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^ N-type Calcium Channel
Wikipedia Voltage dependent calcium channel
^ NADH Nicotinamide adenine dinucleotide. A coenzyme found in all living cells involved as a redox agent in electron transfer reactions.
^ NADH dehydrogenase Complex I of the mitochondrial electron transport chain. Involved with Leber Hereditary Optic Neuropathy.
^ NARP Neurogenic muscle weakness, Ataxia, and Retinitis Pigmentosa. See Leigh syndrome
^ Necrosis Death of diseased cells near normal cells. As different from apoptosis
^ Nerve Growth Factor The love factor. A small protein stimulating nerve growth. One of first to be described.
Emanuele E, Politi P, Bianchi M, Minoretti P, Bertona M, Geroldi D. Raised plasma nerve growth factor levels associated with early-stage romantic love. Psychoneuroendocrinology. 2006 Apr;31(3):288-94. Epub 2005 Nov 10. PMID 16289361
^ Neurilemma or Neurolemma Outermost layer of nerve fibers in the peripheral nervous system myelinated by Schwann cells. Absent in the central nervous system including the optic nerve as oligodendrocytes myelinate these nerve fibers.
^ Neuritis,Optic see Optic Neuritis.
^ Neurocysticercosis Tapeworm infection of the brain. The most common parasitic disease of the central nervous system. Prevalent in Mexico and Central and South America and other parts of the world. Epilepsy is common as well as various neurologic symptoms. Optic neuropathy may be present.
Roman G, Sotelo J, Del Brutto O, Flisser A, Dumas M, Wadia N, Botero D, Cruz M, Garcia H, de Bittencourt PR, Trelles L, Arriagada C, Lorenzana P, Nash TE, Spina-Franca A. A proposal to declare neurocysticercosis an international reportable disease.Bull World Health Organ 2000;78(3):399-406 PMID 10812740
Salinas R, Prasad K. Drugs for treating neurocysticercosis (tapeworm infection of the brain).Cochrane Database Syst Rev 2000;2:CD000215 PMID 10796510
^ Neuroglia Cells which surround neurons. See glia.
^ Neuromyelitis Optica (Devic's Disease) An autoimmune cause of optic neuritis.
^ Neuropathy Disease of nerves. Usually refers to peripheral nerves. See also optic neuropathy
^ Neuroprotection Saving nerves from apoptosis and degeneration. Studies in this area are key to preventing blindness from optic neuropathies.
Matthias Endres, Ulrich Dirnagl. Neuroprotective Strategies in Animal and in Vitro Models of Neuronal Damage: Ischemia and StrokeEurekah Bioscience Collection Neurodegenerative Disease
^ Neuroreceptor Binding site for neurotransmitters
^ Neurotransmitter A chemical effecting a signal between a neuron and another cell.
Helga Kolb. Neurotransmitters in the retina.
^ Neurotrophin A family of proteins, which induce the survival of neurons.
^ NT-4/5 (Neurotrophin-4 or 5)
^ Nerve Fibre Layer Inner most retinal layer where retinal ganglion cell axons course through the retina.
^ Nitric Oxide (NO·) A gaseous molecule with one oxygen atom (with six valence electrons) and one nitrogen atom (with five valence electrons). The Lewis electron structure, ·|N=O|| , shows a double bond is created with the atoms having an average of seven and a half electrons each, including the shared electrons in the double bond, rather than eight required for a stable noble gas. In other words there is an unpaired electron, symbolized by the middle dot ( · ), making this molecule a free radical. NO· is synthesized from l-arginine by different types of the enzyme nitric-oxide synthase (NOS) depending on location in the tissues. It freely diffuses through tissues and cells. The brain has the highest known tissue levels of NOS. NO· is known to have various functions in the body including endothelial relaxing factor (ERF), neurotransmission, NMDA neuroreceptor modulation and many other possible actions. It and its related species target various molecules both physiologically and pathologically. Enzymes, G proteins, transcription factors, transporters and ion channels are targets in neurons. It is produced in or modulates all neuron and glial cells in the eye. For example, it is known to down regulate retinal horizontal cell activity and thus prevent glutamate excitotoxicity. It shares some functions with another gas, carbon monoxide.
P Vallance, J Collier. Education and debate Fortnightly Review Biology and clinical relevance of nitric oxide BMJ 1994;309:453-7 (13 August)
Javier Cudeiro and Casto Rivadulla. Review Sight and insight - on the physiological role of nitric oxide in the visual system. Trends in Neurosciences. 1999, 22:109-116 PMID 10199635
^ Nitric oxide synthase
^ NMDA Receptor A type of ionotropic glutamate neuroreceptor (iGluR) found in the central nervous system. NMDA (N-Methyl- D-Aspartate) is the selective agonist differentiating it from non-NMDA iGluR's. It has complex modulation sites which include separate binding sites for glutamate, glycine, magnesium ions (Mg+2) which controls a voltage gated channel, zinc ions (Zn+2), a polyamine recognition site and nitric oxide binding. In humans and other primates these receptors are found in retinal ganglion cells.
^ NAION Non arteritic anterior ischaemic optic neuropathy See AION
^ Normotension Glaucoma (NTG) Glaucoma without raised intraocular pressure. There is evidence that this may be associated with chromosomal genetic mutations.
^ Nucleic Acids Linear polymers of nucleotides which encode genetic information. The basic examples are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). When broken down by hydrolysis they produce equal parts of nitrogenous bases, five carbon sugars (deoxyribose in DNA and ribose in RNA), and phosphoric acid. The nitrogenous bases are either purine or pyrimidine derivatives. The common purines, adenine (A) and guanine (G) are both found in DNA and RNA. The common pyrimidines, cytosine (C) and thymine (T) are found in DNA while cytosine and uracil (U) are in RNA. The order of the bases determine the genetic code. A row of three bases code for one amino acid, linear polymers of which form proteins.
^ Nucleoside A compound formed by linking a base to a sugar by a glycosidic bond. The common nucleosides are cytidine, uridine, thymidine, adenosine and guanosine.
^ Nucleotide Nucleotides are nucleoside phosphates. Most free nucleotides in the cell are ribonucleotides having a phosphoric acid esterified at the C-5 position hydroxyl of ribose. The names of the four common monomeric ribonucleotides(NMP's) are: adenosine 5'-monophosphate (5'-AMP or AMP), guanosine 5'-monophosphate (5'-GMP or GMP), cytidine 5'-monophosphate(5'-CMP or CMP) and uridine 5'-monophosphate (5'-UMP or UMP). Their deoxyribonucleotide (dNMP) counterparts are respectively dAMP,dGMP, dCMP, dUMP and dTMP. Cyclic nucleotides in the cell have their phosphoric acid esterified to two of the available ribose hydroxyl groups 3' and 5'. 3'-5'-cyclic AMP (cAMP) and 3'-5'- cyclic GMP (cGMP) are important regulators of metabolism. Nucleoside 5'-diphosphates (NDP's)(e.g. ADP, GDP, CDP and UDP)and nucleoside 5'- triphosphates (NTP's)(e.g. ATP, GTP, CTP and UTP) are progressively higher in energy. ATP is regarded as the major energy currency of the cell. GTP is the major energy source in protein synthesis. CTP is an essential metabolite in phospholipid synthesis. UTP is involved with intermediate steps in complex carbohydrate and polysaccharide synthesis. The four NTP's and their dNTP counterparts are the substrates for the formation of nucleic acids.
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