Microglia, the resident immune effective cells of the central nervous system, play crucial roles in mediating immune-related process. It becomes activated quickly in response to even minor pathological insults and participates in series of immune responses. Under physiological conditions, most microglia stay in a typical resting state, with ramified processes continuously extending and retracting from surrounding neural tissues, suggesting an important function of resting microglia. Recent studies indicate that resting microglia can regulate many physiological processes, including neural development, neural circuit formation, neuronal activity and plasticity, and animal grooming behavior. Here, we review the properties of resting microglia and further discuss how microglia participate in the above-mentioned functional regulation under physiological conditions.
Animals ; Central Nervous System ; cytology ; Humans ; Microglia ; immunology ; physiology

Central nervous system injury leads to irreversible neuronal loss and glial scar formation, which ultimately results in persistent neurological dysfunction. Regenerative medicine suggests that replenishing missing neurons may be an ideal approach to repair the damage. Recent researches showed that many mature cells could be transdifferentiated into functional neurons by reprogramming. Therefore, reprogramming endogenous glia in situ to produce functional neurons shows great potential and unique advantage for repairing neuronal damage and treating neurodegenerative diseases. The present review summarized the current research progress on in situ transdifferentiation in the central nervous system, focusing on the cell types, characteristics and research progress of glial cells that could be transdifferentiated in situ, in order to provide theoretical basis for the development of new therapeutic strategies of neuronal injury and further clinical application.
Cell Transdifferentiation ; Cellular Reprogramming ; Central Nervous System ; cytology ; Humans ; Neurodegenerative Diseases ; Neuroglia ; cytology ; Neurons ; cytology

Neurogenesis occurs in the adult brain, and neural stem cells (NSCs) reside in the adult central nervous system (CNS). In the adult brain, newly generated neuronal cells would originate from a population of glial cells with stem cells properties, and be involved in processes such as learning and memory, depression, and in regenerative attempts in the diseased brain and after injuries. In human, a recent study reported no evidence of migrating neural progenitor cells along the subventricular zone (SVZ) to the olfactory bulb (OB), contrary to other species, highlighting the particularity of adult neurogenesis in human. Though the origin and contribution of newly generated neuronal cells to CNS pathophysiology remain to be fully understood, the discovery that NSCs reside in the adult CNS force us to re-evaluate our knowledge and understanding of brain functioning, and suggest that the adult CNS may be amenable to repair. In this manuscript,we will review the recent data, debates and controversies on the identification, origin and function of newly generated neuronal cells in the adult brain, in human and in other species. We will discuss their contribution and significance to CNS pathophysiology, and for cellular therapy.
Adult Stem Cells ; cytology ; transplantation ; Aging ; Animals ; Brain ; cytology ; Central Nervous System ; cytology ; growth & development ; Central Nervous System Diseases ; pathology ; surgery ; Humans ; Stem Cell Transplantation ; methods

Neurons are the structural and functional unit of the nervous system. Precisely regulated dendrite morphogenesis is the basis of neural circuit assembly. Numerous studies have been conducted to explore the regulatory mechanisms of dendritic morphogenesis. According to their action regions, we divide them into two categories: the intrinsic and extrinsic regulators of neuronal dendritic morphogenesis. Intrinsic factors are cell type-specific transcription factors, actin polymerization or depolymerization regulators and regulators of the secretion or endocytic pathways. These intrinsic factors are produced by neuron itself and play an important role in regulating the development of dendrites. The extrinsic regulators are either secreted proteins or transmembrane domain containing cell adhesion molecules. They often form receptor-ligand pairs to mediate attractive or repulsive dendritic guidance. In this review, we summarize recent findings on the intrinsic and external molecular mechanisms of dendrite morphogenesis from multiple model organisms, including , and mice. These studies will provide a better understanding on how defective dendrite development and maintenance are associated with neurological diseases.
Animals ; Caenorhabditis elegans ; cytology ; Dendrites ; Mice ; Morphogenesis ; Nervous System Diseases ; physiopathology ; Neurons ; cytology ; Transcription Factors ; metabolism

Mesenchymal Stem Cell Transplantation ; Mesenchymal Stromal Cells ; cytology ; Nervous System Diseases ; surgery

There are two types of cells in the central nervous systems (CNS) of mammals-neurons and glia. The structure and function of neurons have been thoroughly studied; while the role of glia in information processing has not been systematically studied because they cannot produce action potentials like neuron. During the past decades, glial cells were considered to play a supportive role in CNS instead of information processing. Recently, a variety of studies suggest that glial cells are actively involved in the regulation of brain function associated with neurons. Glial cells, especially astrocytes play important roles in different sensory processing. In the present article, we review the role of astrocytes in sensory processing in the CNS.
Animals ; Astrocytes ; cytology ; physiology ; Central Nervous System ; physiology ; Humans ; Sensation ; physiology ; Synapses ; physiology

Slow transit constipation(STC)is the common type of chronic idiopathic constipation. Due to failure of routine conservative treatment, laxatives abuse is the most choice for majority of the patients, which could damage the enteric nervous system and result in aggravation of constipation. Resection of the slow transit colon is the ultimate option for some patients. It is hard to prevent and treat STC clinically because of the unknown pathophysiologic mechanism. Abnormalities of enteric neurotransmitters such as VIP, SP, NOS and decreased number of interstitial cells of Cajal have been described in the colon of the patients with STC. However, long term application of stimulant laxatives can also result in the almost same changes in the colon. Exploration of the potential relationship among the above reported abnormalities is the direction of future study.
Constipation ; physiopathology ; Enteric Nervous System ; physiopathology ; Gastrointestinal Transit ; physiology ; Humans ; Interstitial Cells of Cajal ; cytology

