The ionic mechanism associated with the action of putative transmitters on identified neurons of the snail, Helix aspersa

Bokisch, Anita J.; Walker, Robert

doi:10.1016/0742-8413(86)90088-5

Cited by 20 publications

(7 citation statements)

References 30 publications

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“…GABA is an amino acid and neurotransmitter, which can function as an inhibitory and excitatory neurotransmitter in molluscs (Yarowsky and Carpenter 1977;Bokisch and Walker 1986), and is widely recognized for its ability to induce settlement and metamorphosis of abalone, Haliotis…”

Section: Gabamentioning

confidence: 99%

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

2011

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Please cite this article as: Alfaro, Andrea C., Young, Tim, Ganesan, Annapoorna Maitrayee, Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms, Aquaculture (2011), doi: 10.1016/j.aquaculture.2011.08.038 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Pseudoalteromonas sp. AMGP1 were tested for their abilities to induce larval settlement. Toxicity effects of each treatment also were simultaneously identified by recording larval mortalities. Results indicate that all chemicals used induced larvae to settle, with acetylcholine being the most effective (~24% at 10 -6 M compared to <2% in control assays). Toxicities of treatment compounds were low at optimal settlement inducing concentrations, except for L-Tryptophan (~32%) and GABA (~59%). Our data suggest that catecholamines (and their precursors) play an important role in the biochemical mechanisms of settlement for A. maoriana. While serotonin precursors did induce low levels of larval settlement at some concentrations, high toxicity responses to 5-HTP at 10 -5 M, combined with complete settlement inhibition indicate A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTthat the mechanism of action may be more complex than can be elucidated in this study. Larval settlement responses to bacterial treatments were low for planktonic and biofilm phases across all three strains, and settlement inhibition was observed when larvae were exposed to biofilm exudates of all bacterial strains. Comparisons of A. maoriana responses to other endemic and worldwide distributed mussel species are provided as a means to highlight potential evolutionary differences in chemoreception mechanisms. Highlights 1.Mussel larval settlement responses were tested with neuroactive compounds amino acids, and bacterial biofilms.2. All chemicals induced larvae to settle, with acetylcholine being the most effective.3. Catecholamines (and their precursors) play an important role in the biochemical mechanisms of settlement for A. maoriana. Settlement responses to serotonin precursors require further investigationsince there were high toxicity responses.5. Larval settlement responses to bacterial treatments were low for planktonic and biofilm phases, and exposure to biofilm exudates resulted in settlement inhibition.

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Section: Gabamentioning

confidence: 99%

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

2011

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“…1969Pitman & Kerkut, 1970;Curtis & Johnston, Thus, whilst many of them are similar to the mami-1974; Krnjevic, 1974;Bokisch & Walker, 1986;Pinnock et al2 1988), they are consistently insensitive Author for correspondence.…”

Section: Introductionmentioning

confidence: 99%

GABA receptors on the somatic muscle cells of the parasitic nematode, Ascaris suum: stereoselectivity indicates similarity to a GABA_A‐type agonist recognition site

Holden‐Dye

Krogsgaard‐Larsen²,

Nielsen³

et al. 1989

British J Pharmacology

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1 The y-aminobutyric acid (GABA) receptors on the somatic muscle cells of Ascaris, which mediate muscle cell hyperpolarization and relaxation, have been characterized by use of intracellular recording techniques. 2 These receptors are like mammalian GABAA-receptors in that the response is mediated by an increase conductance to chloride ions. The GABAA-mimetic, muscimol, has a relative potency of 0.40 + 0.02 (n = 3) compared to GABA. 3 The stereoselectivity of the GABA receptor on Ascaris is identical to that for the mammalian GABAA-receptor, as determined from the relative potency of three pairs of enantiomers of structural analogues of GABA. 4 The most potent agonist is (S)-(+)-dihydromuscimol which is 7.53 + 0.98 (n = 5) times more potent than GABA. 5 The Ascaris GABA receptor is not significantly blocked, at concentrations below OO Mm by the potent, competitive GABAA-receptor antagonist, SR95531. 6 The Ascaris GABA receptor does not recognise agents that are known to block the GABA gated chloride channel in mammalian preparations such as t-butylbicyclophosphorothionate (TBPS, 1OpM, n = 2) or the insecticide dieldrin (100pM, n = 3). 7 GABAergic responses in Ascaris are not potentiated by pentobarbitone (100pM, n = 3) or flurazepam (100pM, n = 3). 8 The potencies of various GABA-mimetics in the Ascaris preparation have been compared with their potency at displacing GABAA-receptor binding in mammalian brain. Excluding the sulphonic acid derivatives of GABA, the correlation coefficient (r) between the potencies of compounds in the two systems is 0.74 (P < 0.01). The significance of this correlation is discussed.9 The pharmacology of the Ascaris GABA receptor is discussed in relation to other invertebrate systems and the mammalian subclassification of GABA receptors.

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“…In common with vertebrate GABA A receptors, the invertebrate GABA receptors often conduct ionic currents, but while the GABA A receptor is an inhibitory Cl~-channel, some invertebrate GABA receptors conduct cations. Thus, in molluscs, GABA can elicit an excitatory Na +current as well as an hyperpolarizing K + -current in addition to the Cl~-current (Yarowsky & Carpenter, 1978;Bokisch & Walker, 1986) and while GABA receptors act inhibitory by conducting Cl~ in the nematodes Ascaris suum and Caenorhabditis elegans, the latter also exhibits GABA-triggered excitation (Holden-Dye et al 1989;Mclntire et al 1993).…”

Section: Introductionmentioning

confidence: 99%

GABA in the nervous system of parasitic flatworms

et al. 1995

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In an immunocytochemical study, using an antiserum and a monoclonal antibody specific for the amino acid, gamma-aminobutyric acid (GABA), GABA-like immunoreactivity (GLIR) has been demonstrated for the first time in parasitic flatworms. In Moniezia expansa (Cestoda), GLIR was seen in nerve nets which were closely associated with the body wall musculature and in the longitudinal nerve cords. In the liver fluke Fasciola hepatica (Trematoda), the GLIR occurred in the longitudinal nerve cords and lateral nerves in the posterior half of the worm. GLIR was also detected in subtegumental fibres in F. hepatica. The presence of GABA was verified, using high-pressure liquid chromatography coupled with fluorescence detection. The concentration of GABA (mean +/- S.D.) in M. expansa anterior region was 124.8 +/- 15.3 picomole/mg wet weight, while in F. hepatica it was 16.8 +/- 4.9 picomole/mg. Since several insecticides and antinematodal drugs are thought to interfere with GABA-receptors, the findings indicate that GABAergic neurotransmission may be a potential target for chemotherapy in flatworms too.

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The ionic mechanism associated with the action of putative transmitters on identified neurons of the snail, Helix aspersa

Cited by 20 publications

References 30 publications

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

GABA receptors on the somatic muscle cells of the parasitic nematode, Ascaris suum: stereoselectivity indicates similarity to a GABA_A‐type agonist recognition site

GABA in the nervous system of parasitic flatworms

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The ionic mechanism associated with the action of putative transmitters on identified neurons of the snail, Helix aspersa

Cited by 20 publications

References 30 publications

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

GABA receptors on the somatic muscle cells of the parasitic nematode, Ascaris suum: stereoselectivity indicates similarity to a GABAA‐type agonist recognition site

GABA in the nervous system of parasitic flatworms

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GABA receptors on the somatic muscle cells of the parasitic nematode, Ascaris suum: stereoselectivity indicates similarity to a GABA_A‐type agonist recognition site