Effect of putative neuromodulators on rhythmic buccal motor output in <i>Lymnaea stagnalis</i>

Kyriakides, Michael; McCrohan, Catherine R.

doi:10.1002/neu.480200704

Cited by 70 publications

(40 citation statements)

References 33 publications

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“…Feeding-induced arousal and food intake in snails are regulated to a large extent by serotonergic 5-hydroxytryptamine (5-HT) and dopaminergic neurons (Murphy 2001, Elliott & Susswein 2002. FMRFamide and FMRFamide-containing pleural neurons both inhibit feeding and facilitate withdrawal behaviour in various gastropod species (Kyriakides & McCrohan 1989, Murphy 1990, Alania et al 2004. This is achieved by FMRFamide rapidly attenuating the rhythmic firing of buccal and cerebral ganglion neurons responsible for initiating and maintaining the repetitive motor outputs required for feeding (Alania et al 2004).…”

Section: Gastropodsmentioning

confidence: 99%

The role of RFamide peptides in feeding

Bechtold

Luckman

2007

Journal of Endocrinology

116

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In the three decades since FMRFamide was isolated from the clam Macrocallista nimbosa, the list of RFamide peptides has been steadily growing. These peptides occur widely across the animal kingdom, including five groups of RFamide peptides identified in mammals. Although there is tremendous diversity in structure and biological activity in the RFamides, the involvement of these peptides in the regulation of energy balance and feeding behaviour appears consistently through evolution. Even so, questions remain as to whether feedingrelated actions represent a primary function of the RFamides, especially within mammals. However, as we will discuss here, the study of RFamide function is rapidly expanding and with it so is our understanding of how these peptides can influence food intake directly as well as related aspects of feeding behaviour and energy expenditure.

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Section: Gastropodsmentioning

confidence: 99%

The role of RFamide peptides in feeding

Bechtold

Luckman

2007

Journal of Endocrinology

116

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“…Here we report the results of an electrophysiological study of the effects of NO on the serotonergic synapse between the cerebral giant cells (CGCs) and B4 motoneurons in the feeding system of the pond snail Lymnaea stagnalis. The CGCs are an important pair of modulatory neurons with wide ranging effects on Lymnaea feeding behavior including arousal, "gating, " frequency control, and long-term memory formation (Kemenes et al 2006;Kyriakides and McCrohan 1989;Yeoman et al 1994a,b). These effects are mediated via serotonergic synapses between the CGC and feeding interneurons and motoneurons including B4 (McCrohan and Benjamin 1980;Yeoman et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Modulation of Serotonergic Neurotransmission by Nitric Oxide

Straub

Grant²,

O’Shea³

et al. 2007

Journal of Neurophysiology

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tric oxide (NO) and serotonin (5-HT) are two neurotransmitters with important roles in neuromodulation and synaptic plasticity. There is substantial evidence for a morphological and functional overlap between these two neurotransmitter systems, in particular the modulation of 5-HT function by NO. Here we demonstrate for the first time the modulation of an identified serotonergic synapse by NO using the synapse between the cerebral giant cell (CGC) and the B4 neuron within the feeding network of the pond snail Lymnaea stagnalis as a model system. Simultaneous electrophysiological recordings from the pre-and postsynaptic neurons show that blocking endogenous NO production in the intact nervous system significantly reduces the B4 response to CGC activity. The blocking effect is frequency dependent and is strongest at low CGC frequencies. Conversely, bath application of the NO donor DEA/NONOate significantly enhances the CGC-B4 synapse. The modulation of the CGC-B4 synapse is mediated by the soluble guanylate cyclase (sGC)/cGMP pathway as demonstrated by the effects of the sGC antagonist 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). NO modulation of the CGC-B4 synapse can be mimicked in cell culture, where application of 5-HT puffs to isolated B4 neurons simulates synaptic 5-HT release. Bath application of diethylamine NONOate (DEA/NONOate) enhances the 5-HT induced response in the isolated B4 neuron. However, the cell culture experiment provided no evidence for endogenous NO production in either the CGC or B4 neuron suggesting that NO is produced by an alternative source. Thus we conclude that NO modulates the serotonergic CGC-B4 synapse by enhancing the postsynaptic 5-HT response.

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“…Although dopamine can activate the fictive feeding pattern in the snail CNS as can the SO and NIL interneurons (Trimble and Barker, 1984;Wieland and Gelperin, 1983;Kyriakides and McCrohan, 1989), we have not found pharmacological evidence that either the SO or the N1L releases dopamine or makes a direct contribution to dopaminergic transmission in any way. Since the buccal ganglia contain dopamine-positive cell bodies (Elekes et al, 1991), the role of dopaminergic feeding neurons (cf.…”

Section: Discussionmentioning

confidence: 58%

“…Another candidate for neurotransmitters involved in connections between the feeding intemeurons was dopamine, since dopamine applied to the tissue bath is able to evoke a strong fictive feeding rhythm in which the N1 phase is enhanced (Limax, Wieland and Trimble and Barker, 1984;Lymnaea, Kyriakides and McCrohan, 1989). Moreover in their histochemical work Elekes et al (1991) showed dopamine immunoreactive cells present in the buccal ganglia of Lymnaea close to the location of the SO and N1L inteneurons (either of which can drive fictive feeding similar to the dopamine-evoked pattern when electrically stimulated).…”

Section: Introductionmentioning

confidence: 99%

The hybrid modulatory/pattern generating N1L interneuron in the buccal feeding system ofLymnaea is cholinergic

Vehovszky

Elliott

1995

Invertebrate Neuroscience

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This study examines neurotransmission between identified buccal interneurons in the feeding system of the snail Lymnaea stagnalis. We compare the pharmacology of the individual synaptic connections from a hybrid modulatory/pattern generating interneuron (N1L) to a pattern generating interneuron (N1M) with that from a modulatory interneuron (SO) to the same follower cell (N1M). The pharmacological properties of the N1L to N1M and the SO to N1M connections closely resemble each other. Both interneurons produce fast cholinergic EPSPs as judged by the blocking effects of cholinergic antagonists hexamethonium, d-tubocurarine and the cholinergic neurotoxin AF-64A. A slower, more complex but non-cholinergic component of the synaptic response is also present after stimulating either the presynaptic N1L or SO interneurons. This second component of the postsynaptic response is not dopaminergic, on the basis of its persistence in the presence of dopaminergic antagonists ergometrine and fluphenazine and the dopaminergic neurotoxin MPP+. We conclude that, although there has been an evolutionary divergence in function, the modulatory SO and the hybrid modulatory/pattern generating N1L are pharmacologically similar. Neither of them contributes directly to dopaminergic modulation of the feeding activity. These neurons also resemble the N1M protraction phase pattern generating neurons which are cholinergic (Elliott and Kemenes, 1992).

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Effect of putative neuromodulators on rhythmic buccal motor output in Lymnaea stagnalis

Cited by 70 publications

References 33 publications

The role of RFamide peptides in feeding

The role of RFamide peptides in feeding

Modulation of Serotonergic Neurotransmission by Nitric Oxide

The hybrid modulatory/pattern generating N1L interneuron in the buccal feeding system ofLymnaea is cholinergic

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