Paralytic effects

Curative treatment involves counteracting the paralytic effect of the Ba " ion on the muscle by intravenous infusion of a potassium salt. 

Tetanus antitoxin Neutralization of the paralytic effect of tetanus toxin in mice 1000 lU ml for prophylaxis 3000 lU ml for treatment... 

Acidic methanolic extracts of larvae of Tenebrio molitor contain toxic substances, so-called paralysins, which exhibit immediate paralytic effects on other insects upon injection [336]. 

Homatropine is a synthetic parasympatholytic representing the ester of tropine and mandelic add (Fig. 1). This drug antagonizes acetylcholine on MR and is thus used as mydriatic with less detrimental paralytic effects on ciliary eye muscle than atropine but showing faster and shorter action [1,33], Therefore, it belongs to the WHO list of essential medicines as mydriatic eye drops representing an alternative to atropine [41],... 

The form with which most of the public is familiar is foodborne botulism. There are approximately 30 cases of foodborne botulism reported in the United States each year, most of which are related to home processing of foods. The botulinum toxin produced by C. botulinum is actually a group of distinct toxins with similar paralytic effects on the neurologic system. Botulinum toxin is the most poisonous substance known to mankind less than one microgram is a fatal dose for an adult (Arnon et al., 2001). 

Once translocated into the cytosol, the toxic fragments exert their paralytic effects by inhibiting ACh release from neuromuscular junctions as well as other peripheral cholinergic sites, including sympathetic and parasympathetic ganglia and post-ganglionic parasympathetic synapses (Lamanna, 1959 Vincenzi, 1967 Simpson, 2004). 

These paralytic effects have been attributed to the proteolytic activity of BoNT light chain (LC) on protein substrates required for vesicular exocytosis. BoNT LC inhibits neurotransmitter exocytosis through its zinc-dependent endoproteolytic activity. The LCs of the various neurotoxin serotypes possess distinct molecular targets within the peripheral cholinergic nerve termainals (Schiavo et al, 1992, 1993a, b, 1994, 1995 Yamasaki et al, 1994). The endoproteolytic activities of the different toxin LCs produce similar flaccid paralytic effects. 

Praziquantel stimulates the movement of Hymenolepis and Echinococcus spp. at low concentrations (1 ng/ ml). Higher concentrations of the drug causes rapid contraction of the worms. At a concentration of 1-10 pg/ml of praziquantel, the helminths were found to be immobilized and contracted within 10-30 seconds [26,122,123]. The tetanic contraction of the worm s musculature results in its paralysis. Fetterer and coworkers [124] have shown that the drug is capable of inducing spastic and/or paralytic effects in cestodes, trematodes and to some extent in nematodes also. 

A large number of toxic peptides are found in cone snails (Conidae). They include four classes of small (13-29 amino acid) basic peptides, known as conotoxins, that have paralytic effects cu-conotoxins block presynaptic calcium channels, a-conotoxins bind to nicotinic ACh receptors in muscle, p-contoxins bind to muscle sodium channels, K-conotoxins may affect potassium channels. Other cone snail toxins include sleeper that induces sleep in mice, conopressin that produces scratching behaviour in mice and increases blood pressure in mammals and a larger (ca. 100 amino acid) toxin that produces convulsions in mice. 

Horseshoe crabs use defense tactics in reproduction. They, like other organisms, take in some chemicals with their diet but the status of bioactive metabolites is not known. Also daddy longlegs have chemical defense using a lot of chemical compounds, including alkaloids. Scorpion biotoxins (e.g., bot-ulinum) are the most toxic compounds known. They effect neuromuscular paralytic effects. Botulinum is a neurotoxic protein, very dangerous. Scorpions probably also have alkaloids, although their role is yet to be researched. 

Pharmacological studies of curare were initiated in the middle of the nineteenth century by the French physiologist Claude Bernard (1813— 1878). The dominant pharmacological effect of curare is the paralysis of the whole skeletal muscle in both warm- and cold-blooded animals. The sequence of the paralytic effects of the skeletal muscle is well defined. At first, the eyes, ears, and toes are affected, and next the muscles of the arms and legs. Paralysis of the muscles of the neck then occurs, and finally the respiratory muscles are affected, resulting in suffocation in warm-blooded animals. The muscle relaxant activity of curare is strengthened by diethylether. Because curare can release stored histamine in the tissues, it may cause hypotension and excessive secretion in the trachea. 

Numerous bisindole alkaloids, formed by dimerization of monomeric monoterpenoid-derived indoles, have been isolated. Probably the best source of these alkaloids is Cathara-nthus roseus bisindole alkaloids from this source have been tabulated (Blasko and Cordell, 1990). Several of these alkaloids antitumor activity (Blasko and Cordell, 1988) most important in this regard are vincristine (55) and vinblastine (56) from Catharanthus roseus (Fig. 34.15). Certain other dimeric indole alkaloids known as curares have paralytic effects in animals (see the subsection Curares from Strychnos species, above). 

Saxitoxins are selective, reversible, voltage-gated sodium channel blockers (Huot et al., 1989 Tarnawa et al., 2007 Walker et al., 2013). Saxitoxins cross the blood-brain barrier, and sodium channel blockade in the CNS contributes to its paralytic effects (Borison and McCarthy, 1977). Saxitoxins are extremely potent, with mouse LD50 values of 263pg/kg (oral), lOpg/kg (intraperitoneal), and 3.4pg/kg (intravenous) (Wiberg and Stephenson, 1960). 

American product caused a paralytic effect of 1.2, while 0.6 lethal units of the British product caused a paralytic effect of 1.07. 

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