Protein nerve impulse transmission

Nerve impulse transmission Some proteins behave as receptors of small molecules that pass between gaps (synapses) separating nerve cells. In this way, they transmit nerve impulses from one nerve to another. Rhodopsin, a protein found in the rod cells of the retina of the eye, functions this way in the vision process. 

The bacosides aid in repair of damaged neurons by enhancing kinase activity, neuronal synthesis, and restoration of synaptic activity. Ultimately, nerve impulse transmission is relived, and a boost in the synthesis of new proteins in the brain is also observed [1]. 

The mechanism of neurotoxin action on the nerve systems involves blocking of the nerve impulse transmission at the site of the neuromuscular junction by strong specific binding to the acetylcholine receptor in the postsynaptic membrane, thus interrupting the pathway whereby the neurotransmitter released in the synaptic cleft could affect the excitability of the postsynaptic neuron. The availability of highly purified acethylcholine receptor protein(24) allows a direct study of the structure-activity relationship of neurotoxins and their bindings with the receptor. 

As an activator of the phosphokinases, magnesium is essential in energy-requiring biological processes, such as activation of amino acids, acetate, and succinate synthesis of proteins, fats, coen2ymes, and nucleic acids generation and transmission of nerve impulses and muscle contraction (67). 

More than 99% of total body calcium is found in bone the remaining less than 1% is in the ECF and ICE Calcium plays a critical role in the transmission of nerve impulses, skeletal muscle contraction, myocardial contractions, maintenance of normal cellular permeability, and the formation of bones and teeth. There is a reciprocal relationship between the serum calcium concentration (normally 8.6 to 10.2 mg/dL [2.15 to 2.55 mmol/L]) and the serum phosphate concentration that is regulated by a complex interaction between parathyroid hormone, vitamin D, and calcitonin. About one-half of the serum calcium is bound to plasma proteins the other half is free ionized calcium. Given that the serum calcium has significant protein binding, the serum calcium concentration must be corrected in patients who have low albumin concentrations (the major serum protein). The most commonly used formula adds 0.8 mg/dL (0.2 mmol/L) of calcium for each gram of albumin deficiency as follows ... 

Oxidative phosphorylation is central to the metabolism of all higher organisms, because the free energy of hydrolysis of the ATP so generated is used in the synthesis of, inter alia, nucleic acids (Chaps. 7 and 16), proteins (Chaps. 4,9, and 17), and complex lipids (Chap. 6), as well as in processes as diverse as muscle contraction (Chap. 5) and the transmission of nerve impulses. 

The complexing of calcium by EDTA and also by polyphosphates is of importance, not only for removal of calcium ions from water, but also for the volumetric estimation of calcium. In Ca[CaEDTA]-7H20 the coordination of the Ca ion is 8. Calcium ions are involved in many natural processes such as bones (Ca5(P04)30H), blood clotting, transmission of nerve impulses, and so on as well as in selective binding to various proteins with a range of functions. 

FIGURE 6.10 The neuromuscular junction. The region of contact between one nerve and another nerve, or between a nerve and a muscle cell, is called a s)maptic cleft. The secretory vesicles are represented by circles in which acetylcholine is represented by dots. The nerve impulse provokes the entry of calcium ions (not shown) from the extracellular fluid into the nerve cell. Calcium ions act as a signal that stimulates the fusion of vesicles with the plcisma membrane, releasing acetylcholine into the extracellular fluid. Acetylcholine binds to membrane-bound proteins (acetylcholine receptors) on the plasma membrane of the muscle cell, resulting in stimulation of the muscle cell. Acetylcholinesterase of the neuromuscular junction catalyzes the destruction of acetylcholine in the moments after transmission of the nerve impulse. The enzyme is extracellular and is bound to proteoglycan, a molecule of extracellular matrix. 

Scorpion venom is composed of many different fractions that can vary among the different scorpion species. These venom fractions act at different tissue receptor sites. Local tissue reaction is a result of the inflammatory response to the injected foreign proteins and enzymes making up the venom. The venom of Centruroides species contains several different neurotoxins. These toxins block the transmission of nerve impulses in the central nervous system and in muscles by blocking the transport of ions through sodium and potassium channels at the cellular level. Other venom components may decrease the heart rate by causing the release of acetylcholine. 

Sodium comprises -90% of the cations present in plasma. By contrast, the normal intracellular sodium concentration is generated and controlled by various types of channel proteins such as Na" ", K" "-ATPase and Na -glucose cotransporters inserted into the cell membrane, and these play an important role in the transmission of nerve impulses and translocation of biorelated substances across the cell membrane. The normal sodium ion concentrations in body fluids are listed in Table 1.2-12. 

Myelin is a multilayer sheath consisting mainly of lipids (with some proteins) that insulates the axons of nerve cells, facilitating transmission of nerve impulses. 

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