Neuromuscular activity

Acetylcholine Nerve transmission (neuromuscular activates cation channels... 

Curare was first brought to the attention of Queen Elizabeth of England by Sir Walter Raleigh. The remarkable ability of the drug to induce paralysis of the muscles led to its early use by Claude Bernard, Kolliker, Langley, and subsequent physiologists to study the mechanism of neuromuscular activity. However, the uncertain supplies of the drug, its variability, and the effects of its contaminants prevented its therapeutic application. 

Hoppe JO (1955) Observations on the potency of neuromuscular blocking agents with particular reference to succinyl-choline. Anesthesiology 16 91-124 Cullen LK, Jones RS, Snowdon DL (1980) Neuromuscular activity in the intact dog Techniques for recording evoked mechanical responses. Br Vet J 136 154-159 Keesey JC (1989) AAEE Minimonograph 33 Electrodiagnosis approach to defects of neuromuscular transmission. Muscle Nerve 12 613-626... 

Maeda, M., Kodama, T, Tanaka, T, Ohfune, Y, Nomoto, K., Nishimura, K., and Fujita, T. 1984. Insecticidal and neuromuscular activities of domoic acid and its related compounds. J Pesticide Sci 9, 27-32. 

Magnesium is distinguished by the fact that it is required by most ATP-using enzymes. Here, Mg occurs as a complex with ATP, as shown in Figure 10,49. In other words, the true substrate for most ATF-requiring enzymes is not ATP, but the Mg-ATP complex. A deficiency in magnesium is uncommon. When it does occur, the physiological funchon that is most sensitive is neuromuscular activity. In molecular terms, the enzymes involved in neuromuscular activity that appear to be sensitive to Mg deficiency are those involved in the transport of sodium, potassium, and calcium, these enzymes are Na.K-ATPase and the calcium pump (Ca-ATPase). 

Exposure should be terminated as soon as possible either by removal of the patient or by fitting the patient with a gas mask if the atmosphere remains contaminated. Contaminated clothing should be removed immediately the skin and mouth should be washed with copious amounts of water. Gastric lavage should be conducted if necessary. Artificial respiration should be administered if required, and administration of oxygen may be necessary. If the convulsion persists, diazepam (5-10 mg intravenously) or sodium thiopental (2.5% intravenously) should be administered, and the patient should be treated for shock. Atropine should be administered in sufficiently large doses, but atropine is without any effect against peripheral neuromuscular activation and subsequent paralysis. Pralidoxime (1 or 2 g infused intravenously) should be administered for all the peripheral effects. 

If the increase in pH is great enough, increased neuromuscular activity may be seen, and above pH 7.55, tetany may develop even in the presence of a normal serum total calcium concentration. The cause of the tetany is a decreased concentration of ionized calcium due to increased binding of calcium ions by protein (mainly albumin) and other anions. Measurement of CL status can be helpful, as causes of metabolic alkalosis fall into Cfr responsive, CL resistant, and exogenous base categories (Box 46-1 see also Figure 46-4). 

Piper guineense Schumach et Thonn West African black pepper, Ashanti pepper Piperaceae Neuromuscular activity, contraceptive, antiparasitic, aphrodisiac Abdominal disorders, chest complaints, used as an enema. Bronchitis, Headache, An1helmintic,Caries, diarrhea, hemorrhoids, antibiotic. Alkaloidal amide, 12, 16, 17... 

The role of cytoskeletal tubulins in the mode of action and mechanism of drug resistance to benzimidazoles has been reviewed by Lacey [111], who also supports the above hypothesis proposing a close relationship between tubulin-microtubules and other sites of the benzimidazole action. It is believed that inhibition of glucose uptake, fumarate-reductase activity or neuromuscular activity are dependent on inhibition of polymerisation of tubulins to microtubules by benzimidazoles. The inhibition of tubulins by benzimidazoles is so pronounced that it is postulated that even the hatching of eggs of H. controtus is a microtubule dependent process [240]. 

The maintenance of physiologic calcium concentrations in the intracellular and extracellular spaces is vital for the preservation and function of cell membranes propagation of neuromuscular activity regulation of endocrine and exocrine secretory functions blood coagulation cascade platelet adhesion process bone metabolism muscle cell excitation/contraction coupling and mediation of the elec-trophysiologic slow-channel response in cardiac and smooth-muscle tissue. 

