Animals ; Neurotransmitter Agents ; metabolism ; Rabbits ; Syncope, Vasovagal ; metabolism ; physiopathology

OBJECTIVEThis review discusses the current status and progress in studies on the roles of hydrogen sulfide (H(2)S) in regulation of neurotoxicity, neuroprotection, and neuromodulator, as well as its therapeutic potential for neurodegenerative disorders.

DATA SOURCESThe data used in this review were mainly from Medline and PubMed published in English from 2001 to August 2011. The search terms were "hydrogen sulfide", "neuron", and "neurodegenerative disorders".

STUDY SELECTIONArticles regarding the regulation of neuronal function, the protection against neuronal damage and neurological diseases, and their possible cellular and molecular mechanisms associated with H(2)S were selected.

RESULTSThe inhibited generation of endogenous H(2)S is implicated in 1-methy-4-phenylpyridinium ion, 6-OHDA, and homocysteine-triggered neurotoxicity. H(2)S elicits neuroprotection in Alzheimer's disease and Parkinson's disease models as well as protecting neurons against oxidative stress, ischemia, and hypoxia-induced neuronal death. H(2)S offers anti-oxidant, anti-inflammatory and anti-apoptotic effects, as well as activates ATP-sensitive potassium channels and cystic fibrosis transmembrane conductance regulator Cl- channels. H(2)S regulates the long-term potentiation (LTP) and GABAB receptors in the hippocampus, as well as intracellular calcium and pH homeostasis in neurons and glia cells.

CONCLUSIONSThese articles suggest that endogenous H(2)S may regulate the toxicity of neurotoxin. H(2)S not only acts as a neuroprotectant but also serves as a novel neuromodulator.

Animals ; Humans ; Hydrogen Sulfide ; metabolism ; Nervous System ; metabolism ; Neuroprotective Agents ; metabolism ; Neurotoxins ; metabolism ; Neurotransmitter Agents ; metabolism

Seizures are a frequent symptom in metabolic disorders, although metabolic disorders are rarely found to be the cause of epilepsy. A precise diagnosis might not only influence treatment, but it might also call for counseling of the family, even if there are no direct therapeutic consequences. We review the main characteristics of epilepsy in metabolic disorders with regard to energy metabolism, toxic effects, neurotransmitters, and vitamins.
Counseling ; Energy Metabolism ; Epilepsy ; Humans ; Neurotransmitter Agents ; Seizures ; Vitamins

Neurotransmitters play an important role in nervous system. Temporal and spatial changes of neurotransmitter distribution are crucial to information processing in neural networks. Biosensors that can visually monitor neurotransmitters are one of the vital tools to explore a variety of physiological and pathological activities. This article reviews recent advances in monitoring neurotransmitters with high temporal and spatial resolution, and introduces the latest fluorescent imaging methods for typical neurotransmitters, including glutamate, dopamine, γ-aminobutyric acid and acetylcholine. The article also summarizes the basic principles, advantages and disadvantages of various visually detection methods, and provides systematic suggestions for designing neurotransmitter sensors with high temporal and spatial resolution.
Animals ; Biosensing Techniques ; instrumentation ; trends ; Fluorescence ; Humans ; Neurotransmitter Agents ; metabolism

Amino Acids ; metabolism ; Hepatic Encephalopathy ; therapy ; Humans ; Intestines ; metabolism ; Liver, Artificial ; Neurotransmitter Agents ; metabolism

OBJECTIVETo develop a high performance liquid chromatography (HPLC) for detection of monoamine neurotransmitters and its metabolites after pre-column derivatization with dansyl chloride.

METHODSThe C(18) chromatograph column (150 mm×4.6 mm×5 µm) was selected for detection, and derived by dansyl chloride (10 mg/ml) under the condition of 50°C water bath by pH11 buffer solution. 20 µl acetic acid acetone solution (1.0 mol/L) was then mixed in for termination of the reaction. Then the solution was cooling to room temperature, 0.1 mol/L acetic acid zinc-acetonitrile-tetrahydrofuran solution was adopted for mobile phrase, with the volume ratio at 62:35:3. The flow rate was 1.0 ml/min between 0-10 min, 2.0 ml/min between 10-35 min. The ultraviolet detection wavelength was 286 nm. The above method separately detected monoamine neurotransmitters and its metabolites and evaluated the limit of detection, accurate degree and accuracy degree.

RESULTSThe linear relations between each component was good in the range of 1 - 20 µg/ml (r = 0.999). The lowest detection limit of norepinephrine, dopamine, 5-hydroxytryptamine and the metabolites 3-methoxy-4-benzoglycols, homovanillic acid and 5-heteroauxin were separately 0.60, 0.80, 0.41, 0.21, 0.19 and 0.1 µg/ml; while the average recovery rates were between 78.5% - 95.9%, and the relative standard deviation (RSD) was 6.62%, 7.64%, 2.98%, 3.60%, 5.09% and 3.09%, respectively. In the process of selection and optimization of the chromatographic conditions, we observed the importance of metal ions to discretion, and discussed the temperature, pH of the buffer solution and dosage of dansyl chloride in derivation. Under the above conditions, the reaction was perfect, and the baseline of the detected materials thoroughly separated.

