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Effect of glutamate agonists bath perfusion on the response of Z. guanensis neurons to microiontophoretic glutamate application. Responses to microiontophoretically applied Glutamate (1 M, 1.5 µA, 200 ms) before (A) and after (B) bath perfusion of kainic acid (KA, 5 mM), quisqualic acid (QA, 0.4 mM) or N-methyl-D-aspartic acid (NMDA, 1 mM). The point indicates the application of glutamate. Calibration: vertical bar = 50 mV, horizontal bar = 2 s.
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In the search for new glutamate antagonists it seems promising to characterize the effects of venom from invertebrates that prey mainly on crustaceans. In this work, the exudate of the sea anemone Phyllactis flosculifera was used as a source of this type of compound. The action of chromatographic fraction D from P. flosculifera was tested upon micr...
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... neurons was done using the glutamate agonists: KA (1-5 mM, n = 7), QA (0.4-2 mM, n = 6) and NMDA (0.1-5 mM, n = 6). Typically, the effects of microintophoretic applications of glutamate were diminished by the simultaneous bath perfusion of KA and QA, whereas the perfusion of NMDA did not cause any change in the glutamate-evoked responses (Fig. ...
Citations
... Over the past several decades, various impacts of sea anemone venoms on glutamate have been documented. It was reported that the application of fraction D, derived from the sea anemone Actinostella flosculifera (Le Sueur, 1817) = (Phyllactis flosculifera), led to a reduction in the glutamatergic response (at concentrations of 2-8 mg/mL) in neurons of Z. guanensis [27]. This effect was found to be dose-dependent and could be partially reversed within approximately 30 min after washing. ...
Sea anemones are an important source of bioactive compounds with potential pharmacological applications. Their toxins are produced and stored in organelles called nematocysts and act on specific targets, including voltage-gated ion channels. To date, sea anemone toxins have demonstrated effects on voltage-gated sodium and potassium channels, facilitating investigations into the structure and function of these proteins. In this study, we evaluated the effect of Bunodeopsis globulifera sea anemone crude extract, and of a low molecular weight fraction, on voltage-gated sodium and calcium channels within the murine nervous system. Notably, the crude extract led to a significant reduction in total sodium current, while also triggering calcium-dependent glutamate release. Furthermore, the low molecular weight fraction, in particular, enhanced total calcium currents and current density. These findings underscore the existence of sea anemone toxins with diverse mechanisms of action beyond those previously documented.
... Caissarone induced twitching in electrically stimulated guinea pig ileummyenteric plexus, and this was attributed to antagonistic actions on the adenosine receptor [39]. Years later, several groups began investigating small-molecule fractions based on a study reporting the antagonism of glutamate receptors by a low molecular weight fraction from venom of the Caribbean sea anemone Phyllactis flosculifera [40]. These studies led to isolation of bunodosine 391, an acylated amino acid, from the venom of the Brazilian sea anemone Bunodosoma cangicum, which likely acts on 5-hydroxytryptamine (5-HT; serotonin) receptors. ...
Sea anemones produce venoms of exceptional molecular diversity, with at least 17 different molecular scaffolds reported to date. These venom components have traditionally been classified according to pharmacological activity and amino acid sequence. However, this classification system suffers from vulnerabilities due to functional convergence and functional promiscuity. Furthermore, for most known sea anemone toxins, the exact receptors they target are either unknown, or at best incomplete. In this review, we first provide an overview of the sea anemone venom system and then focus on the venom components. We have organised the venom components by distinguishing firstly between proteins and non-proteinaceous compounds, secondly between enzymes and other proteins without enzymatic activity, then according to the structural scaffold, and finally according to molecular target.
... Such peptides remain to be functionally characterized on a variety of tentative targets, not only voltage-gated ion channels, but also ligand-gated ion channels [2,21,28], such as glutamate-gated ion channels. Glutamate is the excitatory neurotransmitter in the crustacean neuromuscular junction [29]; therefore, it has been suggested that glutamate receptor antagonists could also be found among sea anemone toxins [30]. However, to date, no peptide acting on glutamate-gated ion channels has been characterized from sea anemones, in contrast with other venomous animals such as cone snails [31] and spiders [32]. ...
