Discharge patterns of laryngeal motoneurones in the cat: an intracellular study

Barillot, J.C.; Grélot, Laurent; Reddad, S.; Bianchi, A.L.

doi:10.1016/0006-8993(90)90314-2

Cited by 50 publications

(34 citation statements)

References 20 publications

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“…When considered together with our previous reports (Shannon et al 1998(Shannon et al , 2000, the data support the hypothesis that neurones which shape laryngeal motoneurone activity during cough are reconfigured elements of the eupnoeic respiratory rhythm/pattern-generating network (Barillot et al 1990;Ezure, 1990). The results are consistent with the concept of 'functional plasticity' (multifunctional nature) of the respiratory network and laryngeal motoneurones (Grélot et al 1995;Shiba et al 1999;Gestreau et al 2000).…”

Section: Discussionsupporting

confidence: 80%

Medullary respiratory neurones and control of laryngeal motoneurones during fictive eupnoea and cough in the cat

Baekey¹,

Morris²,

Gestreau³

et al. 2001

The Journal of Physiology

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The effects of strontium ions, Sr2+, on Ca2+‐dependent feedback mechanisms during excitation‐contraction coupling were examined in voltage‐clamped rat ventricular myocytes in which intracellular [Ca2+] and [Sr2+] were monitored with the fluorescent indicator, indo‐1. Voltage clamp depolarizations and caffeine applications during superfusion in Ca2+‐free, Sr2+‐containing solutions were employed to exchange intracellular Ca2+ with Sr2+. Myocytes were loaded with Sr2+ by applying voltage clamp depolarizations during superfusion in Na+‐free, Sr2+‐containing solutions. Caffeine applications produced large fluorescence transients in Sr2+‐loaded cells. Thus, Sr2+ could be sequestered and released from the sarcoplasmic reticulum. Ca2+ influx, but not Sr2+ influx, via sarcolemmal Ca2+ channels evoked ryanodine‐sensitive fluorescence transients in Sr2+‐loaded cells. These results demonstrated that Ca2+ influx‐induced Sr2+ release (CISR) from the sarcoplasmic reticulum occurred in these experiments, even though Sr2+ influx‐induced Sr2+ release was not observed. The amplitude of the Ca2+ influx‐induced fluorescence transient was 17 ± 1% of the caffeine‐induced transient (n= 5 cells), an indication that fractional utilization of Sr2+ sequestered in the sarcoplasmic reticulum during CISR was low. With increased Sr2+ loading, the amplitude of Ca2+ influx‐ and caffeine‐induced fluorescence transients increased, but fractional utilization of sarcoplasmic reticulum divalent cation stores was independent of the degree of Sr2+ loading. These data suggest that Ca2+ influx directly activated the release of divalent cations from the sarcoplasmic reticulum, but mechanisms promoting positive feedback of Sr2+ release were minimal during CISR. By comparison, in Ca2+‐loaded myocytes, Ca2+ influx‐induced Ca2+ release (CICR) utilized a greater fraction of caffeine‐releasable stores than CISR. Fractional utilization of Ca2+ stores during CICR increased with the degree of Ca2+ loading. Taken together, these results suggest that Ca2+‐dependent feedback mechanisms play a major role in determining the extent of sarcoplasmic reticulum Ca2+ release during cardiac excitation‐contraction coupling under a wide range of conditions.

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Section: Discussionsupporting

confidence: 80%

Medullary respiratory neurones and control of laryngeal motoneurones during fictive eupnoea and cough in the cat

Baekey¹,

Morris²,

Gestreau³

et al. 2001

The Journal of Physiology

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“…Number of laryngeal motoneurons studied during behaviors are indicated. Barillot et al (1990). Antidromic latencies of ELMs and ILMs averaged 4.9 Ϯ 2.1 and 5.1 Ϯ 1.1 msec, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…In the present study, we performed intracellular recordings from laryngeal motoneurons activated antidromically from the RLN, i.e., motoneurons of intralaryngeal muscles other than the cricothyroid. Barillot et al (1990) reported that laryngeal motoneurons consist of inspiratory laryngeal motoneurons (ILMs) that depolarize during inspiration and expiratory laryngeal motoneurons (ELMs) that depolarize during expiration. Because the adductor and abductor muscles are activated during the expiratory and inspiratory phases in eupnea, respectively (Wyke and K irchner, 1976;Bartlett, 1986), EL Ms and IL Ms are thought to correspond to the adductor and abductor motoneurons, respectively.…”

