Nerve cell parts

Cholinergic transmission, but nerve cell chain originates in the thoracolumbar part of the spinal cord and is therefore sympathetic, alpha, a beta, 3. 

Raff But at least you know that you are talking about a particular part of the cycle. It would be nice to have terminology that distinguishes permanent withdrawal from the cell cycle, as in a nerve cell, from transient withdrawal, as in a lymphocyte. 

Smoke now drifts down and spreads, gradually creating a uniform fog. Sufentanil alone might not be visible, but it is part of an aerosol made up of billions of very small dmg-impregnated particles. Without additional material to piggyback them, even distribution of the sufentanil molecules would be impossible. It s a fine science. Only in a size range of one to five microns - less than a tenth the diameter of a human nerve cell - will the particles reach the lower lungs, and stay there. 

Langley JN (1901) On the stimulation and paralysis of nerve-cells and of nerve-endings. Part I. 

Neurotransmission. This is the most important part of nervous system function for us to understand, both because it serves as the cornerstone of nerve cell signaling, and because it is the process that is modulated by psychotropic medications and... 

The newest appetite suppressant, sibutramine (Meridia), works by blocking the reuptake of both serotonin and norepinephrine. It does not stimulate nerve cells to release serotonin, as do fenfluramine and dexfenfluramine. Administered at 20 mg/ day, sibutramine effectively reduces weight in obese patients, but its use has not been assessed in eating disorder patients. The most common side effects of this medication are insomnia, dry mouth, and constipation. It has not been associated with the more serious heart and lung complications observed with fenfluramine and dexfenfluramine. Because sibutramine acts in part through modulation of norepinephrine, there is no rational basis for coadministering phentermine, which acts via this same mechanism. 

Dopamine activity can be enhanced in one of four main ways. Medications can stimulate dopaminergic nerve cells to release dopamine into the synapse. This is the way that stimulants such as methylphenidate (Ritalin), dextroamphetamine (Dexe-drine), and dextroamphetamine/amphetamine (Adderall) work. In addition, certain drugs of abuse, notably cocaine and methamphetamine, act in part in this way. Providing more of the raw material that nerve cells use to manufacture dopamine can also increase dopamine activity. This is the approach that neurologists use when they prescribe L-DOPA (Sinemet) to patients with Parkinson s disease. Nerve cells convert L-DOPA into dopamine. L-DOPA otherwise has little place in the treatment of psychiatric disorders. Dopamine activity can also be increased by medications that directly stimulate dopamine receptors. Bromocriptine, another medication used to... 

Generally, it is always only a very small part of the membrane that is depolarized during an action potential. The process can therefore be repeated again after a short refractory period, when the nerve cell is stimulated again. Conduction of the action potential on the surface of the nerve cell is based on the fact that the local increase in the membrane potential causes neighboring voltage-gated ion channels to open, so that the membrane stimulation spreads over the whole cell in the form of a depolarization wave. 

Synapses are the contact points of two nerve cells or of a nerve cell with an effector cell (such as a muscle, glandular or sensory cell). It is at the synapse, exactly at the synaptic cleft, where the transfer of information from one cell to the next takes place. It is estimated that the diameter of a synaptic cleft, Le. the distance between the presynaptic membrane (part of the first cell) and the postsvnaptic membrane (part of the second cell), is about 100 300 pm. Depending on the carrier of information, electrical and chemical synapses can be distinguished ... 

The nicotinic acetylcholine receptor is a protein of 290 kD that occins in chemical synapses where conummication between nerve cells and muscle cells takes place. Binding of acetylcholine to the receptor induces opening of the ion chaimel, which is a part of the receptor. Passage of Na and ions through the receptor takes place and depolarization of the postsynaptic cell occurs. The depolarization represents a signal that-according to the nature of the postsynaptic cell—is processed in various ways. 

Isolated microtubules always contain small amounts of larger 300-kDa microtubule-associated proteins (MAPS).330 These elongated molecules may in part lie in the grooves between the tubulin subunits and in part be extended outward to form a low-density layer around the tubule.283 309 Nerve cells that contain stable microtubules have associated stabilizing proteins.331 A family of proteins formed by differential splicing of mRNA are known as tau. The tau proteins are prominent components of the cytoskeleton of neurons. They not only interact with microtubules but also undergo reversible phosphorylation. Hyperphosphorylated tau is the primary component of the paired helical filaments found in the brains of persons with Alzheimer disease.330... 

CHOLINE AND CHOLINESTERASE. An enzyme iucetylchnlinesie rase I is specific for the hy droly sis of acetylcholine to acetic ueid and choline in the animal body. It is found in the brain, nerve cells and red blood cells and is important in the mechanism of nerve action. Acetylcholine w as first synthesized in 1867. It consists of a combination of chnlinc and acetic acid in an ester linkage. The component parts til the acetylcholine molecule are both normal constituents nf the animal body. Acetylcholine has the structure ... 

We may now assemble the foregoing information into a molecular description of a few biological processes in which the interaction between water and metal ions plays an important role. First some problems related to signal transfer in nerve cells are discussed. This is followed by some comments on the mechanism operating at nerve synapses in which, in addition to the sodium and potassium ions, a specific transmitter substance and calcium ions take part. 

Similarly, apolipoprotein E expression increases in neurotoxicity mediated by KA (Table 6.3) (Boschert et al., 1999). Apolipoprotein E is a major lipoprotein in the brain. It is involved in the transport, distribution, and other aspects of cholesterol homeostasis. Apolipoprotein E also plays a dominant role in the mobilization and redistribution of brain lipids in repair, growth, and maintenance of nerve cells (Mahley, 1988). The secretion of apolipoproteins E and D may be differentially regulated in cultured astrocytes. In cell culture systems this depends upon the extracellular lipid milieu (Patel et al., 1995). During neurotoxicity mediated by KA, apolipoprotein E levels increase moderately in astrocytes and apolipoprotein E mRNA increases very strongly in clusters of CA1 and CA3 pyramidal neurons. Based on hybridization in situ and immunohistochemical studies, expression of apolipoprotein E in neurons may be a part of a rescue program to counteract neurodegeneration mediated by KA (Boschert et al., 1999). 

RECEPTOR A specialized part of a nerve cell that recognizes neurotransmitters and communicates with other nerve cells. 

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