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Elekes K, Hiripi L, Balog G, Maász G, Battonyai I, Khabarova MY, Horváth R, Voronezhskaya EE. Serotonergic regulation of the buccal (feeding) rhythm of the pond snail, Lymnaea stagnalis. An immunocytochemical, biochemical and pharmacological approach. ACTA BIOLOGICA HUNGARICA 2018; 69:225-243. [PMID: 30257576 DOI: 10.1556/018.68.2018.3.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hatching is an important phase of the development of pulmonate gastropods followed by the adult-like extracapsular foraging life. Right before hatching the juveniles start to display a rhythmic radula movement, executed by the buccal complex, consisting of the buccal musculature (mass) and a pair of the buccal ganglia. In order to have a detailed insight into this process, we investigated the serotonergic regulation of the buccal (feeding) rhythm in 100% stage embryos of the pond snail, Lymnaea stagnalis, applying quantitative immunohistochemistry combined with the pharmacological manipulation of the serotonin (5-HT) synthesis, by either stimulating (by the 5-HT precursor 5-hydroxytryptophan, 5-HTP) or inhibiting (by the 5-HT synthesis blocker para-chlorophenylalanine, pCPA) it. Corresponding to the direction of the drug effect, significant changes of the fluorescence intensity could be detected both in the cerebral ganglia and the buccal complex. HPLC-MS assay demonstrated that 5-HTP increased meanwhile pCPA decreased the 5-HT content both of the central ganglia and the buccal complex. As to the feeding activity, 5-HTP induced only a slight (20%) increase, whereas the pCPA resulted in a 20% decrease of the radula protrusion frequency. Inhibition of 5-HT re-uptake by clomipramine reduced the frequency by 75%. The results prove the role of both central and peripheral 5-HTergic processes in the regulation of feeding activity. Application of specific receptor agonists and antagonists revealed that activation of a 5-HT1-like receptor depressed the feeding activity, meanwhile activation of a 5-HT6,7-like receptor enhanced it. Saturation binding plot of [3H]-5-HT to receptor and binding experiments performed on membrane pellets prepared from the buccal mass indicated the presence of a 5-HT6-like receptor positively coupled to cAMP. The results suggest that 5-HT influences the buccal (feeding) rhythmic activity in two ways: an inhibitory action is probably exerted via 5-HT1-like receptors, while an excitatory action is realized through 5-HT6,7-like receptors.
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Affiliation(s)
- Károly Elekes
- Department of Experimental Zoology, Balaton Limnological Institute, MTA Centre for Ecological Research, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
| | - László Hiripi
- Department of Experimental Zoology, Balaton Limnological Institute, MTA Centre for Ecological Research, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
| | - Gábor Balog
- Department of Experimental Zoology, Balaton Limnological Institute, MTA Centre for Ecological Research, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
| | - Gábor Maász
- Department of Experimental Zoology, Balaton Limnological Institute, MTA Centre for Ecological Research, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
| | - Izabella Battonyai
- Department of Experimental Zoology, Balaton Limnological Institute, MTA Centre for Ecological Research, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
| | - Marina Yu. Khabarova
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Réka Horváth
- Department of Experimental Zoology, Balaton Limnological Institute, MTA Centre for Ecological Research, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
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Potassium channels in the central nervous system of the snail, Helix pomatia: Localization and functional characterization. Neuroscience 2014; 268:87-101. [DOI: 10.1016/j.neuroscience.2014.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 01/27/2023]
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Balog G, Voronezhskaya EE, Hiripi L, Elekes K. Organization of the serotonergic innervation of the feeding (buccal) musculature during the maturation of the pond snail Lymnaea stagnalis: a morphological and biochemical study. J Comp Neurol 2012; 520:315-29. [PMID: 21674495 DOI: 10.1002/cne.22693] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The serotonergic innervation of the buccal musculature responsible for feeding (radula protraction) was investigated during the maturation of the pond snail, Lymnaea stagnalis L., applying light and electron microscopic immunohistochemistry and biochemical approaches. According to epifluorescence and laser confocal microscopy, the first 5-HT-like-immunoreactive (5-HTLIR) processes appeared on the surface of the musculature at the postmetamorphic E80% embryonic stage. Until hatching, the innervation continued to increase in density, showing axon arborizations with projections into the deeper muscle levels. An adult-like pattern of 5-HTLIR innervation appeared at P2-P3 juvenile stages. At the ultrastructural level, close (16-20 nm) but mostly unspecialized neuromuscular contacts were formed by both unlabeled and 5-HTLIR axon profiles from the E80% embryonic stage. Labeled processes were also found located relatively far from the muscle cells. An HPLC assay showed a gradual increase of the 5-HT level in the buccal mass during development. The buccal mass was characterized by a single-component high-affinity 5-HT uptake system, and 5-HT release could be evoked by 100 mM K(+) and blocked in Ca(2+) -free medium. It is suggested that 5-HT plays a wide modulatory role in the peripheral feeding system and is also involved in the functional maturation of the muscle system.
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Affiliation(s)
- Gábor Balog
- Department of Experimental Zoology, Balaton Limnological Research Institute, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
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Kiss T. Diversity and abundance: the basic properties of neuropeptide action in molluscs. Gen Comp Endocrinol 2011; 172:10-4. [PMID: 21354159 DOI: 10.1016/j.ygcen.2011.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 02/10/2011] [Accepted: 02/20/2011] [Indexed: 01/11/2023]
Abstract
Neuropeptides, the most diverse group of signaling molecules, are responsible for regulating a variety of cellular and behavioral processes in all vertebrate and invertebrate animals. The role played by peptide signals in information processing is fundamentally different from that of conventional neurotransmitters. Neuropeptides may act as neurotransmitters or neuromodulators and are released at either synaptic or non-synaptic sites. Peptide signals control developmental processes, drive specific behaviors or contribute to the mechanisms of learning and memory storage. Co-transmission within or across peptide families, and between peptide and non-peptide signaling molecules, is common; this ensures the great versatility of their action. How these tasks are fulfilled when multiple neuropeptides are released has become an important topic for peptide research. Although our knowledge concerning the physiological and behavioral roles of most of the neuropeptides isolated from molluscs is incomplete, this article provides examples to address the complexity of peptide signaling.
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Affiliation(s)
- Tibor Kiss
- Group of Comparative Neurobiology, Department of Experimental Zoology, Balaton Limnological Research Institute, HAS, Tihany, Hungary.
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