors in the RVLM also reduced the increases in HVC to stimulation of the HDA by up to 75 %. Bilateral microinjections of kynurenate in the RVLM abolished changes in AP and HVC to injections of the P2 receptor agonist α,β-methylene ATP (20 mM) into the NTS. The findings suggest that HDA-NTS-RVLM pathways in control of HVC are mediated by activation of P2 and glutamate receptors in the brainstem in alerting-defense reactions.

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Section: Hindlimb Vasodilation In Alerting-defense Responses Is Mediamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Korim

Ferreira-Neto

Pedrino

et al. 2012

Purinergic Signalling

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“…These studies were undertaken on nine of the cats described by Silva-Carvalho et al (1995 In twelve of these neurones HDA stimulation evoked EPSPs and associated action potentials (Fig. 2C, D Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…Chemoreceptor-activated neurones are inhibited by baroreceptor inputs (Mifflin, 1993;Felder & Mifflin, 1994). As mentioned already, the effects of chemoreceptor activation can be facilitated by a conditioning stimulus applied to the HDA (Silva-Carvalho et al 1993), a stimulus that also inhibits the baroreceptor reflex (Mifflin, Spyer & Withington-Wray, 1988;Silva-Carvalho et al 1995). The underlying synaptic mechanisms responsible for this reciprocal control of baroreceptor and chemoreceptor function have not as yet been analysed electrophysiologically.…”

mentioning

confidence: 99%

“…The current experiments have thus sought to identify, with intracellular recordings, the effects of hypothalamic stimulation on a selected population of NTS neurones that are activated by both sinus nerve stimulation and natural stimulation of the arterial chemoreceptors. These effects will then be compared with those that have been established for the hypothalamic control of baroreceptor-sensitive neurones in the NTS Jordan, Miffin & Spyer, 1988;Silva-Carvalho et al 1995).…”

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Hypothalamic modulation of the arterial chemoreceptor reflex in the anaesthetized cat: role of the nucleus tractus solitarii.

Silva-Carvalho

Dawid-Milner

Goldsmith

et al. 1995

The Journal of Physiology

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1. There is evidence in the literature of a mutual facilitatory interaction between the arterial chemoreceptor reflex and the alerting stage of the defence reaction, particularly in relation to the patterning of cardiorespiratory activity. The present study has been designed to test the hypothesis that a portion of this interaction involves synaptic interactions within the nucleus tractus solitarii (NTS

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Glutamate receptor subunits in the nucleus of the tractus solitarius and other regions of the medulla oblongata in the cat

et al. 1998

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The nucleus of the tractus solitarius (NTS) is a primary termination zone for laryngeal, gustatory, cardiovascular, respiratory, gastrointestinal, and other visceral afferents. Although considerable information is available on the neurochemical aspects of the NTS in general, very little is known about glutamate receptors that may underlie many of the different functions mediated by the NTS. In addition, most previous glutamate receptor distribution studies were performed in the rat, whereas the cat, the subject of many physiological experiments involving the NTS, has received little attention. In the present study, the immunohistochemical distribution of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-selective glutamate receptor subunits (GluR1, GluR2/3, GluR4) and the N-methyl-D-aspartate (NMDA) receptor subunit NR1 in the cat caudal brainstem was investigated by using subunit-specific antibodies. In the NTS, statistically significant differences were seen in the distribution of each antibody. Highest labeling was seen for GluR2/3 in most subnuclei, whereas GluR1-immunoreactive neurons were found more frequently than were NR1- or GluR4-immunoreactive neurons. GluR1 immunolabeling was particularly high in the interstitial subnucleus, whereas GluR2/3 immunolabeling was particularly high in the intermediate subnucleus. Qualitatively, labeling for GluR4 was most common in glia. The present results indicate that glutamate receptors show different subunit distributions in the subnuclei of the NTS and in other adjacent structures. This finding suggests that neurons in these structures are designed to respond differently to excitatory input.

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The pattern of excitatory inputs to the nucleus tractus solitarii evoked on stimulation in the hypothalamic defence area in the cat.

Abstract: (Richter & Spyer, 1990), but respiratory responses to stimulation in the hypothalamic additionally a modulation of the efficacy of cardio-defence area (HDA) have proved valuable in identifying respiratory reflexes may be involved (Spyer, 1990).

Cited by 34 publications

References 17 publications

Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Hypothalamic modulation of the arterial chemoreceptor reflex in the anaesthetized cat: role of the nucleus tractus solitarii.

Glutamate receptor subunits in the nucleus of the tractus solitarius and other regions of the medulla oblongata in the cat

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