Metabotropic glutamate receptors are involved in the control of breathing at the medulla oblongata level of anaesthetized rats

Vitagliano, S.; Berrino, Liberato; Pizzirusso, Anna; D’Amico, Michele; Calderaro, V.; Maione, Sabatino; Rossi, Francesco

doi:10.1016/0028-3908(94)90182-1

Cited by 18 publications

(11 citation statements)

References 24 publications

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“…Pulmonary afferents from slowly adapting lung stretch afferents synapse on inspiratory NTS neurons in the rostral NTSint and NTSvl subnuclei while the afferents from the rapidly adapting lung receptor afferents predominantly innervate the more caudal NTS-int and NTScomm subnuclei (Averill et al, 1984;Backman et al, 1984 ;Berger and Dick, 1987;Davies and Kubin, 1986). This is consistent with reports suggesting that activation of mGluRs with microinjections of t-ACPD into the respiratory regions of the NTS results in apnea and hypotension (Vitagliano, 1994;Li and Nattie,1995). However, there was no evidence for mGluR expression in the ventrolateral regions of the NTS.…”

Section: Nucleus Of the Solitary Tractsupporting

confidence: 92%

“…Microinjection of mGluR agonists and antagonists into the medial NTS have been shown to modulate sympathetic nerve activity (Foley et al, 1998) and in vitro studies have established that mGluR(s) are important in both pre-and postsynaptic neurotransmission at the level of the NTS (Glaum and Miller, 1992;Glaum et al, 1993;Glaum and Miller, 1994). Glutamate has also been suggested to be involved in the neurotransmission in the ventral lateral medulla (Smith and Barron, 1990;Chalmers and Pilowski, 1991;Miura et al,1991), and studies in anesthetized rats have shown that mGluR activation may be involved in the regulation of cardiovascular and respiratory function within this region (Tsuchiahashi et al, 1994;Vitagliano et al,1994;Li and Nattie, 1995).…”

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confidence: 99%

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Heterogeneity of metabotropic glutamate receptors in autonomic cell groups of the medulla oblongata of the rat

et al. 1999

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Metabotropic glutamate receptors (mGluRs) in the medulla oblongata have been suggested to be involved in the regulation of autonomic function. The aim of the present study was to examine the localization and expression of four types of mGluRs: mGluR1a, mGluR2/3, mGluR5, and mGluR7 in the dorsal and ventral autonomic nuclei of the medulla of the rat. The four mGluR subtypes studied were differentially distributed in distinct subnuclei in the nucleus of the solitary tract (NTS). mGluR1a immunoreactivity was identified in cell bodies, dendrites, and axonal processes in the intermediate, dorsal lateral, and interstitial subnuclei of the NTS. No mGluR1a immunoreactivity was observed in the commissural or medial NTS subnuclei. Immunoreactivity for mGluR2/3 and mGluR5 as observed in fibers and putative axonal processes in the interstitial, intermediate, and dorsolateral subnuclei of the NTS. In contrast, mGluR7 was expressed primarily in fibers and terminals in the central and commissural NTS subnuclei. Expression of mGluR2/3 was clearly evident in cell bodies, dendrites, and axonal processes within the area postrema. The vagal outflow nuclei were also studied. The dorsal motor nucleus of the vagus (DMN) contained mGluR1a cell bodies, dendrites, and axonal fibers and light mGluR2/3 processes. Throughout the rostral‐caudal extent of the compact and semicompact formation nucleus ambiguus, mGluR1a was found in cell bodies and fibers. Within the caudal and rostral regions of the ventral lateral medulla, mGluR1a was observed in cell bodies and fibers. Cell bodies containing mGluR1a were found adjacent to cells staining positive for tyrosine hydroxylase (TH) in these regions but were not colocalized with the TH staining. However, mGluR1a‐expressing neurons in the ventral lateral medulla did appear to receive innervation from TH‐containing fibers. These results suggest that the mGluR1a‐expressing neurons within the ventral lateral medulla are predominantly not catecholaminergic but may be innervated by catecholamine‐containing fibers. These data are the first to provide a mapping of the different mGluR subtypes within the medulla and may facilitate predictions regarding the function of L‐glutamate neurotransmission in these regions. J. Comp. Neurol. 403:486–501, 1999. © 1999 Wiley‐Liss, Inc.

