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Marine Origin Ligands of Nicotinic Receptors: Low Molecular Compounds, Peptides and Proteins for Fundamental Research and Practical Applications. Biomolecules 2022; 12:biom12020189. [PMID: 35204690 PMCID: PMC8961598 DOI: 10.3390/biom12020189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/05/2023] Open
Abstract
The purpose of our review is to briefly show what different compounds of marine origin, from low molecular weight ones to peptides and proteins, offer for understanding the structure and mechanism of action of nicotinic acetylcholine receptors (nAChRs) and for finding novel drugs to combat the diseases where nAChRs may be involved. The importance of the mentioned classes of ligands has changed with time; a protein from the marine snake venom was the first excellent tool to characterize the muscle-type nAChRs from the electric ray, while at present, muscle and α7 receptors are labeled with the radioactive or fluorescent derivatives prepared from α-bungarotoxin isolated from the many-banded krait. The most sophisticated instruments to distinguish muscle from neuronal nAChRs, and especially distinct subtypes within the latter, are α-conotoxins. Such information is crucial for fundamental studies on the nAChR revealing the properties of their orthosteric and allosteric binding sites and mechanisms of the channel opening and closure. Similar data are provided by low-molecular weight compounds of marine origin, but here the main purpose is drug design. In our review we tried to show what has been obtained in the last decade when the listed classes of compounds were used in the nAChR research, applying computer modeling, synthetic analogues and receptor mutants, X-ray and electron-microscopy analyses of complexes with the nAChRs, and their models which are acetylcholine-binding proteins and heterologously-expressed ligand-binding domains.
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Ji PY, Zhang MZ, Xu JW, Liu YF, Guo CC. Transition-Metal-Free TBAI-Facilitated Addition–Cyclization of N-Methyl-N-arylacrylamides with Arylaldehydes or Benzenesulfonohydrazides: Access to Carbonyl- and Sulfone-Containing N-Methyloxindoles. J Org Chem 2016; 81:5181-9. [DOI: 10.1021/acs.joc.6b00773] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Peng-Yi Ji
- College
of Chemistry and
Chemical Engineering, Advanced Catalytic Engineering Research Center
of the Ministry of Education, Hunan University, Changsha 410082, China
| | - Ming-Zhong Zhang
- College
of Chemistry and
Chemical Engineering, Advanced Catalytic Engineering Research Center
of the Ministry of Education, Hunan University, Changsha 410082, China
| | - Jing-Wen Xu
- College
of Chemistry and
Chemical Engineering, Advanced Catalytic Engineering Research Center
of the Ministry of Education, Hunan University, Changsha 410082, China
| | - Yu-Feng Liu
- College
of Chemistry and
Chemical Engineering, Advanced Catalytic Engineering Research Center
of the Ministry of Education, Hunan University, Changsha 410082, China
| | - Can-Cheng Guo
- College
of Chemistry and
Chemical Engineering, Advanced Catalytic Engineering Research Center
of the Ministry of Education, Hunan University, Changsha 410082, China
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Liu XL, Pan BW, Zhang WH, Yang C, Yang J, Shi Y, Feng TT, Zhou Y, Yuan WC. A highly efficient and eco-friendly method for the synthesis of 1,3-indandione ring-fused 3-oxindoles bearing two contiguous quaternary stereocenters via an aldol reaction in aqueous media. Org Biomol Chem 2015; 13:601-11. [DOI: 10.1039/c4ob02103g] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and antitumor activity evaluation of 1,3-indandione ring-fused 3-oxindoles.
