Depression by Ca2+ and Stimulation by K+ of Fictive Inspiratory Rhythm in Newborn Rat Brainstem Slices

Panaitescu, Bogdan; Ruangkittisakul, Araya; Ballanyi, Klaus

doi:10.1007/978-1-4419-5692-7_19

Cited by 3 publications

(2 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This aCSF solution is commonly used to study the operation of locomotor rhythm-generating networks in isolated spinal cord preparation [21]–[24]. In these conditions, however, the elevated extracellular concentration of calcium (2 mM) induces a low baseline respiratory rate as observed in our experiments [25], [26]. Nevertheless, this reduced excitability is required to simultaneously record inspiratory- and expiratory-related motor activities for more than 2.5 hours (time necessary to achieve some of our protocols).…”

Section: Methodsmentioning

confidence: 60%

Remote Control of Respiratory Neural Network by Spinal Locomotor Generators

et al. 2014

View full text Add to dashboard Cite

During exercise and locomotion, breathing rate rapidly increases to meet the suddenly enhanced oxygen demand. The extent to which direct central interactions between the spinal networks controlling locomotion and the brainstem networks controlling breathing are involved in this rhythm modulation remains unknown. Here, we show that in isolated neonatal rat brainstem-spinal cord preparations, the increase in respiratory rate observed during fictive locomotion is associated with an increase in the excitability of pre-inspiratory neurons of the parafacial respiratory group (pFRG/Pre-I). In addition, this locomotion-induced respiratory rhythm modulation is prevented both by bilateral lesion of the pFRG region and by blockade of neurokinin 1 receptors in the brainstem. Thus, our results assign pFRG/Pre-I neurons a new role as elements of a previously undescribed pathway involved in the functional interaction between respiratory and locomotor networks, an interaction that also involves a substance P-dependent modulating mechanism requiring the activation of neurokinin 1 receptors. This neurogenic mechanism may take an active part in the increased respiratory rhythmicity produced at the onset and during episodes of locomotion in mammals.

show abstract

Section: Methodsmentioning

confidence: 60%

Remote Control of Respiratory Neural Network by Spinal Locomotor Generators

et al. 2014

View full text Add to dashboard Cite

show abstract

“…We suspect that the composition of the ACSF, with a substantially lower extracellular calcium concentration (0.8 m m ) than normally used, may have uncovered the novel activity. Low extracellular calcium was used to increase excitability of the preparations used here (Rekling et al 1996; Panaitescu et al 2010), which otherwise would not produce spontaneous respiratory activity (Jean‐Charles & Gerard, 2002).…”

Section: Discussionmentioning

confidence: 99%

Population calcium imaging of spontaneous respiratory and novel motor activity in the facial nucleus and ventral brainstem in newborn mice

Persson

Rekling

2011

The Journal of Physiology

View full text Add to dashboard Cite

Non-technical summary The brainstem contains neural circuits that control breathing. Groups of neurons produce the rhythm of inspiration and expiration, and other groups produce the motor output that controls respiratory muscles. One such group of neurons is the facial nucleus, which controls muscles in the face. Here we show, using electrical and calcium imaging techniques, that different subregions within the facial nucleus are particularly active during breathing, which suggest an involvement in keeping the airway open during inspiration. Furthermore, the experiments show that a novel rhythm generating circuit is present in the brainstem. These results may help us to a better understanding of how the brainstem controls breathing and other motor behaviours in the upper body.Abstract The brainstem contains rhythm and pattern forming circuits, which drive cranial and spinal motor pools to produce respiratory and other motor patterns. Here we used calcium imaging combined with nerve recordings in newborn mice to reveal spontaneous population activity in the ventral brainstem and in the facial nucleus. In Fluo-8 AM loaded brainstem-spinal cord preparations, respiratory activity on cervical nerves was synchronized with calcium signals at the ventrolateral brainstem surface. Individual ventrolateral neurons at the level of the parafacial respiratory group showed perfect or partial synchrony with respiratory nerve bursts. In brainstem-spinal cord preparations, cut at the level of the mid-facial nucleus, calcium signals were recorded in the dorsal, lateral and medial facial subnuclei during respiratory activity. Strong activity initiated in the dorsal subnucleus, followed by activity in lateral and medial subnuclei. Whole-cell recordings from facial motoneurons showed weak respiratory drives, and electrical field potential recordings confirmed respiratory drive to particularly the dorsal and lateral subnuclei. Putative facial premotoneurons showed respiratory-related calcium signals, and were predominantly located dorsomedial to the facial nucleus. A novel motor activity on facial, cervical and thoracic nerves was synchronized with calcium signals at the ventromedial brainstem extending from the level of the facial nucleus to the medulla-spinal cord border. Cervical dorsal root stimulation induced similar ventromedial activity. The medial facial subnucleus showed calcium signals synchronized with this novel motor activity on cervical nerves, and cervical dorsal root stimulation induced similar medial facial subnucleus activity. In conclusion, the dorsal and lateral facial subnuclei are strongly respiratory-modulated, and the brainstem contains a novel pattern forming circuit that drives the medial facial subnucleus and cervical motor pools.

show abstract

Bimodal Respiratory–Locomotor Neurons in the Neonatal Rat Spinal Cord

et al. 2016

View full text Add to dashboard Cite

Neural networks that can generate rhythmic motor output in the absence of sensory feedback, commonly called central pattern generators (CPGs), are involved in many vital functions such as locomotion or respiration. In certain circumstances, these neural networks must interact to produce coordinated motor behavior adapted to environmental constraints and to satisfy the basic needs of an organism. In this context, we recently reported the existence of an ascending excitatory influence from lumbar locomotor CPG circuitry to the medullary respiratory networks that is able to depolarize neurons of the parafacial respiratory group during fictive locomotion and to subsequently induce an increased respiratory rhythmicity (Le Gal et al., 2014b). Here, using an isolated in vitro brainstem-spinal cord preparation from neonatal rat in which the respiratory and the locomotor networks remain intact, we show that during fictive locomotion induced either pharmacologically or by sacrocaudal afferent stimulation, the activity of both thoracolumbar expiratory motoneurons and interneurons is rhythmically modulated with the locomotor activity. Completely absent in spinal inspiratory cells, this rhythmic pattern is highly correlated with the hindlimb ipsilateral flexor activities. Furthermore, silencing brainstem neural circuits by pharmacological manipulation revealed that this locomotor-related drive to expiratory motoneurons is solely dependent on propriospinal pathways. Together these data provide the first evidence in the newborn rat spinal cord for the existence of bimodal respiratory-locomotor motoneurons and interneurons onto which both central efferent expiratory and locomotor drives converge, presumably facilitating the coordination between the rhythmogenic networks responsible for two different motor functions.

show abstract

Depression by Ca2+ and Stimulation by K+ of Fictive Inspiratory Rhythm in Newborn Rat Brainstem Slices

Cited by 3 publications

References 12 publications

Remote Control of Respiratory Neural Network by Spinal Locomotor Generators

Remote Control of Respiratory Neural Network by Spinal Locomotor Generators

Population calcium imaging of spontaneous respiratory and novel motor activity in the facial nucleus and ventral brainstem in newborn mice

Bimodal Respiratory–Locomotor Neurons in the Neonatal Rat Spinal Cord

Contact Info

Product

Resources

About