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Section: Nucleus Of the Solitary Tractsupporting

confidence: 92%

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confidence: 99%

Heterogeneity of metabotropic glutamate receptors in autonomic cell groups of the medulla oblongata of the rat

et al. 1999

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“…The most abundant and well-studied presynaptic glutamate receptors are metabotropic types (Petralia et al, 1996a,b;Shigemoto et al, 1996). Metabotropic glutamate receptors were not examined in the present study, although they are prevalent in the NTS and include both postsynaptic and presynaptic locations Miller, 1994, 1995;Vitagliano et al, 1994;Hay and Lindsley, 1995;Jones et al, 1998). Presynaptic metabotropic glutamate receptors in the NTS modulate the activity of synapses by facilitating (Jones et al, 1998) or inhibiting (Glaum and Miller, 1995) the release of neurotransmitters.…”

Section: Distribution In the Nucleus Of The Tractus Solitariusmentioning

confidence: 92%

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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“…Electrophysiological observations ex vivo in slices of NTS also support roles for pre‐ and postsynaptically located mGluRs, some of which appear to be associated with vagal afferents (Glaum & Miller 1992; 1993; Glaum et al ., 1993). mGluRs are additionally likely to have cardiorespiratory (Vitagliano et al ., 1994) and chemoreceptor (Vardhan et al ., 1993a,1993b) roles in the NTS suggesting a wider involvement in central autonomic mechanisms. Other evidence suggests roles for mGluRs of CVLM and RVLM (Tsuchihashi & Averill, 1993; Tsuchihashi et al ., 1994; 1997) in the sympathetic baroreflex circuitry, and possibly in respiratory regulation (Vitagliano et al ., 1994; Li & Nattie, 1995).…”

Section: Introductionmentioning

confidence: 99%

Type I and II metabotropic glutamate receptor agonists and antagonists evoke cardiovascular effects after intrathecal administration in conscious rats

Beart

Monn

et al. 1999

British J Pharmacology

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1 In the present study, the role of metabotropic glutamate receptors (mGluRs) in central cardiovascular regulation in conscious rats was examined. To this end, agonists and antagonists for type I and II mGluRs were administered intrathecally, and the temporal changes in blood pressure and heart rate were recorded. 2 L-glutamate (1 mmol) and the prototypical mGluR agonist (1S,3R)-ACPD (0.1 and 0.3 mmol) both increased mean arterial pressure (MAP) and heart rate (HR), implicating functional mGluRs in the spinal cord. The type I mGluR agonist DHPG (0.01 ± 0.1 mmol) evoked increases in MAP (max=25+5 mmHg) and HR (max=88+23 beats min 71 ). The duration of action, but not the maximum e ects, were dose-related and ranged from approximately 10 min to 590 min and 1 min to 490 min for MAP and HR, respectively. 3 The type I/II mGluR agonist CCG-1 (0.1 and 0.3 mmol) caused smaller, variable increases in MAP and HR of intermediate duration (5 ± 20 min), whereas the type II MGluR agonist APDC (0.1 and 1.0 mmol) caused marked, but transient (3 ± 5 min), pressor and tachycardic responses. The highest doses of DHPG and CCG-1, but not APDC, also evoked behavioural responses similar to a spontaneous nociceptive behavioural e ect reported previously. 4 The type I and II mGluR antagonists (AIDA and LY307452, respectively) were also given approximately 5 min before the administration of the respective type I and II mGluR agonists (DHPG and APDC). Both compounds caused pressor and tachycardic responses, with the e ect of AIDA, but not LY307452, returning to control levels before mGluR agonist administration. AIDA signi®cantly attenuated the overall cardiovascular e ects of DHPG, while LY307452 signi®cantly attenuated the overall cardiovascular e ects of APDC. 5 These results indicate that functional type I and II mGluRs exist in the spinal cord, and that their activation evokes prolonged cardiovascular e ects.

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Metabotropic glutamate receptors are involved in the control of breathing at the medulla oblongata level of anaesthetized rats

Cited by 18 publications

References 24 publications

Heterogeneity of metabotropic glutamate receptors in autonomic cell groups of the medulla oblongata of the rat

Heterogeneity of metabotropic glutamate receptors in autonomic cell groups of the medulla oblongata of the rat

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

Type I and II metabotropic glutamate receptor agonists and antagonists evoke cardiovascular effects after intrathecal administration in conscious rats

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