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Affiliation(s)
- Xiong-Li Liu
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Bo-Wen Pan
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Wen-Hui Zhang
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Chao Yang
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Jun Yang
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Yang Shi
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Ting-Ting Feng
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Ying Zhou
- Guizhou Engineering Center for Innovative Traditional Chinese Medicine and Ethnic Medicine
- College of Pharmacy
- Guizhou University
- Guiyang
- China
| | - Wei-Cheng Yuan
- Key Laboratory for Asymmetric Synthesis & Chirotechnology of Sichuan Province
- Chengdu Institute of Organic Chemistry
- Chinese Academy of Sciences
- Chengdu 610041
- China
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Ouyang XH, Song RJ, Li JH. Iron-Catalyzed Oxidative 1,2-Carboacylation of Activated Alkenes with Alcohols: A Tandem Route to 3-(2-Oxoethyl)indolin-2-ones. European J Org Chem 2014. [DOI: 10.1002/ejoc.201400043] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Zhou MB, Song RJ, Ouyang XH, Liu Y, Wei WT, Deng GB, Li JH. Metal-free oxidative tandem coupling of activated alkenes with carbonyl C(sp2)–H bonds and aryl C(sp2)–H bonds using TBHP. Chem Sci 2013. [DOI: 10.1039/c3sc50810b] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Shen K, Liu X, Zheng K, Li W, Hu X, Lin L, Feng X. Catalytic Asymmetric Synthesis of 3-(α-Hydroxy-β-carbonyl) Oxindoles by a ScIII-Catalyzed Direct Aldol-Type Reaction. Chemistry 2010; 16:3736-42. [DOI: 10.1002/chem.200903471] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Ogawa S, Shibata N, Inagaki J, Nakamura S, Toru T, Shiro M. Cinchona-Alkaloid-Catalyzed Enantioselective Direct Aldol-Type Reaction of Oxindoles with Ethyl Trifluoropyruvate. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200703317] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ogawa S, Shibata N, Inagaki J, Nakamura S, Toru T, Shiro M. Cinchona-Alkaloid-Catalyzed Enantioselective Direct Aldol-Type Reaction of Oxindoles with Ethyl Trifluoropyruvate. Angew Chem Int Ed Engl 2007; 46:8666-9. [PMID: 17912737 DOI: 10.1002/anie.200703317] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Shinichi Ogawa
- Department of Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan
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Bisset GW, Fairhall KM, Tsuji K. The effect of neosurugatoxin on the release of neurohypophysial hormones by nicotine, hypotension and an osmotic stimulus in the rat. Br J Pharmacol 1992; 106:685-92. [PMID: 1504751 PMCID: PMC1907556 DOI: 10.1111/j.1476-5381.1992.tb14395.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
1. Experiments were carried out to test whether neosurugatoxin (NSTX) which blocks autonomic ganglia also acts centrally, like hexamethonium, on nicotinic cholinoceptors involved in the neural control of release of vasopressin and oxytocin from the neurohypophysis. 2. In the water-loaded rat under ethanol anaesthesia, nicotine 100 micrograms i.v. produced a pressor and an antidiuretic response accompanied by an increase in the urinary excretion of vasopressin and of oxytocin-like radioimmunoreactivity (OLRI). This indicates release of both vasopressin and oxytocin. 3. Under conditions in which tachyphylaxis was avoided, NSTX, 80 ng i.c.v., caused a prolonged inhibition of the release of both hormones by nicotine. 4. NSTX i.c.v. caused some reduction in the pressor response to nicotine. It is suggested that this response involves both central and peripheral stimulation of the sympathetic nervous system and that the central component is blocked by neosurugatoxin. 5. Muscarine, 40 ng i.c.v., produced a pressor and an antidiuretic response with increased urinary excretion of vasopressin and OLRI. All these effects were blocked by atropine but were not inhibited by NSTX. 6. Sodium nitroprusside (SN), 200 micrograms i.v., and hypertonic saline (HS; 1.54 M NaCl solution) 4 microliters i.c.v., both produced antidiuretic responses accompanied by increased urinary excretion of vasopressin and OLRI. The ratio of the excretion of vasopressin to that of OLRI was 5.1 +/- 1.3 (mean +/- s.e.: n = 8) for SN and 1.2 +/- 0.24 (mean +/- s.e.: n = 6) for HS.NSTX 80 ng i.c.v., caused a significant reduction in the antidiuretic response to the hypotension induced with SN: the increased urinary excretion of vasopressin was also significantly reduced but not that of OLRI. NSTX had no effect on the response to HS.7. We conclude that NSTX acts centrally on nicotinic cholinoceptors to block the release of vasopressin and oxytocin by nicotine and the release of vasopressin, but not that of oxytocin, by hypotension. It does not inhibit the release of either hormone by a central osmotic stimulus.
