Little is known about how gap junctions are involved in the respiratory-related or other types of physiological neuronal activity since physiologically active gap junction currents (GJCs) have never been characterized from single respiratory-related neurons or from single neurons of any other types. In the present study we hypothesized that GJCs could be selectively revealed from single neurons by elimination of transmembrane electrochemical gradients in voltage patch-clamp recording, and this hypothesis was tested in single inspiratory tracheal preganglionic vagal motor neurons (I-TPVMs). The results showed that GJCs were selectively revealed in all I-TPVMs when the transmembrane electrochemical gradients were eliminated in voltage patch-clamp recording, and were rhythmically activated by central inspiratory activity. Therefore, this method may be used as a fast way to detect GJCs within spontaneously active neuronal networks.
Gap Junctions ; physiology ; Motor Neurons ; physiology ; Patch-Clamp Techniques ; Trachea ; cytology

Spinal cord injury (SCI), which is much in the public eye, is still a refractory disease compromising the well-being of both patients and society. In spite of there being many methods dealing with the lesion, there is still a deficiency in comprehensive strategies covering all facets of this damage. Further, we should also mention the structure called the corticospinal tract (CST) which plays a crucial role in the motor responses of organisms, and it will be the focal point of our attention. In this review, we discuss a variety of strategies targeting different dimensions following SCI and some treatments that are especially efficacious to the CST are emphasized. Over recent decades, researchers have developed many effective tactics involving five approaches: (1) tackle more extensive regions; (2) provide a regenerative microenvironment; (3) provide a glial microenvironment; (4) transplantation; and (5) other auxiliary methods, for instance, rehabilitation training and electrical stimulation. We review the basic knowledge on this disease and correlative treatments. In addition, some well-formulated perspectives and hypotheses have been delineated. We emphasize that such a multifaceted problem needs combinatorial approaches, and we analyze some discrepancies in past studies. Finally, for the future, we present numerous brand-new latent tactics which have great promise for curbing SCI.
Animals ; Astrocytes/cytology* ; Axons/physiology* ; Cell Transplantation ; Disease Models, Animal ; Electric Stimulation ; Humans ; Microglia/cytology* ; Motor Neurons/cytology* ; Nerve Regeneration ; Neuroglia/cytology* ; Neuronal Plasticity ; Neurons/cytology* ; Oligodendroglia/cytology* ; Pyramidal Tracts/pathology* ; Recovery of Function ; Regenerative Medicine/methods* ; Spinal Cord Injuries/therapy*

OBJECTIVETo investigate the effects of combined transplantation of neural stem cells (NSC) and olfactory ensheathing cells (OEC) on the motor function of rats with intracerebral hemorrhage.

METHODSIn three days after a rat model of caudate nucleus hemorrhage was established, NSCs and OEC, NSC, OEC (from embryos of Wistar rats) or normal saline were injected into hematomas of rats in combined transplantation group, NSC group, OEC group, and control group, respectively. Damage of neural function was scored before and in 3, 7, 14, 30 days after operation. Tissue after transplantation was observed by immunocytochemistry staining.

RESULTSThe scores for the NSC, OEC and co-transplantation groups were significantly lower in 14 and 30 days after operation than in 3 days after operation (P < 0.05). The scores for the NSC and OEC groups were significantly lower than those for the control group only in 30 days after operation (P < 0.05), while the difference for the NSC-OEC group was significant in 14 days after operation (P < 0.05). Immunocytochemistry staining revealed that the transplanted OEC and NSC could survive, migrate and differentiate into neurons, astrocytes, and oligodendrocytes. The number of neural precursor cells was greater in the NSC and combined transplantation groups than in the control group. The number of neurons differentiated from NSC was significantly greater in the co-transplantation group than in the NSC group.

CONCLUSIONCo-transplantation of NSC and OEC can promote the repair of injured tissue and improve the motor function of rats with intracerebral hemorrhage.

