Spontaneous crossed phrenic activity in the neonatal respiratory network

Zimmer, M. Beth; Goshgarian, Harry G.

doi:10.1016/j.expneurol.2005.03.013

Cited by 19 publications

(28 citation statements)

References 41 publications

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“…Nonetheless, the relative strength of coherence in both preparations implies that these motor neuron pools are driven by common sources and/or are locally coupled. Functional coupling between the left and right Ph output has been noted in neonates (30), and our results suggest that it is quite robust in juveniles. Furthermore, HFO tend to have more consistently high coherence than the MFO in adult rats (15).…”

Section: ͔mentioning

confidence: 64%

“…For example, Zimmer and Goshgarian (30), working in neonatal rats (P0-P4) rats in vitro, found that younger preparations demonstrated higher degrees of C 4 /C 5 ventral root phasic activity ipsilateral to C 2 hemisection than preparations made from older neonates, suggesting a higher degree of shared descending input or local functional coupling caudal to C 2 in younger animals. A commonly used measure of phase constancy in coupled oscillations is coherence, which may be caused by common inputs, direct coupling, or both.…”

mentioning

confidence: 97%

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Temperature and state dependence of dynamic phrenic oscillations in the decerebrate juvenile rat

Marchenko

Rogers²

2007

American Journal of Physiology-Regulatory, Integrative and Comp

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The aim of the present study was to determine characteristics of fast oscillations in the juvenile rat phrenic nerve (Ph) and to establish their temperature and state dependence. Two different age-matched decerebrate, baro- and chemodenervated rat preparations, in vivo and in situ arterially perfused models, were used to examine three systemic properties: 1) generation and dynamics of fast oscillations in Ph activity (both preparations), 2) responses to anoxia (both preparations), and 3) the effects of temperature on fast oscillations (in situ only). Both juvenile preparations generated power and coherence in two major bands analogous to adult medium- and high-frequency oscillations (HFO) at frequencies that increased with temperature but were lower than in adults. At < 28 degrees C, however, Ph oscillations were confined primarily to one low-frequency band (20-45 Hz). During sustained anoxia, both preparations produced stereotypical state changes from eupnea to hyperpnea to transition bursting (a behavior present only in vivo during incomplete ischemia) to gasping. Thus the juvenile rat produces a sequential pattern of responses to anoxia that are intermediate forms between those produced by neonates and those produced by adults. Time-frequency analysis determined that fast oscillations demonstrated dynamics over the course of the inspiratory burst and a state dependence similar to that of adults in vivo in which hyperpnea (and transition) bursts are associated with increases in HFO, while gasping contains no HFO. Our results confirm that both the fast oscillations in Ph activity and the coherence between Ph pairs produced by the juvenile rat are profoundly state- and temperature-dependent.

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Section: ͔mentioning

confidence: 64%

mentioning

confidence: 97%

Temperature and state dependence of dynamic phrenic oscillations in the decerebrate juvenile rat

Marchenko

Rogers²

2007

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Subsequent transection of the phrenic nerve contralateral to the hemisection induces asphyxia, which enhances central respiratory drive and, thus, activates the latent respiratory motor pathway, reestablishing function to the hemidiaphragm paralyzed by hemisection [267]. Activation of the latent respiratory motor pathway can also be achieved pharmacologically by the application of antagonist of adenosine receptor type 1 and agonists of adenosine receptor type 2 [268,269] as well as serotonergic agonists [270,271] by a mechanism mediated by the 5-HT2 receptor [272]. These experimental data open a therapeutic window to be considered in the treatment of this particular consequence of spinal cord injury.…”

Section: Spinal Cord Injurymentioning

confidence: 98%

Breathing Generation and Potential Pharmacotherapeutic Approaches to Central Respiratory Disorders

Peña

García²

2006

CMC

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Breathing is generated and controlled by a brainstem neuronal network. Both intrinsic and synaptic interactions are involved in respiratory rhythm generation and their contribution is state-dependent, changing with hypoxia and the neuromodulatory state. Cellular mechanisms involved in acute or chronic pathological conditions are still unknown. A dysfunction in the neuronal network that controls breathing may be involved in several respiratory disorders such as central sleep apnea, sudden infant death syndrome, congenital hypoventilation, and in some clinical conditions that produce breathing dysfunction such as drug-induced respiratory depression, obesity hypoventilation syndrome, etc. Despite the fact that several drugs are currently used to treat these diseases, the probable effects of this pharmacotherapy on the central rhythm generator and on other neuronal networks related with breathing control is poorly understood. Here, we review the current pharmacological approaches in the treatment of respiratory disorders, such as acetazolamide, theophylline, aminophylline, progesterone, nitric oxide. Possible effects of these drugs on the central respiratory network are discussed and putative therapeutic targets for the development of future pharmacological therapies suggested.

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“…Because the CPP is latent in adult rats, but remains intact, it was hypothesized that this pathway must have been active during development. A study using the in vitro, brainstem-spinal cord preparation showed that the CPP was active, not latent at birth (99). Ongoing studies are aimed at determining the development of the crossed phrenic pathway in vivo.…”

Section: Development Of the Crossed Phrenic Pathwaymentioning

confidence: 99%

Effect of Spinal Cord Injury on the Respiratory System: Basic Research and Current Clinical Treatment Options

Zimmer

Nantwi

Goshgarian

2007

The Journal of Spinal Cord Medicine

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151

126

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Summary: Spinal cord injury (SCI) often leads to an impairment of the respiratory system. The more rostral the level of injury, the more likely the injury will affect ventilation. In fact, respiratory insufficiency is the number one cause of mortality and morbidity after SCI. This review highlights the progress that has been made in basic and clinical research, while noting the gaps in our knowledge. Basic research has focused on a hemisection injury model to examine methods aimed at improving respiratory function after SCI, but contusion injury models have also been used. Increasing synaptic plasticity, strengthening spared axonal pathways, and the disinhibition of phrenic motor neurons all result in the activation of a latent respiratory motor pathway that restores function to a previously paralyzed hemidiaphragm in animal models. Human clinical studies have revealed that respiratory function is negatively impacted by SCI. Respiratory muscle training regimens may improve inspiratory function after SCI, but more thorough and carefully designed studies are needed to adequately address this issue. Phrenic nerve and diaphragm pacing are options available to wean patients from standard mechanical ventilation. The techniques aimed at improving respiratory function in humans with SCI have both pros and cons, but having more options available to the clinician allows for more individualized treatment, resulting in better patient care. Despite significant progress in both basic and clinical research, there is still a significant gap in our understanding of the effect of SCI on the respiratory system.

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Spontaneous crossed phrenic activity in the neonatal respiratory network

Cited by 19 publications

References 41 publications

Temperature and state dependence of dynamic phrenic oscillations in the decerebrate juvenile rat

Temperature and state dependence of dynamic phrenic oscillations in the decerebrate juvenile rat

Breathing Generation and Potential Pharmacotherapeutic Approaches to Central Respiratory Disorders

Effect of Spinal Cord Injury on the Respiratory System: Basic Research and Current Clinical Treatment Options

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