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Affiliation(s)
- G W Bisset
- Division of Neurophysiology & Neuropharmacology, National Institute for Medical Research, Mill Hill, London
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Neosurugatoxin: A Probe for Neuronal Nicotinic Receptors in Adrenal Medulla, Brain, and Ganglia. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/b978-0-12-185266-5.50027-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Luetje CW, Wada K, Rogers S, Abramson SN, Tsuji K, Heinemann S, Patrick J. Neurotoxins distinguish between different neuronal nicotinic acetylcholine receptor subunit combinations. J Neurochem 1990; 55:632-40. [PMID: 1973456 DOI: 10.1111/j.1471-4159.1990.tb04180.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Neuronal and muscle nicotinic acetylcholine receptor subunit combinations expressed in Xenopus oocytes were tested for sensitivity to various neurotoxins. Extensive blockade of the alpha 3 beta 2 neuronal subunit combination was achieved by 10 nM neuronal bungarotoxin. Partial blockade of the alpha 4 beta 2 neuronal and alpha 1 beta 1 gamma delta muscle subunit combinations was caused by 1,000 nM neuronal bungarotoxin. The alpha 2 beta 2 neuronal subunit combination was insensitive to 1,000 nM neuronal bungarotoxin. Nearly complete blockade of all neuronal subunit combinations resulted from incubation with 2 nM neosurugatoxin, whereas 200 nM neosurugatoxin was required for partial blockade of the alpha 1 beta 1 gamma delta muscle subunit combination. The alpha 2 beta 2 and alpha 3 beta 2 neuronal subunit combinations were partially blocked by 10,000 nM lophotoxin analog-1, whereas complete blockade of the alpha 4 beta 2 neuronal and alpha 1 beta 1 gamma delta muscle subunit combinations resulted from incubation with this concentration of lophotoxin analog-1. The alpha 1 beta 1 gamma delta muscle subunit combination was blocked by the alpha-conotoxins G1A and M1 at concentrations of 100 nM. All of the neuronal subunit combinations were insensitive to 10,000 nM of both alpha-conotoxins. Thus, neosurugatoxin and the alpha-conotoxins distinguish between muscle and neuronal subunit combinations, whereas neuronal bungarotoxin and lophotoxin analog-1 distinguish between different neuronal subunit combinations on the basis of differing alpha subunits.
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Affiliation(s)
- C W Luetje
- Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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Bispyridinium (oxime) compounds antagonize the "ganglion blocking" effect of pyridostigmine in isolated superior cervical ganglia of the rat. Arch Toxicol 1990; 64:482-9. [PMID: 1980409 DOI: 10.1007/bf01977631] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The "antidotal effectiveness" of several bispyridinium compounds (HGG 12, HGG 65, HGG 70, HI 6, HLö and HLö 12) against the acetylcholinesterase (AChE) inhibitor pyridostigmine was evaluated in isolated superior cervical ganglia of the rat. Compound action potential amplitudes were inhibited by pyridostigmine in a concentration-dependent manner. HI 6 and atropine proved to be the most effective compounds in antagonizing the "ganglion blocking" action of pyridostigmine. Their relative effectiveness (PE value) was 5.4 and 4.2, respectively. All of the six bispyridinium compounds inhibited carbachol-induced, nicotinic, ganglionic surface depolarizations. The antinicotinic potencies of HI 6 and HLö 7 were about one order of magnitude lower (apparent KI values: 294 and 330 mumol/l) than the antinicotinic potencies of HGG 12, HGG 65, HGG 70 and HLö 12 (apparent KI values ranging from 19 to 41 mumol/l). The antinicotinic potencies of the bispyridinium compounds did not correlate with their in vitro protection of synaptic transmission in sympathetic ganglia. Moreover, the effectiveness of atropine points to the importance of antimuscarinic properties of possible "antidotes" for the maintenance of ganglionic transmission in cases of AChE poisoning.
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Bourke JE, Bunn SJ, Marley PD, Livett BG. The effects of neosurugatoxin on evoked catecholamine secretion from bovine adrenal chromaffin cells. Br J Pharmacol 1988; 93:275-80. [PMID: 2896033 PMCID: PMC1853793 DOI: 10.1111/j.1476-5381.1988.tb11431.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
1. The effect of neosurugatoxin (NSTX), a toxin from the Japanese ivory mollusc (Babylonia japonica), on the nicotinic response of bovine adrenal chromaffin cells was examined. 2. NSTX inhibited acetylcholine- and nicotine-induced catecholamine secretion from the cultured cells with an IC50 against 5 microM nicotine of 30 nM. 3. This inhibitory effect was reversible and independent of the presence of agonist. 4. NSTX had no effect on the catecholamine release from cultured cells evoked by 50 mM K+, or 1 microM histamine. 5. NSTX had no effect on the stimulation of phosphatidylinositol metabolism evoked by 100 microM muscarine. 6. These results suggest NSTX may be useful as a nicotinic receptor probe in tissues such as the adrenal and sympathetic ganglia where alpha-bungarotoxin is ineffective.