Animals ; Cerebral Hemorrhage ; therapy ; Embryonic Stem Cells ; physiology ; Male ; Motor Activity ; physiology ; Motor Neurons ; transplantation ; Myelin Sheath ; transplantation ; Nerve Regeneration ; physiology ; Neurons ; cytology ; transplantation ; Olfactory Nerve ; cytology ; Rats ; Rats, Wistar ; Recovery of Function ; physiology ; Stem Cell Transplantation

The aim of the present study is to observe the receptor kinetics property of long-term potentiation (LTP) of excitatory postsynaptic potential (EPSP) in spinal cord motoneurons (MNs) by descending activation. The intracellular recording techniques were conducted in spinal cord MNs of neonatal rats aged 8-14 days. The changes of EPSP induced by ipsilateral ventrolateral funiculus (iVLF) stimulation (iVLF-EPSPs) were observed, and receptor kinetics of iVLF-EPSPs were analyzed. The results showed that, the amplitude, area under curve and maximum left slope of EPSP were positively correlated with stimulus intensity (P < 0.05 or P < 0.01), while the apparent receptor kinetic parameters apparent dissociation rate constant (K(2)), apparent equilibrium dissociation constant (K(T)) of EPSP were negatively correlated with stimulus intensity (P < 0.01 or P < 0.05). The iVLF-EPSPs were persistently increased after tetanic stimulation (100 Hz, 50 pulses/train, duration 0.4-1.0 ms, 6 trains, main interval 10 s, 10-100 V) in 5 of 11 tested MNs. The amplitude of iVLF-EPSPs was potentiated to more than 120% of baseline and lasted at least 30 min, which could be referred to as iVLF-LTP. Meanwhile, the area under curve and maximum left slope of EPSPs were also increased to more than 120% of baseline. During iVLF-LTP, apparent receptor kinetics analyses of iVLF-EPSPs indicated that K(2) and KT were decreased significantly to less than 80% of the baseline within 10 min and gradually and partially recovered in 3 MNs. These results of receptor kinetics analyses of iVLF-EPSPs suggest a possible enhancement in affinity of postsynaptic receptors in the early stage of iVLF-LTP in some MNs.
Animals ; Excitatory Postsynaptic Potentials ; Kinetics ; Long-Term Potentiation ; Motor Neurons ; physiology ; Rats ; Spinal Cord ; cytology ; Synaptic Transmission

OBJECTIVETo study the relationship between the protection of Ginsenoside(GS) for spinal cells and nitric oxide (NO).

METHODSpinal cells were cultured in vitro, the model of peripheral nerve was established by scarifying the cells, and NO was measured by Griess method.

RESULTNO in injury group was high than that in noninjury group and NO in group cultured by GS was less than that in group cultured by common medium.

CONCLUSIONNO increases when peripheral nerve is injuried, and the protective effect of GS on spinal cells may be through inhibiting NO release.

Animals ; Cells, Cultured ; Fetus ; Ginsenosides ; isolation & purification ; pharmacology ; Motor Neurons ; cytology ; drug effects ; metabolism ; Neurons, Afferent ; cytology ; drug effects ; metabolism ; Neuroprotective Agents ; pharmacology ; Nitric Oxide ; metabolism ; Panax ; chemistry ; Plants, Medicinal ; chemistry ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; cytology ; metabolism

AIMTo investigate the effect of acute exhaustive exercise on gastrointestinal motility and its enteric nervous mechanisms.

METHODS24 rats were randomly divided into control group (C) and acute exhaustive exercise group (AEE). The rate of gastrointestinal transit was measured and histologic changes of nitriergic nerves in ileum myenteric plexus were observed with enzymatic histochemical and image analytic technique.

RESULTSIn the rats of AEE group, the rate of gastrointestinal transit was delayed comparing with C group (P < 0.05), the numbers of nitrergic neurons and expression levels of nitric oxide synthase (NOS) in the ileum myenteric plexus significantly increased comparing with C group (P < 0.01).

CONCLUSIONIt is possible that increase of nitrergic neurons and expression levels of NOS in the myenteric plexus of small intestine are one of the mechanisms of delay of gastrointestinal transit rate in acute exhaustive exercise rats.

Animals ; Gastrointestinal Motility ; physiology ; Gastrointestinal Transit ; physiology ; Ileum ; innervation ; Male ; Motor Activity ; Myenteric Plexus ; metabolism ; Nitrergic Neurons ; cytology ; Nitric Oxide Synthase ; metabolism ; Rats ; Rats, Sprague-Dawley

AIMThe protecting effect of human-derived neurotrophin-6 (NT-6) on injured neurons was investigated to test the neurobiological characteristics of human-derived NT-6.

