Role of Endogenous Serotonin in Modulating Genioglossus Muscle Activity in Awake and Sleeping Rats

Sood, Sandeep; Morrison, Janna L.; Liu, Hattie; Horner, Richard L.

doi:10.1164/rccm.200502-258oc

Cited by 106 publications

(141 citation statements)

References 64 publications

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“…The magnitude of the depression in GG EMG activity during sleep (Jelev et al, 2001;Sood et al, 2005;Horner, 2008a;Lu and Kubin, 2009) depends strongly on posture, vestibular inputs, and state-dependent neuromodulators (Megirian et al, 1985;Rossiter and Yates, 1996;Horner et al, 2002;Horner, 2008b). Our results suggest that urethane anesthesia does not interfere with the neuromodulatory processes controlling GG muscular activity, at the level of either the motoneuron or premotoneuron networks that determine muscle activity.…”

Section: State-dependent Respiratory Muscle Modulation During Urethanmentioning

confidence: 71%

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

et al. 2012

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Respiratory activity is most fragile during sleep, in particular during paradoxical [or rapid eye movement (REM)] sleep and sleep state transitions. Rats are commonly used to study respiratory neuromodulation, but rodent sleep is characterized by a highly fragmented sleep pattern, thus making it very challenging to examine different sleep states and potential pharmacological manipulations within them. Sleep-like brain-state alternations occur in rats under urethane anesthesia and may be an effective and efficient model for sleep itself. The present study assessed state-dependent changes in breathing and respiratory muscle modulation under urethane anesthesia to determine their similarity to those occurring during natural sleep. Rats were anesthetized with urethane and respiratory airflow, as well as electromyographic activity in respiratory muscles were recorded in combination with local field potentials in neocortex and hippocampus to determine how breathing pattern and muscle activity are modulated with brain state. Measurements were made in normoxic, hypoxic, and hypercapnic conditions. Results were compared with recordings made from rats during natural sleep. Brain-state alternations under urethane anesthesia were closely correlated with changes in breathing rate and variability and with modulation of respiratory muscle tone. These changes closely mimicked those observed in natural sleep. Of great interest was that, during both REM and REM-like states, genioglossus muscle activity was strongly depressed and abdominal muscle activity showed potent expiratory modulation. We demonstrate that, in urethane-anesthetized rats, respiratory airflow and muscle activity are closely correlated with brain-state transitions and parallel those shown in natural sleep, providing a useful model to systematically study sleep-related changes in respiratory control.

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Section: State-dependent Respiratory Muscle Modulation During Urethanmentioning

confidence: 71%

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

et al. 2012

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“…Mean neck muscle activity, diaphragm amplitude and respiratory rate were also calculated in the same consecutive 5 s time-bins for all the periods of sleep and wakefulness in each rat. One rat was excluded from the analysis of genioglossus muscle activity as no respiratory-related activity was recorded under any circumstances during the experiment, which is highly atypical of the rats in this and other studies from our laboratory (Sood et al, 2005;Chan et al, 2006;Younes et al, 2007;Steenland et al, 2008), and as such was a possible indicator that the electrodes were in a different tongue muscle in that animal. In addition, in the potential event of there being little effect of 8-OH-DPAT on the amplitude of respiratory-related genioglossus, such a minimal effect could not be reliably attributed to a lack of drug effect per se and may simply have been due to the fact that there was little/no signal to suppress.…”

Section: Discussionmentioning

confidence: 99%

5-HT_1AReceptor-Responsive Pedunculopontine Tegmental Neurons Suppress REM Sleep and Respiratory Motor Activity

Grace¹,

Liu²,

Horner³

2012

J. Neurosci.

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“…The rats were then implanted with electroencephalogram (EEG) and neck electromyogram (EMG) electrodes for determination of sleep-wake states and with genioglossus and diaphragm electrodes for respiratory muscle recordings (Morrison et al, 2003;Sood et al, 2005;Chan et al, 2006). Tests for the accurate placement of the genioglossus electrodes and their function throughout the experiments included EMG recordings during surgery and observing tongue movements in response to electrical stimulation of the genioglossal wires at both the beginning and end of the experiments (Morrison et al, 2003;Sood et al, 2005;Chan et al, 2006). Removal of the tongue, by dissection, at the completion of all experiments confirmed the physical location of the electrodes to the genioglossus muscle.…”