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Affiliation(s)
- J E Bourke
- Department of Biochemistry, University of Melbourne, Parkville, Victoria, Australia
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14
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Yamada S, Gehlert DR, Hawkins KN, Nakayama K, Roeske WR, Yamamura HI. Autoradiographic localization of nicotinic receptor binding in rat brain using [3H]methylcarbamylcholine, a novel radioligand. Life Sci 1987; 41:2851-61. [PMID: 3695812 DOI: 10.1016/0024-3205(87)90432-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Light microscopic autoradiography was used to visualize the neuroanatomical distribution of nicotinic receptors in rat brain using a novel radioligand, [3H]methylcarbamylcholine (MCC). Specific [3H]MCC binding to slide-mounted tissue sections of rat brain was saturable, reversible and of high affinity. Data analysis revealed a single population of [3H]MCC binding sites with a Kd value of 1.8 nM and Bmax of 20.1 fmol/mg protein. Nicotinic agonists and antagonists competed for [3H]MCC binding sites in slide-mounted brain sections with much greater potency than muscarinic drugs. The rat brain areas containing the highest densities of [3H]MCC binding were in thalamic regions, the medial habenular nucleus and the superior colliculus. Moderate densities of [3H]MCC binding were seen over the anterior cingulate cortex, the nucleus accumbens, the zona compacta of substantia nigra and ventral tegmental area. Low densities of [3H]MCC binding were found in most other brain regions. These data suggest that [3H]MCC selectively labels central nicotinic receptors and that these receptors are concentrated in the thalamus, the medial habenular nucleus and the superior colliculus of the rat brain.
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Affiliation(s)
- S Yamada
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Japan
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Rapier C, Wonnacott S, Lunt GG, Albuquerque EX. The neurotoxin histrionicotoxin interacts with the putative ion channel of the nicotinic acetylcholine receptors in the central nervous system. FEBS Lett 1987; 212:292-6. [PMID: 2434360 DOI: 10.1016/0014-5793(87)81363-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Perhydrohistrionicotoxin at micromolar concentrations blocked the nicotine-evoked transmitter release from perfused striatal (dopaminergic) and hippocampal (cholinergic) nerve terminals. Perhydrohistrionicotoxin failed to compete with [3H]nicotine for its high-affinity binding site in rat brain, suggesting that the action of this toxin on central nicotinic receptors is noncompetitive. From the dose-response curve, 50% inhibition of nicotine-evoked striatal dopamine release occurred at 5 microM perhydrohistrionicotoxin, a value similar to that obtained in frog sartorius muscle and Electrophorus electroplax. This close agreement may suggest that the ionic channel of the presynaptic nicotinic acetylcholine receptor of brain neurons has similar properties to those of the peripheral receptor.
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Rapier C, Harrison R, Lunt GG, Wonnacott S. Neosurugatoxin blocks nicotinic acetylcholine receptors in the brain. Neurochem Int 1985; 7:389-96. [DOI: 10.1016/0197-0186(85)90131-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/1984] [Accepted: 02/04/1985] [Indexed: 10/27/2022]
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Hayashi E, Isogai M, Kagawa Y, Takayanagi N, Yamada S. Neosurugatoxin, a specific antagonist of nicotinic acetylcholine receptors. J Neurochem 1984; 42:1491-4. [PMID: 6707649 DOI: 10.1111/j.1471-4159.1984.tb02817.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Neosurugatoxin (NSTX) (3 nM-30 nM), recently isolated from the Japanese ivory mollusc (Babylonia japonica) exerted a potent antinicotinic action in the isolated guinea pig ileum. Specific [3H]nicotine binding to rat forebrain membranes was saturable, reversible, and of high affinity. Nicotinic cholinergic agonists exhibited a markedly greater affinity for [3H]nicotine binding sites than a muscarinic agonist, oxotremorine. Although alpha-bungarotoxin had no effect on [3H]nicotine binding, low concentrations (1 nM-1 microM) of NSTX inhibited [3H]nicotine binding in the forebrain membranes and its IC50 value was 69 +/- 6 nM. On the other hand, NSTX did not affect muscarinic receptor binding in the brain. These data indicate that NSTX may be of appreciable interest as a neurotoxin with a selective affinity for ganglionic nicotinic receptors.