Section: Abstract: Laryngeal Motoneuron; Vocalization; Coughing; Swamentioning

confidence: 99%

Multifunctional Laryngeal Motoneurons: an Intracellular Study in the Cat

Shiba¹,

Satoh

Kobayashi

et al. 1999

J. Neurosci.

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We studied the patterns of membrane potential changes in laryngeal motoneurons (LMs) during vocalization, coughing, swallowing, sneezing, and the aspiration reflex in decerebrate paralyzed cats. LMs, identified by antidromic activation from the recurrent laryngeal nerve, were expiratory (ELMs) or inspiratory (ILMs) cells that depolarized during their respective phases in eupnea. During vocalization, most ELMs depolarized and most ILMs hyperpolarized. Some ILMs depolarized slightly during vocalization. During coughing, ELMs depolarized abruptly at the transition from the inspiratory to the expiratory phase. In one-third of ELMs, this depolarization persisted throughout the abdominal burst. In the remainder ("type A"), it was interrupted by a transient repolarization. ILMs exhibited a membrane potential trajectory opposite to that of type A ELMs during coughing. During swallowing, the membrane potential of ELMs decreased transiently at the onset of the hypoglossal burst and then depolarized strongly during the burst. ILMs hyperpolarized sharply at the onset of the burst and depolarized as hypoglossal activity ceased. During sneezing, ELMs and ILMs exhibited membrane potential changes similar to those of type A ELMs and ILMs during coughing. During the aspiration reflex, ELMs and ILMs exhibited bell-shaped hyperpolarization and depolarization trajectories, respectively. We conclude that central drives to LMs, consisting of complex combinations of excitation and inhibition, vary during vocalization and upper airway defensive reflexes. This study provides data for analysis of the neuronal networks that produce these various behaviors and analysis of network reorganization caused by changes in dynamic connections between the respiratory and nonrespiratory neuronal networks.

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“…Laryngeal motoneurons activated antidromically from the recurrent laryngeal nerve were classified as expiratory laryngeal motoneurons (ELMs) or inspiratory laryngeal motoneurons according to their expiratory or inspiratory depolarization, respectively (Barillot et al, 1990;Shiba et al, 1999). ELMs are considered to correspond to adductor motoneurons.…”

Section: Methodsmentioning

confidence: 99%

“…Once an EAUG neuron projecting to the motoneuron pool was identified, an ELM was impaled using a glass electrode containing 3 M KCl (tip impedance, 8 -25 M⍀). ELMs were identified by antidromic activation from the recurrent laryngeal nerve and by expiratory-related depolarization (Barillot et al, 1990;Shiba et al, 1999). For each ELM, the membrane potential was defined as the difference between the intracellular and extracellular potentials, using a single grounded Ag/AgCl electrode inserted into the temporalis muscle as a reference.…”

Section: Methodsmentioning

confidence: 99%

Multifunctional Laryngeal Premotor Neurons: Their Activities during Breathing, Coughing, Sneezing, and Swallowing

Shiba¹,

Nakazawa²,

Ono³

et al. 2007

J. Neurosci.

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To examine whether motor commands of two or more distinct laryngeal motor patterns converge onto a common premotor network, we conducted dual recordings from the laryngeal adductor motoneuron and its premotor neuron within the brainstem respiratory circuitry during fictive breathing, coughing, sneezing, and swallowing in decerebrate paralyzed cats. Expiratory neurons with an augmenting firing pattern (EAUG), whose action potentials evoked monosynaptic IPSPs in the adductor motoneurons, sharply fired during the expulsive phases of fictive coughing and sneezing, during which the adductor motoneurons transiently repolarized. In contrast, these premotor neurons were silent during the swallow-related hyperpolarization in adductor motoneurons. These results show that one class of medullary respiratory neuron, EAUG, is multifunctional and shared among the central pattern generators (CPGs) for breathing, coughing, and sneezing. In addition, although the CPGs underlying these three behaviors and the swallowing CPG do overlap, EAUG neurons are not part of the swallowing CPG and, in contrast to the other three behaviors, are not a source of inhibitory input to adductor motoneurons during swallowing.

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Discharge patterns of laryngeal motoneurones in the cat: an intracellular study

Cited by 50 publications

References 20 publications

Medullary respiratory neurones and control of laryngeal motoneurones during fictive eupnoea and cough in the cat

Medullary respiratory neurones and control of laryngeal motoneurones during fictive eupnoea and cough in the cat

Multifunctional Laryngeal Motoneurons: an Intracellular Study in the Cat

Multifunctional Laryngeal Premotor Neurons: Their Activities during Breathing, Coughing, Sneezing, and Swallowing

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