METHODSAdult SD rats were used and divided into two groups, normal control group and experiment group. The right facial nerve of the experimental rats was sectioned. The experimental animals were subdivided into three groups, blank control group, NT-6 group and saline control group. The rats were raised for two weeks. Brain stem of the rats was removed and transversely sliced. Nissle stain and ChAT immunohistochemical stain of the slices were carried out to observe the role of NT-6 in protecting facial motoneurons.

RESULTSThe number of the ChAT positive neurons and the intensity of Nissle stain in the facial nucleus of NT-6 group were significantly augmented compared with that of the blank and saline control groups.

CONCLUSIONThe human-derived NT-6 could partially protect the facial motoneurons from retrograde degeneration induced by their axon damage.

Animals ; Disease Models, Animal ; Facial Nerve ; cytology ; Humans ; Motor Neurons ; drug effects ; pathology ; Nerve Growth Factors ; pharmacology ; Neuroprotective Agents ; pharmacology ; Rats ; Rats, Sprague-Dawley

Axotomy of the vagal motor neurons by cervical vagotomy induces NADPH diaphorase staining due to increased nitric oxide synthase expression in both the rat dorsal motor nucleus and nucleus ambiguous; furthermore, cerical vagotomy leads to cell death of the dorsal motor nucleus cells. Subdiaphragmatic vagotomy axotomizes the vagal motor cells further from the brainstem than cervical vagotomy, and cuts the fibers running only to the abdominal viscera. Here we report that subdiaphragmatic vagotomy is sufficient to induce NADPH diaphorase staining in the dorsal motor nucleus but does not induce staining in the nucleus ambiguus. Because the neurons of the dorsal motor nucleus do not undergo cell death after subdiaphragmatic vagotomy and are able to re-enervate the gut, the increased nitric oxide synthase expression after distal axotomy may be related more to regeneration than degeneration.
Animal ; Fourth Ventricle/physiology* ; Fourth Ventricle/enzymology* ; Fourth Ventricle/cytology ; Male ; Motor Neurons/enzymology ; NADPH Dehydrogenase/metabolism* ; Rats ; Rats, Sprague-Dawley ; Vagotomy/methods* ; Vagus Nerve/physiology*

Animals ; Embryo Culture Techniques ; Embryo, Mammalian ; Female ; Ganglia, Spinal ; cytology ; drug effects ; Glial Cell Line-Derived Neurotrophic Factor ; pharmacology ; Male ; Motor Neurons ; drug effects ; Neurons, Afferent ; drug effects ; Rats ; Rats, Sprague-Dawley

The cloned TWIK-related acid-sensitive K(+) channel (TASK-1) is sensitive to the pH changes within physiological pH range (pK~7.4). Recently, the native TASK-1-like channel was suggested to be the main contributor to the background (or leak) K(+) conductance in the motoneurons of the brain stem. Serotonin (5-HT) and variation of pH value in perfused solution could modulate these currents. Here we aimed to examine the properties and modulation of the currents by serotonin or variation of pH value in hypoglossal motoneurons of rats. Transverse slices were prepared from the brainstem of neonatal Sprague-Dawley rats (postnatal days 7-8). Hypoglossal motoneurons were used for the study. The leak K(+) current (TASK-1-like current) and hyperpolarization-activated cationic current (I(h)) were recorded with the whole-cell patch-clamp technique. The results showed that these currents were inhibited by acidified artificial cerebrospinal fluid (ACSF, pH 6.0) and activated by alkalized ACSF (pH 8.5). 5-HT (10 mumol/L) significantly inhibited both leak K(+) current and I(h) with depolarization of membrane potential and the occurrence of oscillation and/or spikes. Bath application of Ketanserine, an antagonist of 5-HT₂ receptor, reversed or reduced the inhibitory effect of acidified solution on leak K(+) current and I(h). The results suggest that 5-HT₂ receptors mediate the effects of acidified media on leak K(+) current and I(h) in hypoglossal motoneurons.
Animals ; Animals, Newborn ; Brain Stem ; cytology ; Hypoglossal Nerve ; cytology ; In Vitro Techniques ; Ion Transport ; Membrane Potentials ; Motor Neurons ; metabolism ; Patch-Clamp Techniques ; Potassium Channels, Tandem Pore Domain ; metabolism ; Rats ; Rats, Sprague-Dawley ; Serotonin ; pharmacology