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Marshall LM. Synaptic localization of alpha-bungarotoxin binding which blocks nicotinic transmission at frog sympathetic neurons. Proc Natl Acad Sci U S A 1981; 78:1948-52. [PMID: 6972045 PMCID: PMC319253 DOI: 10.1073/pnas.78.3.1948] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Sympathetic neurons receive direct synaptic input from cholinergic terminal boutons of preganglionic nerve fibers. The distribution of acetylcholine receptors at these synapses is not precisely known. This study shows that alpha-bungarotoxin, which binds specifically to nicotinic receptors on skeletal muscle, also may be useful for localizing postsynaptic nicotinic receptors on principal neurons in the paravertebral sympathetic ganglia of the bullfrog. alpha-Bungarotoxin (1-5 microM) produces a block of nicotinic (fast) excitatory postsynaptic potentials that is fully reversed after 5-8 hr of washing. Dihydro-beta-erythroidine, a nicotinic antagonist, reduces the half-time of recovery from the toxin block to one-third of the control value, presumably by competing for the same receptor sites. Furthermore, the response to applied carbachol is reduced by the toxin, indicating that the block of synaptic transmission is due to a decreased response of the postsynaptic membrane. Peroxidase-labeled alpha-bungarotoxin is localized to small (0.2- to 0.5-micrometers diameter) patches beneath synaptic boutons. Peroxidase reaction product is restricted to regions of the synaptic cleft just opposite the active zones of the presynaptic terminal. In addition, peroxidase-labeled antibodies against Torpedo acetylcholine receptor bind exclusively to these same synaptic regions; evidently these patches are the areas at which nicotinic receptors are concentrated at synaptic contacts on sympathetic neurons.
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Isolation and structure determination of a new marine toxin, neosurugatoxin, from the Japanese Ivory Shell, . Tetrahedron Lett 1981. [DOI: 10.1016/s0040-4039(01)81920-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Ascher P, Large WA, Rang HP. Studies on the mechanism of action of acetylcholine antagonists on rat parasympathetic ganglion cells. J Physiol 1979; 295:139-70. [PMID: 42780 PMCID: PMC1278790 DOI: 10.1113/jphysiol.1979.sp012958] [Citation(s) in RCA: 236] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The mode of action of ACh antagonists on the parasympathetic neurones of the submandibular ganglion of the rat was studied by means of a two-micro-electrode voltage-clamp technique. The currents produced by various agonists (carbachol, ACh, suberylcholine) were studied in steady state and after voltage steps, before and after perfusion of various antagonists. 2. For three antagonists (tubocurarine, hexamethonium, decamethonium) the blocking action increases with hyperpolarization. For three other antagonists (surugatoxin, trimetaphan, mecamylamine) the effects observed at low concentrations appear to be independent of membrane potential, although in some cases voltage dependence of the block was observed for mecamylamine. 3. The blocks the 'open' channel-reception complex. The block produced by tubocurarine, hexamethonium and decamethonium increases with the agonist concentration, an observation which supports a 'sequential' scheme in which the antagonist blocks the 'open' channel-receptor complex. The block produced by trimetaphan and mecamylamine decreases slightly with increased agonist concentration, which in turn suggests that these two compounds are competitive antagonists, preventing binding of the agonists to the closed channel-receptor complex. 4. In the cases where the block is voltage dependent, voltage jumps trigger slow relaxations which are not present in control conditions. In the case of tubocurarine and hexamethonium, the relaxation following a hyperpolarizing voltage jump corresponds to a decrease in conductance. In the case of decamethonium, the slow relaxation is in the opposite direction. 5. The slow relaxations observed with tubocurarine and hexamethonium are speeded by an increase of the antagonist concentration; the slow relaxations observed with decamethonium are slowed by an increase of the decamethonium concentration. 6. The steady-state observations and the relaxations can be interpreted in terms of a scheme in which tubocurarine, hexamethonium and decamethonium act mainly by blocking the channels opened by the cholinergic agonists. 7. The two types of slow relaxation are those predicted if tubocurarine and hexamethonium dissociate slowly from the channel, and decamethonium rapidly. 8. An additional effect of tubocurarine is described, which consists of a potentiation of the rising phase of the response to an ionophoretic pulse. Possible mechanisms of this effect are discussed.
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Yamada S, Hayashi E. Effects of surugatoxin on adrenergically innervated tissues. JAPANESE JOURNAL OF PHARMACOLOGY 1979; 29:295-302. [PMID: 537251 DOI: 10.1254/jjp.29.295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Effects of surugatoxin (SGTX), a new ganglionic blocking agent on adrenergically innervated tissues: guinea pig isolated atria and vas deferens were investigated. SGTX (1, 10 muM) markedly reduced the cardiostimulatory response of the atria to nicotine and also partially the response to 1,1-dimethyl-4-phenylpiperazinium (DMPP) and 5-hydroxytryptamine, without affecting responses to noradrenaline, tyramine and histamine. The contractile response of the vas deferens to nicotine, DMPP and hypogastric nerve stimulation was markedly reduced by SGTX (1, 10 muM), whereas that to noradrenaline, acetylcholine and transmural stimulation was not affected. These results indicate that SGTX has an antagonistic action on nicotinic receptors in these tissues as well as in sympathetic ganglia and in guinea pig ileum.
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