Excitatory amino acid neurotransmission in superior laryngeal nerve-evoked inspiratory termination

1993 ◽  
Vol 74 (4) ◽  
pp. 1840-1847 ◽  
Author(s):  
D. R. Karius ◽  
L. Ling ◽  
D. F. Speck
Keyword(s):  
Amino Acid ◽  
Nucleus Tractus Solitarius ◽  
Excitatory Amino Acid ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Neural Pathways ◽  
Medial Nucleus ◽  
Inspiratory Motor ◽  
Adult Cats ◽  
Stimulation Of

Superior laryngeal nerve (SLN) stimulation elicits a transient inhibition of inspiration (single shocks) or inspiratory termination (stimulus trains). The neural pathways mediating these responses are unknown, but the medial nucleus tractus solitarius (mNTS) has been implicated in the termination reflex. This study tested the hypothesis that SLN-evoked inspiratory termination requires excitatory amino acid (EAA) neurotransmission in medial aspects of the NTS. Experiments were conducted in decerebrate, vagotomized, and paralyzed adult cats. Inspiratory motor output was recorded from the phrenic nerve. After control responses to SLN stimulation were recorded, a unilateral injection of the EAA antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX, 10 mM) was made into the mNTS. The transient inhibitions were not altered by DNQX. Inspiratory termination elicited by stimulation of the SLN contralateral to the injection persisted after DNQX (n = 4). Stimulation of the ipsilateral SLN no longer elicited termination (5 of 9 animals) or did so only at greatly elevated thresholds (4 of 9). We conclude that EAA neurotransmission in the mNTS is not required in the transient reflex but is necessary for the production of the SLN-evoked inspiratory termination.

Nucleus tractus solitarius and excitatory amino acids in afferent-evoked inspiratory termination

1994 ◽  
Vol 76 (3) ◽  
pp. 1293-1301 ◽  
Author(s):  
D. R. Karius ◽  
L. Ling ◽  
D. F. Speck
Keyword(s):  
Nmda Receptors ◽  
Nucleus Tractus Solitarius ◽  
Excitatory Amino Acid ◽  
Superior Laryngeal Nerve ◽  
Nmda Antagonist ◽  
Intercostal Nerve ◽  
Laryngeal Nerve ◽  
Receptor Antagonists ◽  
Adult Cats ◽  
Stimulation Of

This study tested the hypothesis that excitatory amino acid (EAA) neurotransmission at non-N-methyl-D-aspartate (non-NMDA), but not NMDA, receptors within medial regions of the nucleus tractus solitarius (NTS) is required in the inspiratory termination elicited by vagal or intercostal nerve (ICN) stimulation. Adult cats were anesthetized, decerebrated, vagotomized, and ventilated. After control responses to stimulation of the superior laryngeal nerve (SLN), vagus, and ICN were obtained, EAA receptor antagonists were injected into the medial aspects of the NTS. Injections of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or 6,7-dinitro-quinoxaline-2,3-dione (DNQX), EAA receptor antagonists; (+/-)-2-amino-5-phosphonopentanoic acid (AP5), an NMDA antagonist; or 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX), a non-NMDA antagonist, ipsilateral to the vagus abolished the termination response. The SLN-elicited response persisted after AP5 injection but was abolished by NBQX injections. The ICN-elicited response persisted after bilateral injections of CNQX/DNQX or procaine. We conclude that the inspiratory termination elicited by ICN stimulation is independent of the regions medial to the NTS. Inspiratory termination elicited by vagal or SLN stimulation requires non-NMDA-mediated EAA neurotransmission within medial aspects of the NTS, but the vagally elicited response also requires NMDA receptors.

Excitatory amino acid receptors of guinea pig medial nucleus tractus solitarius neurons

1990 ◽  
Vol 259 (5) ◽  
pp. H1389-H1395 ◽  
Author(s):  
J. A. Drewe ◽  
R. Miles ◽  
D. L. Kunze
Keyword(s):  
Amino Acid ◽  
Glutamate Receptor ◽  
Nucleus Tractus Solitarius ◽  
Excitatory Amino Acid ◽  
Membrane Conductance ◽  
Diethyl Ester ◽  
Receptor Subtypes ◽  
Amino Acid Receptors ◽  
Medial Nucleus ◽  
Inward Currents

Neurons isolated from the medial subnuclei of nucleus tractus solitarius in adult guinea pigs were studied for responses to the excitatory amino acid glutamate and its analogues using the whole cell tight-seal voltage clamp technique. In 80% of the cells studied (n = 60) 100 microM glutamate produced inward currents at negative voltages. To further characterize the glutamate response, the agonists for three glutamate receptor subtypes, N-methyl-D-aspartate (NMDA), kainate, and quisqualate, were examined for their effects on membrane conductance. NMDA (25-250 microM) activated currents in 85% of the neurons tested (n = 30). NMDA currents were generally very small in amplitude. Of the neurons tested, 84% responded to kainate (10-30 microM, n = 19) and only 50% to quisqualate (25-50 microM, n = 26). The conductance activated by NMDA was outwardly rectifying. The conductance activated by kainate was voltage independent, while that activated by quisqualate showed varying degrees of outward rectification. Responses to NMDA were specifically antagonized by DL-2-amino-5-phosphonovaleric acid (AP-5, 50-100 microM). Kainate responses were blocked by kynurenate at concentrations (0.5-1.5 mM) ineffective on quisqualate-induced current. Glutamic acid diethyl ester (GDEE, 2-15 mM) was effective in reducing quisqualate responses at concentrations that had no effect on kainate responses. This characterization of the glutamate receptor subtypes and effective antagonists provides a basis for future determination of the specific receptor of glutamate responsible for mediation of the excitatory postsynaptic potentials produced by activation of the baroreceptor input.