Section: Surgical Proceduresmentioning

confidence: 99%

“…Using a stereotaxic frame (model 962; David Kopf Instruments), microdialysis guides (CMA/11; Chromatography Sciences Company) were targeted 3 mm above the HMN during surgery (Morrison et al, 2003;Sood et al, 2005;Chan et al, 2006). The guides were placed 13.89 Ϯ 0.11 mm posterior to bregma, 0.12 Ϯ 0.012 mm lateral to the midline, and 6.99 Ϯ 0.071 mm ventral to bregma.…”

Section: Surgical Proceduresmentioning

confidence: 99%

“…The magnitude of respiratory-related hypoglossal nerve or genioglossus activity in those reduced preparations, however, is large compared with the conscious animal (Roda et al, 2004;Sood et al, 2005). Thus, the magnitude and exclusive role of glutamate as the mediator of respiratory drive transmission at the HMN may be lessened or overridden in the intact freely behaving organism as the mechanisms modulating the respiratory network become more complex.…”

Section: Introductionmentioning

confidence: 99%

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Endogenous Glutamatergic Control of Rhythmically Active Mammalian Respiratory Motoneurons In Vivo

Steenland¹,

Liu²,

Horner³

2008

Journal of Neuroscience

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The transmission of rhythmic drive to respiratory motoneurons in vitro is critically dependent on glutamate acting primarily on non-NMDA receptors. We determined whether both non-NMDA and NMDA receptors contribute to respiratory drive transmission at respiratory motoneurons in the intact organism, both in the state of anesthesia and in the same animals during natural behaviors. Twentyseven rats were implanted with electroencephalogram and neck electrodes to record sleep-wake states and genioglossus and diaphragm electrodes for respiratory muscle recordings. Microdialysis probes were inserted into the hypoglossal motor nucleus (HMN). Under anesthesia, non-NMDA or NMDA receptor antagonism significantly decreased respiratory-related genioglossus activity, indicating a contribution of each receptor to respiratory drive transmission at the HMN. However, despite the presence of respiratory-related genioglossus activity in the same rats across sleep-wake states, neither non-NMDA receptor antagonism at the HMN nor glutamate uptake inhibition had any effect on respiratory-related genioglossus activity. These results showed that, compared with anesthesia, respiratory drive transmission through the non-NMDA receptor is low in the behaving organism. In contrast, glutamate uptake inhibition increased tonic genioglossus activity in wakefulness and non-rapid-eye-movement sleep, indicating a functional endogenous glutamatergic modulation of tonic, but not respiratory, motor tone. Such an effect on tonic drive may contribute to the suppression of both tonic and respiratory-related genioglossus activity in wakefulness and sleep with NMDA receptor antagonism at the HMN. These data do not refute previous identification of a glutamatergic (mostly non-NMDA receptor activating) respiratory drive to hypoglossal motoneurons, but this mechanism is more prominent in anesthetized or in vitro preparations.

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Role of Endogenous Serotonin in Modulating Genioglossus Muscle Activity in Awake and Sleeping Rats

Cited by 106 publications

References 64 publications

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

5-HT_1AReceptor-Responsive Pedunculopontine Tegmental Neurons Suppress REM Sleep and Respiratory Motor Activity

Endogenous Glutamatergic Control of Rhythmically Active Mammalian Respiratory Motoneurons In Vivo

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Role of Endogenous Serotonin in Modulating Genioglossus Muscle Activity in Awake and Sleeping Rats

Cited by 106 publications

References 64 publications

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

5-HT1AReceptor-Responsive Pedunculopontine Tegmental Neurons Suppress REM Sleep and Respiratory Motor Activity

Endogenous Glutamatergic Control of Rhythmically Active Mammalian Respiratory Motoneurons In Vivo

Contact Info

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5-HT_1AReceptor-Responsive Pedunculopontine Tegmental Neurons Suppress REM Sleep and Respiratory Motor Activity