Laryngeal respiratory motoneurones: Morphology and electrophysiological evidence of separate sites for excitatory and inhibitory synaptic inputs

Barillot, J.C.; Bianchi, A.L.; Gogan, P.

doi:10.1016/0304-3940(84)90414-2

Cited by 35 publications

(23 citation statements)

References 9 publications

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“…Some neurones discharged only briefly in early expiration, whilst others continued to discharge into the late expiratory phase. These control patterns are consistent with other reports (Barillot & Dussardier, 1976;Barillot et al 1984Barillot et al , 1990Iscoe, 1988;Gestreau et al 2000). Three 'silent' cells identified as motoneurones were recruited during fictive cough; these neurones also exhibited a decrementing expiratory discharge pattern.…”

Section: Expiratory Laryngeal Motoneuronessupporting

confidence: 81%

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: Expiratory Laryngeal Motoneuronessupporting

confidence: 81%

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 caudal VRG is mainly composed of expiratory neurons but also contains some inspiratory and phase-spanning neurons (Miller et al 1985). In addition, dendrites of VRG neurons are known to project a substantial distance from the cell bodies (Barillot et al 1984;Arita et al 1987;Sasaki et al 1989) resulting in an overlap of dendritic trees belonging to various anatomical and functional groups.…”

Section: Discussionmentioning

confidence: 99%

Extensive monosynaptic inhibition of ventral respiratory group neurons by augmenting neurons in the Bötzinger complex in the cat

1990

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Axonal projections and synaptic connectivity of expiratory Bötzinger neurons with an augmenting firing pattern (Bot-Aug neurons) to neurons in the ipsilateral ventral respiratory group (VRG) were studied in anaesthetized cats. Antidromic mapping revealed extensive axonal arborizations of Bot-Aug neurons (24 of 45) to the rostral or caudal VRG, with some having arbors in both regions. Of 234 pairs of neurons studied with intracellular recording and spike-triggered averaging, monosynaptic inhibitory postsynaptic potentials (IPSPs) were evoked in 49/221 VRG neurons by 38/98 Bot-Aug neurons. The highest incidence of monosynaptic inhibition was found in inspiratory bulbospinal neurons (10 of 23 tested). Evidence was also found for monosynaptic inhibition, by a separate group of Bot-Aug neurons, of expiratory bulbospinal neurons (12/58), while excitatory postsynaptic potentials (EPSPs) were identified in another two of these neurons. In addition, monosynaptic IPSPs were recorded from 13 of 53 identified laryngeal motoneurons, and from 14 of 100 respiratory propriobulbar neurons. Presumptive disynaptic IPSPs were recorded from 11 of the 221 VRG neurons. We conclude that Bot-Aug neurons exert widespread inhibition on all major neuron categories in the ipsilateral VRG, and should be regarded as an important element in shaping the spatiotemporal output pattern of both respiratory motoneurons and premotor neurons.

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“…These midbrain areas can function independently from higher order structures, and lesions at this level drastically change the structure of species-specific vocalizations (Movchan, 1984;Kirzinger and Jurgens, 1985). The fourth organizational level consists of a diffuse system within the lateral pontine and medullary reticular formation in the vicinity of specific motoneurons Martin, 1979, 1983;Schweizer et al, 1981;Muller-Preuss and Ploog, 1983;Travers and Norgren, 1983;Yajima and Hayashi, 1983;Barrilot et al, 1984;Rubsamen and Betz, 1986;Rubsamen and Schweizer, 1986;Vartanyan and Chernigovskaya, 1990;Dressnandt and Jurgens, 1992;Yajima and Larson, 1993). The motor nucleus of laryngeal control, the nucleus ambiguus, gives rise to the tenth cranial nerve innervating the larynx.…”

Section: Compensation Sensory-motor Interface Vocalizationmentioning

confidence: 97%

Anatomical basis for audio-vocal integration in echolocating horseshoe bats

Metzner

1996

J. Comp. Neurol.

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Neurophysiological recordings suggest that audio-vocal neurons located in the paralemniscal tegmentum of the midbrain in horseshoe bats provide an interface between the pathways for auditory sensory processing and those for the motor control of vocalization. To verify these physiological results anatomically, the projection pattern of the audio-vocally active area in the paralemniscal tegmentum was investigated by using extracellular tracer injections of wheat germ agglutinin conjugated to horseradish peroxidase. Several nuclei of the lemniscal auditory pathway (dorsal nucleus of the lateral lemniscus, central nucleus of the inferior colliculus, lateral superior olive) as well as the nucleus of the central acoustic tract appear to project to the paralemniscal tegmentum. Other possible sources of afferent projections are a small but distinctly labeled structure within the lateral hypothalamic area, the substantia nigra pars compacta, the deep mesencephalic nucleus, the rostral portion of the inferior colliculus, the deep and intermediate layers of the superior colliculus, and several small areas in the rhombencephalic reticular formation. No direct efferent projection from the audio-vocally active area of the paralemniscal tegmentum to primarily auditory structures was found. Instead, the main targets were structures that are involved in the control of different motor patterns. These targets include the deep and intermediate layers of the superior colliculus and the dorsomedial portion of the facial nucleus, both of which most probably control pinna movements in cats, and the reticular formation medial and caudal to the facial nucleus and rostral to the nucleus ambiguus, which represents an area involved in the control of vocalization. Hence, the anatomical projection pattern suggests that the paralemniscal tegmentum in horseshoe bats serves as a link between the processing of auditory information and the control of vocalization and related motor patterns.

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Laryngeal respiratory motoneurones: Morphology and electrophysiological evidence of separate sites for excitatory and inhibitory synaptic inputs

Cited by 35 publications

References 9 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

Extensive monosynaptic inhibition of ventral respiratory group neurons by augmenting neurons in the Bötzinger complex in the cat

Anatomical basis for audio-vocal integration in echolocating horseshoe bats

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