The mechanisms controlling pain in newborns during delivery are poorly understood. We explored the hypothesis that oxytocin, an essential hormone for labor and a powerful neuromodulator, exerts analgesic actions on delivery. Using thermal tail-flick assay, we report sensitivity is two-fold lower rat pups immediately after birth than 2 days later. Oxytocin receptor antagonists strongly enhanced newborn, but not 2-day-old rats, whereas oxytocin reduced at both ages suggesting endogenous...

In clinics, physical injuries to the spinal cord cause a temporary motor areflexia below lesion, known as shock. This topic is still underexplored due lack of preclinical injury (SCI) models that do not use anesthesia, which would affect excitability. Our innovative design considered custom-made micro impactor provides localized and calibrated strikes ventral surface thoracic entire CNS isolated from neonatal rats. Before after injury, multiple root (VR) recordings continuously traced...

Abstract Moderate and acute intermittent hypoxia (IH) facilitates respiration in adults, mostly by recruiting peripheral chemo‐/baroreceptors. As central chemoreceptors are widely expressed immature brains, we hypothesized that IH modulates at birth through a purely neurogenic mechanism involving the hypothalamus. The nervous system (CNS) isolated from 0‐ to 3‐day‐old rats was perfused with four eight brief (5 min) bouts of mild‐hypoxic/normocapnic modified Krebs solution, intermingled 5‐min...

During antenatal development, the operation and maturation of mammalian spinal networks strongly depend on activity ventral horn GABAergic interneurons that mediate excitation first inhibition later. Although functional consequence GABA actions may maturational processes in target neurons, it is also likely evolving changes transmission require fine-tuning release, probably via certain intrinsic mechanisms regulating neuron excitability at different embryonic stages. Nevertheless, has not...

Abstract Several spinal motor output and essential rhythmic behaviors are controlled by supraspinal structures, although their contribution to neuronal networks for respiration locomotion at birth still requires better characterization. As preparations of isolated brainstem only focus on local circuitry, we introduced the in vitro central nervous system (CNS) from neonatal rodents simultaneously record a stable respiratory rhythm both cervical lumbar ventral roots (VRs). Electrical pulses...

Potentiation of synaptic activity in spinal networks is reflected the magnitude modulation motor responses evoked by and cortical input. After cord injury, can be facilitated pairing peripheral nerve stimuli.To facilitate potentiation cortico-spinal input with epidural electrical stimulation, we designed a novel neuromodulation method called dynamic stimulation (DS), using patterns derived from hind limb EMG signal during stepping.DS was applied dorsally to lumbar enlargement through...

The spinal cord contains an intrinsic locomotor program driven by a central pattern generator that rhythmically activates flexor and extensor limb motor pools. Although long-lasting activity can be generated pharmacologically, trains of afferent stimuli trigger only few cycles. present study investigated whether new electrical stimulation protocol (termed FL istim) could elicit fictive locomotion (FL) in the rat vitro. Thus, after first inducing bath application N-methyl-d-aspartate...

Abstract The role of group I metabotropic glutamate receptors (mGluRs), and their subtypes 1 or 5, in rhythmic patterns generated by the neonatal rat spinal cord was investigated. Fictive locomotor induced N ‐methyl‐ d ‐aspartate + serotonin were slowed down subtype antagonists ( RS )‐1‐aminoindan‐1,5‐dicarboxylic acid (AIDA) 7‐(hydroxyimino)cyclopropa[b]chromen‐1a‐carboxylate ethyl ester (CPCCOEt) unaffected 5 antagonist 2‐methyl‐6‐(phenylethynyl)pyridine hydrochloride (MPEP). agonist...

Abstract It is unclear how a localized spinal cord injury may acutely affect locomotor networks of segments initially spared by the lesion. To investigate process secondary damage following injury, we used in vitro model neonatal rat isolated with transverse barriers at low thoracic–upper lumbar region to allow focal application kainate hypoxic and aglycemic solution (with reactive oxygen species). The time‐course nature changes downstream lesion site were investigated over first 24 h,...

The tolerance of breathing in neonates to oxygen depletion is reflected by persistence inspiratory‐related motor output during sustained anoxia newborn rat brainstem preparations. It not known whether lumbar networks innervating expiratory abdominal muscles are, contrast, inhibited similar locomotor neonatal mouse cords. To test this, we recorded cervical/hypoglossal plus pre/postinspiratory lumbar/facial nerve activities and, sometimes simultaneously, rhythms brainstem–spinal Chemical...

Abstract Exercise modifies respiratory functions mainly through the afferent feedback provided by exercising limbs and descending input from suprapontine areas, two contributions that are still underestimated in vitro. To better characterize role of limb afferents modulating respiration during physical activity, we designed a novel experimental vitro platform. The whole central nervous system was isolated neonatal rodents kept with hindlimbs attached to an ad-hoc robot (Bipedal Induced...

Synergizing the effect of afferent fibre stimulation with pharmacological interventions is a desirable goal to trigger spinal locomotor activity, especially after injury. Thus, better understand mechanisms optimize this process, we studied role neuropeptide oxytocin (previously shown stimulate networks) on network and motoneuron properties using isolated neonatal rat cord. On motoneurons (1 nM-1 μM) generated sporadic bursts superimposed firing dose-dependent depolarization. No...

Abstract In clinics, physical injuries to the spinal cord cause a temporary motor areflexia below lesion, known as shock. This topic is still underexplored due lack of preclinical SCI models that do not use anesthesia, which would affect excitability. Our innovative design considered custom-made micro impactor provides localized and calibrated strikes ventral surface thoracic entire CNS isolated from neonatal rats. Before after injury, multiple root (VR) recordings continuously traced...

Abstract While group I glutamate metabotropic (mGlu) receptors show discrete neuronal distribution in the neonatal rat spinal cord, functional role of their distinct receptor subtypes remains uncertain. Intracellular recording from lumbar motoneurons together with extracellular ventral root (VR) responses was used to investigate differential contribution by mGlu cell excitability and network activity. The agonist DHPG evoked motoneuron depolarization (via AIDA or CPCCOEt‐sensitive subtype 1)...