Raphe modulation of the pre-Bötzinger complex respiratory bursts in in vitro medullary half-slice preparations of neonatal mice.

Spontaneous respiratory bursts which begin in the pre-Bötzinger complex were recorded from the hypoglossal (XIIth) nerve rootlets of in vitro slices prepared from newborn mice. First, we examined the respiratory bursts before and after a midline or para-midline transection which spared the caudal raphe nuclei: the raphe obscurus and raphe pallidus. After a midline transection, the respiratory bursts in both half-slices were desynchronized and had slightly decreased amplitudes and frequencies.

Spontaneous respiratory rhythm generation in in vitro upper cervical slice preparations of neonatal mice.

Isolated upper cervical slice preparations were prepared from neonatal mice to examine whether spontaneous respiratory activity could be generated in the preparations. By using brainstem-spinal cord preparations, we first recorded from the cervical C1-C2 and C4 ventral roots rhythmic bursts which were synchronized with respiratory burst activity of the hypoglossal (XIIth) nerve. Following transection just above the C1 segment, smaller and slower rhythmic bursts still persisted in the C1/C2 ventral roots and these were synchronized with those in the C4 ventral root.

Involvement of medullary GABAergic and serotonergic raphe neurons in respiratory control: electrophysiological and immunohistochemical studies in rats.

In the present study we first examined the possible involvement of the putative neurotransmitters gamma-aminobutyric acid (GABA) and serotonin (5-HT) in raphe-induced facilitatory or inhibitory effects on the respiratory activity of rats. Secondly, we investigated the possibility of spinal projections of GABAergic and serotonergic neurons from the medullary raphe nuclei to the phrenic motor nucleus (PMN). We observed that an intravenous (i.

Effects of electrical stimulation of the medullary raphe nuclei on respiratory movement in rats.

The present study was undertaken to examine the effects of electrical stimulation of the medullary raphe nuclei on respiration in rats anesthetized with ketamine and xylazine. Train pulse stimuli (100 Hz, 10-30 microA) were applied in the regions of the caudal raphe nuclei: the raphe magnus (RM), raphe pallidus (RP) and raphe obscurus (RO). Stimulation of the RM depressed inspiratory movements measured by means of an abdominal pneumograph, whereas stimulation of the RP augmented inspiratory movements.

Comparison of midazolam effects on inhibitory postsynaptic currents in hippocampal CA3 with those in CA1.

We compared the effects of midazolam, one of the popular benzodiazepines, on inhibitory postsynaptic currents in CA3 pyramidal cells with those in CA1 pyramidal cells in rat hippocampal slices. With all of the midazolam concentrations tested, the conductance of the evoked inhibitory postsynaptic current of the CA3 and CA1 pyramidal cells was significantly larger than the control, and increased in a dose-dependent manner. The normalized conductance of the inhibitory postsynaptic currents of the CA3 and CA1 pyramidal cells was not significantly different.

Lumbar commissural interneurons with reticulospinal inputs in the cat: morphology and discharge patterns during fictive locomotion.

The purpose of this study was 1). to characterize the morphology of lumbar commissural neurons (CNs) with reticulospinal inputs and 2). to quantitate their activity during locomotor rhythm generation.

Differential effects of midazolam on inhibitory postsynaptic currents in CA1 pyramidal cells and dentate gyrus granule cells of rat hippocampal slices.

To examine regional differences of synaptic transmission, the effects of midazolam were observed on inhibitory postsynaptic currents (IPSCs) in CA1 pyramidal cells (CA1-PCs) and dentate gyrus granule cells (DG-GCs) in rat hippocampal slices. Midazolam is one of the most popular benzodiazepines. The monosynaptic IPSCs in the CA1-PCs and DG-GCs were evoked by electrical stimulation of GABAergic interneurons and recorded by whole cell patch-clamp techniques.

Locomotor role of the corticoreticular-reticulospinal-spinal interneuronal system.

In vertebrates, the descending reticulospinal pathway is the primary means of conveying locomotor command signals from higher motor centers to spinal interneuronal circuits, the latter including the central pattern generators for locomotion. The pathway is morphologically heterogeneous, being composed of various types of inparallel-descending axons, which terminate with different arborization patterns in the spinal cord. Such morphology suggests that this pathway and its target spinal interneurons comprise varying types of functional subunits, which have a wide variety of functional roles, as dictated by command signals from the higher motor centers.

Identification of Respiratory Neurons Regenerating Axons into Peripheral Nerve Grafts in Adult Rats.

The present aimed to identify the origin of medullary and upper cervical respiratory neurons regenerating their axons into the peripheral nerve grafts in adult rats. We employed an antidromic activation technique and a retrograde horseradish peroxidase (HRP) tracing method for determining the origins of the regenerating axons. Autologous segments of the common peroneal nerve were successfully implanted ventrolaterally into the proximal cut end of the C2 spinal cord hemisection (n = 24).