Three acetylcholine receptors in <i>Aplysia</i> neurones

Kehoe, Jacsue

doi:10.1113/jphysiol.1972.sp009931

Cited by 342 publications

(25 citation statements)

References 15 publications

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“…The results show certain similarities to those obtained for Aplysia neurones (Kehoe, 1972). The role of noradrenaline in the vas deferens has been questioned (Ambache & Zar, 1971;Jenkins, Marshall & Nasmyth, 1976).…”

supporting

confidence: 77%

Communications

1977

The Journal of Physiology

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supporting

confidence: 77%

Communications

1977

The Journal of Physiology

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“…The results also show that arecoline is not a cholinergic agonist in the respiratory system of Lymnaea. This has previously been reported for RC neurones of the abdominal ganglia of Aplysia (Evans & Carpenter, 1989) and arecoline also acts as a weak cholinergic agonist on H-type ACh receptors (Kehoe, 1972) in the feeding system of Lymnaea (Elliot et at. 1992 Small systems of neurones have been widely used for many years to investigate the effects of suspected neurologically active compounds.…”

Section: Psupporting

confidence: 64%

Comparative & Invertebrate Neuroscience

1996

The Journal of Physiology

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Our aim was to assess the potential application of 3-dimensional collagen gels to the study of nerve cord regeneration in the leech. Collagen, a major constituent of the extracellular matrix in vivo, has been used as a substrate for cultured mammalian cells over many decades, and collagen lattices are now widely used for the reconstruction of extracellular matrices to mimic the in vivo situation. We wanted to ascertain whether a 3-dimensional collagen matrix would support the growth of leech neurons and other cell types involved in neural repair.Collagen was prepared as an acid extract of rat tail tendons in Leibovitz-15 culture medium, and its composition and pH adjusted to give a gel that set at room temperature. Segmental ganglia or isolated lengths of connective from the ventral nerve cord of the leech Hirudo medicinalis were dissected and positioned within the gel. Once the collagen matrix had formed around the tissue, L15 culture medium containing glucose and antibiotics was added to each well.Cultures were kept at temperatures between 15 and 20 'C. In some experiments nerve cords embedded in the gel were labelled with the carbocyanine dye DiI, or fixed and stained for F-actin using rhodamine-phalloidin.Single ganglia, chains of ganglia or isolated pieces of connective were maintained in such 3-D collagen gels for up to 2 weeks. During this time nerve fibre outgrowth into the gel was consistently seen from the cut ends of both nerve roots and connectives. The gel was also clearly penetrable by cells, possibly microglial cells, migrating out from the end of cut connectives. Similar extension of neurites and emigration of cells into the gel matrix were seen from isolated pieces of connective detached from the neuron cell bodies in the ganglion. When paired connectives between two ganglia were completely severed, or when two ganglia with shortened connectives were apposed, repair occurred within the gel in such a way that the gap between the cut ends was bridged within 2-5 days in culture. Cells emigrating from the cut ends of the connectives appeared to contribute to the repair process.In summary, 3-D collagen gels provide an in vitro system in which we can reliably obtain repair of nerve cords in the dish and visualize cell behaviour underlying regenerative growth at the damage site. Experiments are in progress to investigate the effect on repair of more complex matrices created by incorporation of proteins into the collagen gel.Supported by BBSRC. (Cowden et al. 1993), suggesting that peptidergic transmission has a role in the somatic musculature. In this study we report on the action of one of these, KPNFIRFamide (PF4), which relaxes the musculature of the parasitic nematode Ascaris suum (Maule et al. 1995 PF4 hyperpolarized muscle cells (EC50 98 nM; 2-1-461 nM; n = 6) and increased input conductance (maximum at 100 uM, 8-89 + 1P52 1uS; n = 6). GABA hyperpolarized muscle cells less potently (EC50 59/sM; 50-69 FM; n = 6) and elicited a smaller maximal increase in input conductance (3-87 + 1 00 ,uS, P < 0-...

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“…Isolated medial neurons from Aplysia oculifrra pleuropedal ganglia (Kehoe, 1972) were cultured as previously described (Schacher and Proshansky, 1983). The neurons were cultured at very low densities to prevent any possible synaptic interactions among them.…”

Section: Electrophysiologymentioning

confidence: 99%

Mollusc‐specific toxins from the venom of Conus textile neovicarius

Fainzilber

Gordon

Hasson

et al. 1991

European Journal of Biochemistry

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Three peptide toxins exhibiting strong paralytic activity to molluscs, but with no paralytic effects on arthropods or vertebrates, were purified from the venom of the molluscivorous snail Conus textile neovicarius from the Red Sea. The amino acid sequences of these mollusc specific toxins are: TxIA, WCKQSGEMCNLLDQNCCDGYCIVLVCT (identical to the so called ‘King Kong peptide’); TxIB, WCKQSGEMCNVLDQNCCDGYCIVFVCT; TxIIA, WGGYSTYCγVDSγCCSDNCVRSYCT (γ=γ‐carboxyglutamate). There is a similarity of the Cys framework of these toxins to that of the ω‐conotoxins; however, their net negative charges, high content of hydrophobic residues and uneven number of Cys residues in TxIIA, are highly unusual for conotoxins. When assayed on isolated cultured Aplysia neurons, all three toxins induced membrane depolarization and spontaneous repetitive firing. The TxI toxins also induce a marked prolongation of the action potential duration, which is sodium dependent. These effects differ significantly from the blocking activities of piscivorous venom conotoxins. These mollusc specific conotoxins may therefore serve as new and selective probes for ion‐channel functions in molluscan neuronal systems.

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Three acetylcholine receptors in Aplysia neurones

Cited by 342 publications

References 15 publications

Communications

Communications

Comparative & Invertebrate Neuroscience

Mollusc‐specific toxins from the venom of Conus textile neovicarius

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