Cross-Innervation of the Thyroarytenoid Muscle by a Branch from the External Division of the Superior Laryngeal Nerve

1997 ◽  
Vol 106 (7) ◽  
pp. 594-598 ◽  
Author(s):  
Sina Nasri ◽  
Joel A. Sercarz ◽  
Pouneh Beizai ◽  
Young-Mo Kim ◽  
Ming Ye ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Spasmodic Dysphonia ◽  
Clinical Implications ◽  
Motor Innervation ◽  
Vocal Fold Vibration ◽  
Adductor Spasmodic Dysphonia ◽  
Thyroarytenoid Muscle ◽  
Stimulation Of

The neuroanatomy of the larynx was explored in seven dogs to assess whether there is motor innervation to the thyroarytenoid (TA) muscle from the external division of the superior laryngeal nerve (ExSLN). In 3 animals, such innervation was identified. Electrical stimulation of microelectrodes applied to the ExSLN resulted in contraction of the TA muscle, indicating that this nerve is motor in function. This was confirmed by electromyographic recordings from the TA muscle. Videolaryngostroboscopy revealed improvement in vocal fold vibration following stimulation of the ExSLN compared to without it. Previously, the TA muscle was thought to be innervated solely by the recurrent laryngeal nerve. This additional pathway from the ExSLN to the TA muscle may have important clinical implications in the treatment of neurologic laryngeal disorders such as adductor spasmodic dysphonia.

Excitatory amino acid receptors in commissural nucleus of the NTS mediate carotid chemoreceptor responses

1993 ◽  
Vol 264 (1) ◽  
pp. R41-R50 ◽  
Author(s):  
A. Vardhan ◽  
A. Kachroo ◽  
H. N. Sapru
Keyword(s):  
Amino Acid ◽  
Carotid Body ◽  
Excitatory Amino Acid ◽  
Minute Ventilation ◽  
Neuronal Cell ◽  
Excitatory Amino Acid Receptors ◽  
Amino Acid Receptors ◽  
Neuronal Cell Bodies ◽  
Carotid Body Chemoreceptors ◽  
Stimulation Of

Stimulation of carotid body chemoreceptors by saline saturated with 100% CO2 elicited an increase in mean arterial pressure, respiratory rate, tidal volume, and minute ventilation (VE). Microinjections of L-glutamate into a midline area 0.5-0.75 mm caudal and 0.3-0.5 mm deep with respect to the calamus scriptorius increased VE. Histological examination showed that the site was located in the commissural nucleus of the nucleus tractus solitarii (NTS). The presence of excitatory amino acid receptors [N-methyl-D-aspartic acid (NMDA); kainate, quisqualate/alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and trans 1-amino-cyclopentane-trans-1,3-dicarboxylic acid (ACPD)] in this area was demonstrated by microinjections of appropriate agonists. Simultaneous blockade of NMDA and non-NMDA receptors by combined injections of DL-2-aminophosphonoheptanoate (AP-7; 1 nmol) and 6,7-dinitro-quinoxaline-2,3-dione (DNQX; 1 nmol) abolished the responses to stimulation of carotid body on either side. Combined injections of AP-7 and DNQX did not produce a nonspecific depression of neurons because the responses to another agonist, carbachol, remained unaltered. Inhibition of the neurons in the aforementioned area with microinjections of muscimol (which hyperpolarizes neuronal cell bodies but not fibers of passage) also abolished the responses to subsequent carotid body stimulation on either side.(ABSTRACT TRUNCATED AT 250 WORDS)

Excitatory amino acid receptors within NTS mediate arterial chemoreceptor reflexes in rats

1993 ◽  
Vol 265 (2) ◽  
pp. H770-H773 ◽  
Author(s):  
W. Zhang ◽  
S. W. Mifflin
Keyword(s):  
Electrical Stimulation ◽  
Amino Acid ◽  
Receptor Antagonist ◽  
Carotid Body ◽  
Excitatory Amino Acid ◽  
Pressor Responses ◽  
Carotid Body Chemoreceptors ◽  
Arterial Chemoreceptor ◽  
Stimulation Of ◽  
Arterial Baroreceptor

