Nerve signal transduction

Alkali metal transport in biochemistry is a vital process in maintenance of cell membrane potentials of use, for example, in nerve signal transduction and is at the core of some of the early work on artificial ionophores that mimic natural ion carriers such as valinomycin. Ionophore mediated ion transport is much slower than transport through cation and anion ion channel proteins, however. 

The smooth muscle cell does not respond in an all-or-none manner, but instead its contractile state is a variable compromise between diverse regulatory influences. While a vertebrate skeletal muscle fiber is at complete rest unless activated by a motor nerve, regulation of the contractile activity of a smooth muscle cell is more complex. First, the smooth muscle cell typically receives input from many different kinds of nerve fibers. The various cell membrane receptors in turn activate different intracellular signal-transduction pathways which may affect (a) membrane channels, and hence, electrical activity (b) calcium storage or release or (c) the proteins of the contractile machinery. While each have their own biochemically specific ways, the actual mechanisms are for the most part known only in outline. 

The structural design of nerve cells is a striking example of dendritic architecture, which acts as a signal transduction system. Neurons are known to send out a series of long specialized processes that will either receive electrical signals (dendrites) or transmit these electrical signals (axons) to their target cells (Fig. 5.40). 

Neary JT Department of Veterans Affairs, Medical Center, Miami, FL Effects of lead on nerve growth factor-induced neurite outgrowth and branching due to an interaction of lead with signal transduction mechanisms important for neuronal differentiation Department of Veterans Affairs, Research and Development... 

Duman RS, Heninger GR, Nestler EJ Adaptations of receptor-coupled signal transduction pathways underlying stress- and drug-induced neural plasticity. J Nerv Ment Dis 182 692-700, 1994... 

Demyelination. The role of myelin in the nervous system is to aid in signal transduction. Myelin acts like an electrical insulator by preventing loss of ion current, and intact myelin is critical for the fast saltatory nerve conduction discussed above. Neurotoxicants that target the synthesis or integrity of PNS myelin may cause muscle weakness, poor coordination, and paralysis. In the brain, white matter tracts that connect neurons within and between hemispheres may be destroyed, in a syndrome known as toxic leukoencephalopathy. A multifocal distribution of brain lesions is reflected in mental deterioration, vision loss, speech disturbances, ataxia (inability to coordinate movements), and paralysis. 

Hayflick JS (2000) A family of heptahelical receptors with adhesion-like domains a marriage between two super families. J Recept Signal Transduct Res 20 119-31 Hlubek M, Tian D, Stuenkel EL (2003) Mechanism of a-latrotoxin action at nerve endings of neurohypophysis. Brain Res 992 30-42... 

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