Torpedo, electric organ

Viewing things from the perspective of his physical theory of contact electricity, Volta was intrigued by the apparently endless power of the battery to keep the electric fluid in motion without the mechanical actions needed to operate the classical, friction, electrostatic machine, and the electrophorus. He called his batteiy alternately the artificial electric organ, in homage to the torpedo fish that had supplied the idea, and the electromotive apparatus, alluding to the perpetual motion (his words) of the electric fluid achieved by the machine. To explain that motion Volta relied, rather than on the concepts of energy available around 1800, on his own notion of electric tension. He occasionally defined tension as the effort each point of an electrified body makes to get rid of its electricity but above all he confidently and consistently measured it with the electrometer. 

The acetylcholine receptor (AChR) of Torpedo electric organ is also a PCP "receptor." However, this nicotinic AChR has about one-tenth the affinity for PCP than that of the rat brain PCP receptor [K0.5 = 0.3 pM, versus = 4-6 pM for Torpedo (Heidmann et al. 1983 flaring et al. 1984)]. Moreover, the nicotinic AChR has subunits of MR<66 kD, and these are the subunits that are specifically labelled with 3H-Az-PCP in the Torpedo electroplax membranes (Heidmann et al. 1983 Haring and Kloog 1984 Haring et al. 1984). These data indicate that the nicotinic AChR-PCP receptor differs from the rat brain PCP receptor. Furthermore, our findings are... 

Haring, R., and Kloog, Y. Multiple binding sites for phencyclidine on the nicotinic acetylcholine receptor from Torpedo ocel -lata electric organ. I ife Sci 34 1047-1055, 1984. 

Caenorhabditis elegans is a soil nematode that has been subjected to detailed genetic analysis. The possible structure of the nematode levamisole receptor, based on the pentameric structure of the nicotinic channel of the Torpedo electric organ (Devillers-Thiery et al, 1993), is shown in Fig. 21.12. 

Van der Kloot, W. Loading and recycling of synaptic vesicles in the Torpedo electric organ and the vertebrate neuromuscular junction. Prog. Neurobiol. 71, 269-303, 2003. 

Sadoulet-Puccio, H. M., Khurana, T. S., Cohen, J. B., and Kundel, L. M. (1996). Cloning and characterization of the human homologue of a dystrophin related phosphopro-tein found at the Torpedo electric organ post-synaptic membrane. Hum. Mol. Genet. 4, 44489-44496. 

Frozen electric organ from Torpedo californica (Aquatic Research Organisms, Inc., Hampton, NH) Maintain at -80°C. 

Determination of nAChR-Binding Sites in Torpedo Electric Organ Membrane Preparations... 

To perform in vitro transcription reaction Save 20 pi of the total volume of 100 pi (for P-UTP transcription for binding studies with uAChRs in Torpedo electric organ membranes, and in case you have to amplify the DNA again) and use 80 pi for transcription. 

The isolation of the nicotinic acetylcholine receptor glycoprotein was achieved almost simultaneously in several laboratories (those of Changeux, O Brien, Brady, and Eldefrawi) and was helped tremendously by the discovery that the electric organ (elec-troplax) of the electric eel (Electrophorus electricus, an inhabitant of the Amazon River) and related species, as well as the electroplax of the electric ray Torpedo tnar-morata) of the Atlantic Ocean and the Mediterranean Sea, contains acetylcholine receptors (AChR) in a much higher concentration than, for instance, in human neuromuscular endplates or brain tissue. 

Torpedo electric organ. Compared to normal concentration standards, this yield is exceptionally high. 

Fig. 16.13. Pore structure of the acetylcholine receptor, based on electron microscopy studies. a) Electron density map of the acetylcholine receptor of the postsynaptic membrane of the electric organ of the ray Torpedo californicus, based on electron microscopy studies. The receptor has a long funnel-like structure in the extracellular region, which narrows at the center of the pore. A smaller funnel structure is observed in the cytoplasmic region of the receptor. Another protein is situated on the cytoplasmic side. The long arrow indicates the direction of ion passage and the small arrow shows the postulated binding site for acetylcholine, b) Schematic representation of the acetylcholine receptor with the M2 hehx as the central block in the ion channel. According to Unwin, (1993).

Pentameric structure in Torpedo electric organ and fetal mammalian muscle has two G.1 subunits and one each of Bl, 5, and 7 subunits. The stoichiometry is indicated by subscripts, eg, [(ct-l)2 Bl 5 7]. In adult muscle, the 7 subunit is replaced by an ... 

True Cholinesterase from the Electric Organs of Eleclrophorus electricus or Torpedo marmorata... 

Anderson DC, King SC, Parsons SM (1983) Pharmacological characterization of the acetylcholine transport system in purified Torpedo electric organ synaptic vesicles. Mol Pharmacol 24 48-54. 

Use of Toxin Binding to Purify a Channel Protein a-Bungarotoxin is a powerful neurotoxin found in the venom of a poisonous snake (Bungarus multicinctus). It binds with high specificity to the nicotinic acetylcholine receptor (AChR) protein and prevents the ion channel from opening. This interaction was used to purify AChR from the electric organ of torpedo fish. 

Acetylcholine receptor from electric organ of Torpedo sp. Receptor protein noncovalently bound on the surface of a planar interdigitated capacitative sensor. Response was concentration dependent and specific for ACh and inhibited by (+ )-tubocurarine, amantidine and a-neurotoxin. [66]... 

Israel and Lesbats reported a chemiluminescence method for the determination of acetylcholine, and continuous detection of its release from torpedo electric organ synapses and synaptosomes [55], Birman described a new chemiluminescence assay method for the determination of acetylcholineesterase activity with the natural substrate [56], The method involved monitoring the increase in light emission produced by accumulation of choline, or measuring the amount of choline generated. 

Volta pile — On March 20, 1800, Alessandro - Volta, then professor of the University of Pavia sent a letter in French from Como, Lombardy to Sir Joseph Banks (1743-1820) the president of the Royal Society of London, for publication. He described a device - that he called artificial electrical organ referring to the natural electrical organ of the torpedo or electric eel - producing perpetual electrical motion. The paper was read at the Society on 26 June and published in the September issue of the Philosophical Transactions. The whole paper appeared in English in the Philosophical Magazine the same year [i, ii]. 

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