Volume transmission (VT) is a widespread mode of intercellular communication that occurs in the extracellular fluid (ECF) and in the cerebrospinal fluid (CSF) of the brain with VT signals moving from source to target cells via energy gradients leading to diffusion and convection (flow). The VT channels are diffuse forming a plexus in the extracellular space, while in wiring transmission (WT) the channels (axons, terminals) are private. The speed is slow (seconds-minutes) in VT while rapid in the millisecond range in WT. The extracellular space is the substrate for VT, which is modulated by the extracellular matrix. Extrasynaptic VT is linked to synaptic transmission and likely often takes place due to incomplete diffusion barriers with the synaptic transmitter reaching extrasynaptic domains of the pre-and post-synaptic membrane of the synapse, the astroglia, and even adjacent synapses. Indications exist for the existence of striatal D2-like receptor-mediated extrasynaptic form of dopamine (DA) VT at the local circuit level in vivo in the human striatum. Synaptic glutamate via extrasynaptic VT can act on extrasynaptic metabotropic glutamate receptors located on the astroglia leading to Ca(2+) mediated astrocytic glutamate release into the extracellular space (ECS). Long distance peptide VT and CSF VT is the major long distance VT with distances more than 1 mm and flow in the CSF. Indications for long distance VT of beta-endorphin and oxytocin are obtained. We propose that monogamy in the female prairie vole may take place through an increase in oxytocin VT, especially in nucleus accumbens. Release of extracellular vesicles containing receptors, proteins, RNAs and mtDNA from cellular networks in the central nervous system (CNS) into the ECF and CSF may be a fundamental communication in the CNS. It represents a special form of volume transmission, the Roamer subtype of VT. It may greatly contribute to dynamic events of synaptic plasticity but also to spread of pathological proteins in protein conformational disorders. VT also occurs in the peripheral nervous system and associated cells. Short and long distance VT may take place in meridian channels via diffusion and flow in the interstitial fluid. Acupuncture can produce VT signals by releasing transmitters and modulators from nerve terminals and mast cells.
Animals ; Cell Communication ; Central Nervous System ; cytology ; Extracellular Space ; metabolism ; Humans ; Synapses ; metabolism

Initially, when periaqueductal gray (PAG) is electrically stimulated, analgesia is induced, and this phenomenon is called stimulation-produced analgesia. Nucleus raphe magnus (NRM) as well as PAG are known to be the potent analgesic centers. NRM could modulate the nociceptive response of spinal cord neurons through spinally projecting fibers. However, as well as the above analgesic effects have been confined to the somatic pain, it was variable according to species, and the analgesic effect by NRM stimulation on the visceral pain was not yet clarified. In this study the analgesic effect by NRM stimulation on the visceral pain was examined through recording the activities of the dorsal horn neurons with renal input and renal pain, as a type of visceral pain. The renal pain was induced by ureteral occlusion or renal arterial occlusion, which in turn activated the renal mechanoreceptor or chemoreceptor. These cells had concomitant somatic input. In order to compare the effects of NRM stimulation on the renal pain with somatic pain, the somatic stimulation such as squeezing was conducted on the peripheral receptive field. The main results are summarized as follows: 1) After an electrical stimulation of NRM, spontaneous activities of dorsal horn neurons with renal input were reduced to 73.3 +/- 9.7% of the control value. 2) After an electrical stimulation of NRM, activities of dorsal horn neurons with renal input evoked by a brush, a type of non-noxious stimuli, did not change significantly. But the activities by a squeeze, a type of noxious stimuli, the activities were reduced to 63.2 +/- 7.2% of the control value. 3) After an electrical stimulation of NRM, activities of dorsal horn neurons with renal input evoked by occlusion of ureter or renal artery were reduced to 46.7 +/- 8.8% and 49.0 +/- 8.0% of the control value respectively. 4) The inhibitory effect of NRM on the dorsal horn neurons with renal input did not show any difference between renal A delta fiber and C fiber group. 5) By the electrical stimulation of NRM, the activities evoked by ureteral occlusion showed more reduction in the high threshold cell group than in the wide dynamic range cell group. These results suggest that activation of NRM can alleviate the renal pain as well as the somatic pain by modulating the dorsal horn neurons activities.
Afferent Pathways/cytology/physiology ; Animal ; Cats ; Electric Stimulation ; Female ; Kidney/innervation/*physiopathology ; Male ; Nervous System/cytology ; Nervous System Physiology ; Neurons/physiology ; *Pain Threshold ; Raphe Nuclei/*physiology ; Spinal Cord/cytology/physiology ; Support, Non-U.S. Gov't

All of neural stem cell within the central nervous system and derived from transplantation or embryonic stem cell have the ability of differentiating into various kinds of neural cells. Regeneration of neural cells plays a critical role on function recovery damaged central nervous system (CNS). Advances in repairing of injury in central nervous system with neural stem cell and embryonic stem cell in recent years are reviewed in this article.
Adult Stem Cells ; cytology ; Animals ; Central Nervous System Diseases ; physiopathology ; surgery ; Embryonic Stem Cells ; cytology ; Humans ; Nerve Regeneration ; physiology ; Neuronal Plasticity ; Neurons ; cytology ; Stem Cell Transplantation