The nucleus tractus solitarius (NTS) is the primary site of termination of arterial baroreceptor and chemoreceptor afferent fibers. Excitatory amino acid (EAA) receptors within NTS have been shown to play an important role in the mediation of arterial baroreceptor reflexes; however, the importance of EAA receptors within NTS in the mediation of arterial chemoreceptor reflexes remains controversial. Therefore, in chloralose-urethan-anesthetized, mechanically ventilated, paralyzed rats, 4 nmol of the broad-spectrum EAA receptor antagonist kynurenic acid (Kyn) was injected into the NTS to observe the effects of EAA receptor blockade on the pressor responses evoked by either activation of ipsilateral carotid body chemoreceptors (by close arterial injection of CO2-saturated bicarbonate) or electrical stimulation of ipsilateral carotid sinus nerve (CSN). Under control conditions, activation of carotid body chemoreceptors and CSN stimulation evoked increases in arterial pressure of 27 +/- 2 (n = 24 sites) and 28 +/- 3% (n = 8), respectively. Kyn microinjection into NTS significantly reduced the pressor responses evoked by activation of carotid body chemoreceptors and electrical stimulation of the CSN for 20 and 25 min, respectively. Attenuation of pressor responses evoked by chemoreceptor activation were maximal at 20 min post-Kyn injection (13 +/- 2%), whereas CSN-evoked pressor responses were maximally attenuated at 15 min (6 +/- 4%). Microinjection into NTS of 4 nmol of xanthurenic acid, a structural analogue of Kyn with no EAA receptor antagonist properties, had no effect on chemoreceptor reflexes. We conclude that EAA receptors within NTS play an important role in the mediation of arterial chemoreceptor reflexes.

Influences of superior laryngeal afferent stimulation on expiratory activity in cats

1988 ◽  
Vol 65 (1) ◽  
pp. 385-392 ◽  
Author(s):  
F. Bongianni ◽  
M. Corda ◽  
G. Fontana ◽  
T. Pantaleo
Keyword(s):  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Tetanic Stimulation ◽  
Bötzinger Complex ◽  
Dependent Activity ◽  
Inspiratory Activity ◽  
Polysynaptic Reflex ◽  
Expiratory Muscles ◽  
Excitatory Responses ◽  
Stimulation Of

The effects of superior laryngeal nerve (SLN) stimulation on the activity of the expiratory muscles and medullary expiration-related (ER) neurons were investigated in 24 pentobarbital-anesthetized cats. In some experiments the animals were also paralyzed and artificially ventilated. Sustained tetanic stimulation of SLN consistently caused an apneic response associated with the appearance of tonic CO2-dependent activity in the expiratory muscles and in ER neurons located in the caudal ventral respiratory group (VRG) and the Botzinger complex. Single shocks or brief tetani at the same stimulation intensities failed to evoke excitatory responses in the expiratory muscles and in the vast majority of ER neurons tested. At higher stimulation strengths, single shocks or short tetani elicited excitatory responses in the expiratory muscles (20- to 35-ms latency) and in the majority of ER neurons of the caudal VRG (7.5- to 15.5-ms latency). These responses were obtained only during the expiratory phase and proved to be CO2 independent. On the contrary, only inhibitory responses were evoked in the activity of Botzinger complex neurons. The observed tonic expiratory activity most likely represents a disinhibition phenomenon due to the suppression of inspiratory activity; activation of expiratory muscles at higher stimulation intensities appears to be a polysynaptic reflex mediated by ER neurons of the caudal VRG but not by Botzinger complex neurons.

scholarly journals Chronic Electrical Stimulation of the Superior Laryngeal Nerve in the Rat: A Potential Therapeutic Approach for Postmenopausal Osteoporosis

Biomedicines ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 369
Author(s):  
Kaori Iimura ◽  
Nobuhiro Watanabe ◽  
Philip Milliken ◽  
Yee-Hsee Hsieh ◽  
Stephen J. Lewis ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Thyroid Gland ◽  
Venous Blood ◽  
Disease Model ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Mineral Density ◽  
Ovx Rats ◽  
Chronic Electrical Stimulation ◽  
Stimulation Of

Electrical stimulation of myelinated afferent fibers of the superior laryngeal nerve (SLN) facilitates calcitonin secretion from the thyroid gland in anesthetized rats. In this study, we aimed to quantify the electrical SLN stimulation-induced systemic calcitonin release in conscious rats and to then clarify effects of chronic SLN stimulation on bone mineral density (BMD) in a rat ovariectomized disease model of osteoporosis. Cuff electrodes were implanted bilaterally on SLNs and after two weeks recovery were stimulated (0.5 ms, 90 microampere) repetitively at 40 Hz for 8 min. Immunoreactive calcitonin release was initially measured and quantified in systemic venous blood plasma samples from conscious healthy rats. For chronic SLN stimulation, stimuli were applied intermittently for 3–4 weeks, starting at five weeks after ovariectomy (OVX). After the end of the stimulation period, BMD of the femur and tibia was measured. SLN stimulation increased plasma immunoreactive calcitonin concentration by 13.3 ± 17.3 pg/mL (mean ± SD). BMD in proximal metaphysis of tibia (p = 0.0324) and in distal metaphysis of femur (p = 0.0510) in chronically SLN-stimulated rats was 4–5% higher than that in sham rats. Our findings demonstrate chronic electrical stimulation of the SLNs produced enhanced calcitonin release from the thyroid gland and partially improved bone loss in OVX rats.

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