CONCLUSIONThe method to detect monoamine neurotransmitters and its metabolites by HPLC and pre-column derivatization with dansyl chloride was established; and this method could provide reference for the detection of polyamine by HPLC.

Biogenic Monoamines ; analysis ; metabolism ; Chromatography, High Pressure Liquid ; methods ; Dansyl Compounds ; Neurotransmitter Agents ; analysis ; metabolism

Bone remodeling requires a large amount of energy, and is regulated by various hormones. Leptin, produced by adipocytes, is a well-known regulator of energy balance and is also involved in controlling bone mass through interaction with the central nervous system. Serotonin, downstream of leptin, is also emerging as a candidate for controlling energy balance and bone metabolism. Currently, bone is also considered to be an endocrine regulator of energy metabolism. Osteocalcin, secreted from osteoblasts, is known to be a key regulator of glucose and fat metabolism. In this review, we describe a novel concept that asserts that there exists a biological link between bone and energy metabolism, and we summarize what is currently known about the relationship between bone and energy metabolism.
Adipocytes ; Bone Remodeling ; Central Nervous System ; Energy Metabolism* ; Glucose ; Leptin ; Metabolism ; Neurotransmitter Agents ; Osteoblasts ; Osteocalcin ; Serotonin

Astrocytes can regulate synaptic transmission by releasing gliotransmitter, and also can promote synaptogenesis and neurogenesis by releasing estrogen, thrombospondins, IL-1beta and IL-6. Astrocytes may play critical roles in neural nutrition and neuroprotection, so that it might be a new target for treatment of certain central nervous system diseases.
Astrocytes ; physiology ; Estrogens ; metabolism ; Humans ; Interleukin-1beta ; metabolism ; Neurogenesis ; physiology ; Neurons ; physiology ; Neurotransmitter Agents ; metabolism ; Synaptic Transmission ; physiology ; Thrombospondins ; metabolism

OBJECTIVETo summarize 4 schools of thought in studies of meridians.

METHODSConsult literature and review the history of studies of meridians.

RESULTSThe studies of meridians in the past dozens years at home and abroad have gradually formed four main theories, namely the nerve-conduction meridian theory of neurophysiology, body fluid circulation meridian theory of the physio-biochemistry, bio-field meridian theory of biophysics, and the connective tissue structure meridian theory of the overall-gap viewpoint, which are summarized and analyzed.

Acupuncture Points ; Calcium ; metabolism ; Giant Cells ; physiology ; Humans ; Magnetics ; Meridians ; Neural Conduction ; Neurotransmitter Agents ; physiology

Propagated sensation along meridians (PSM) is a phenomenon that a sensation moves along meridians during stimulation of an acupoint. PSM has an appearance rate of 1.3% among people and have characteristics of low speed, going toward afflicted sites and being blocked by physical pressure which is difficult to be explained by known neural and blood transmission. Volume transmission (VT) is a widespread mode of intercellular communication in the central nervous system that occurs in the extracellular fluid and in the cerebrospinal fluid. VT signals moves from source to target cells via energy gradients leading to diffusion and convection (flow) which is slow, long distance and much less space filling. VT channel diffuse forming a plexus in the extracellular space with two parameters of volume fraction and tortuosity. Some experiments showed an information transmission between adjacent and distant acupoints along meridians cross spinal segments. This process is a cross-excitation between peripheral nerve terminals which is related to nonsynaptic transmission. Some neurotransmitters or neuropeptides such as glutamate, adenosine triphosphate (ATP) and neuropeptide such as substance P, neurokinin A and calcitonin gene-related peptide relate with the cross-excitation which can be regards as VT signals. Comparing the characteristics of PSM and VT, many similar aspects can be found leading to an assumption that PSM is a process of VT in peripheral tissue along meridians. The reason why VT signals transmit along meridians is that the meridian is rich in interstitial fluid under the condition of low hydraulic resistance which has been proven experimentally. According to Darcy's law which descript the flow of interstitial fluid and conservation equation, interstitial fluid will move toward meridians and flow along meridians that restrict the VT signals within the channel and accelerate the flow according to Fick's diffusion law. During the process, a degranulation of histamine from mast cells happens on the route which can expand capillary and increase the blood perfusion and interstitial fluid which had already been observed. The mechanism of PSM is featured by alternative axon reflex (wired transmission, WT) and VT in peripheral tissue along meridians, sending simultaneously a continuous sensate signal to control nerve system which can be felt like a PSM.
Cell Communication ; Humans ; Meridians ; Neurotransmitter Agents ; metabolism ; Organ Specificity ; Sensation ; physiology