Magnesium is involved with many neuromuscular activities and cellular pathways that may affect PMS. Low intracellular magnesium levels have been reported in women with PMS compared with controls. It has been suggested that PMS may be related to an increased serum calcium-to-magnesium ratio. Daily or luteal magnesium supplementation of 200-360 mg/day was reported to be minimally helpful in reducing premenstrual fluid retention in women with PMS. A daily supplementation of 200 mg magnesium and 50 mg pyridoxine was found to reduce anxiety-related premenstrual symptoms in women with PMS compared with placebo. ... 

Parasitic helminths exhibit a variety of putative intercellular signalling molecules. These include classical small molecule transmitters, modulators and neuropeptides. In many cases there is close spatial association of cell bodies or neurites containing certain signaling molecules with muscle tissue or with motoneurons. This provides circumstantial evidence that these chemicals represent putative transmitters or modulators involved in neuromuscular activity. In other cases physiological experiments have directly demonstrated biological activity on muscle or motoneurons. 

We propose that conditions that inhibit neuromuscular activity also relieve feedback inhibition on IGF-II gene expression in muscle, and rat or human IGF-II mRNA content can be expected to increase. A prediction of this hypothesis is that sprouting will occur in response to nerve block with tetrodotoxin, or pre- and postsynaptic blocks with botulinum toxin or a-bungarotoxin, respec-... 

Polyneuronal innervation is lost during the first 2 weeks of life (Brown et al., 1976 O Brien et al., 1978). There is a 100-fold increase in miniature end-plate potentials between the first and second postnatal week of life (Diamond and Miledi, 1962 Nakajima et al., 1980). This coincides very closely with the postnatal decline in IGF-II gene expression. It is postulated that the increased neuromuscular activity (miniature end-plate potentials), through heightened feedback inhibition, causes down-regulation of IGF-II gene expression. The decline in IGF-II activity results in an environment that can no longer support multiple synapses and polyneuronal innervation is lost. 

This cation is essential for many enzyme reactions, neuromuscular activity, and bone formation it is the second most abundant intracellular cation. When compared... 

In support of these observations on alterations in neuromuscular activity, experiments were conducted on lobsters using 20E injections. Bolingbroke and Kass-Simon (2001) observed that intermolt females injected with 20E displayed increased aggressiveness relative to saline-injected controls. These experiments on the effects of ecdysteroids on crustacean behavior are especially relevant to the discussion of these hormones as possible pheromones and allelochemicals later in this chapter. 

A man admitted to hospital for an appendectomy became apnoeic during the early part of the operation when given suxamethonium (succinylcholine) 100 mg to facilitate tracheal intubation, and remained so throughout the 40 minutes of surgery. Restoration of neuromuscular activity occurred about 180 minutes after he had received the suxamethonium. Later studies showed that he had an extremely low plasma cholinesterase activity (3 to 10%), even though he had a normal phenotype. It subsequently turned out that he had been working with malathion for 11 weeks without any protection. ... 

Like calcium, magnesium is involved in numerous functions in living organisms concerning the activity of different enzymes as well as the neuromuscular activity. By this magnesium deficiency influences many biochemical processes followed by significant clinical symptoms, especially neuromuscular exutibility, heart dysrhythmia, and increased risk to cardiovascular... 

Magnesium is found primarily in the intracellular environment and is bound to adenosine triphosphate (ATP). Thus magnesium is important in almost all the body s metabolic functions. Elevated magnesium levels cause sedation and depressed neuromuscular activity, whereas low levels of magnesium cause neuromuscular excitabiUty. 

Because of the close dependence of neuromuscular activity on the concentration of calcium ions in the body fluids, it is essential that this level should be kept constant within very narrow limits. Control of phosphate ion concentration is also important, although rather larger variations can be tolerated for phosphate than for calcium. These levels are controlled mainly by the various dynamic relationships that exist between the dissolved ions in the extracellular fluids and the solid phosphates of bone (page 438). The very rapid exchange reaction involving a small labile reserve of calcium and phosphate ions is purely physicochemical in nature and consequently limited in scope, yet it enables the plasma calcium concentration to be rapidly adjusted, equilibrium being established in about 4 min. 

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