Sea anemones produce proteinaceous toxins for predation and defense, including peptide toxins that act on a large variety of ion channels of pharmacological and biomedical interest. Phymanthus crucifer is commonly found in the Caribbean Sea; however, the chemical structure and biological activity of its toxins remain unknown, with the exception of PhcrTx1, an acid-sensing ion channel (ASIC) inhibitor. Therefore, in the present work, we focused on the isolation and characterization of new P. crucifer toxins by chromatographic fractionation, followed by a toxicity screening on crabs, an evaluation of ion channels, and sequence analysis. Five groups of toxic chromatographic fractions were found, and a new paralyzing toxin was purified and named PhcrTx2. The toxin inhibited glutamate-gated currents in snail neurons (maximum inhibition of 35%, IC50 4.7 µM), and displayed little or no influence on voltage-sensitive sodium/potassium channels in snail and rat dorsal root ganglion (DRG) neurons, nor on a variety of cloned voltage-gated ion channels. The toxin sequence was fully elucidated by Edman degradation. PhcrTx2 is a new β-defensin-fold peptide that shares a sequence similarity to type 3 potassium channels toxins. However, its low activity on the evaluated ion channels suggests that its molecular target remains unknown. PhcrTx2 is the first known paralyzing toxin in the family Phymanthidae.
... Sea anemone venoms are a rich source of protein and peptide toxins, which have been characterized as pore forming membrane toxins (16)(17)(18)(19)(20) [1][2][3], serine protease inhibitors of Kunitz/BPTI family (6-7 kDa) [4][5][6] or neurotoxins acting on Kv, NaV, ASIC or TRPV channels [7][8][9][10][11][12]. Mainly in the last two decades, experimental studies have demonstrated that, in addition to proteins and peptides, these venoms contain low (smaller than 1 KDa) molecular weight compounds [13]; however, the biological activity of these molecules is still not fully characterized. Zaharenko et al., in 2011, isolated from the venom of the Brazilian sea anemone Bunodosoma cangicum, a low molecular weight (391 Da) and non-peptidic compound named Bunodosine 391 (BDS 391), composed of a bromoindole group connected to a histidine [14]. ...
Bunodosine 391 (BDS 391), a low molecular weight compound isolated from the sea anemone Bunodosoma cangicum, increases the nociceptive threshold and inhibits inflammatory hyperalgesia. Serotonin receptors are involved in those effects. In this study, we have expanded the characterization of the antinociceptive effect of BDS 391 demonstrating that, in rats: (a) the compound inhibits (1.2–12 ng/paw) overt pain, in the formalin test, and mechanical hyperalgesia (0.6–6.0 ng/paw) detected in a model of neuropathic pain; (b) intraplantar administration of ondansetron, a selective 5-HT3 receptor antagonist, blocks the effect of BDS 391, whereas ketanserin, a 5-HT2 receptor antagonist, partially reversed this effect, indicating the involvement of peripheral 5-HT2 and 5-HT3 receptors in BDS 391 antinociception; and (c) in binding assay studies, BDS 391 was not able to displace the selective 5-HT receptor antagonists, suggesting that this compound does not directly bind to these receptors. The effect of biguanide, a selective 5-HT3 receptor agonist, was also evaluated. The agonist inhibited the formalin’s nociceptive response, supporting an antinociceptive role for 5-HT3 receptors. Our study is the first one to show that a non-peptidic low molecular weight compound obtained from a sea anemone is able to induce antinociception and that activation of peripheral 5-HT3 receptors contributes to this effect.
... there are some reports of extracts as a potential source of calcium toxins [10] and a report of a 19 kDa toxin from Goniopora sp. that may act as a calcium channel activator [11]. There are no reports regarding cnidarian toxins acting on chloride channels or other kind of neuronal targets such as acetylcholine or glutamate receptors but their existence has been implied in several reports regarding the activity of sea anemone, fire corals and jellyfish venoms on these targets [12][13][14]. ...
Natural products from animal venoms have been used widely in the discovery of novel molecules with particular biologically activities that enable their use as potential drug candidates. The phylum Cnidaria (jellyfish, sea anemones, corals zoanthids, hydrozoans, etc.) is the most ancient venomous phylum on earth. Its venoms are composed of a complex mixture of peptidic compounds with neurotoxic and cytolitic properties that have shown activity on mammalian systems despite the fact that they are naturally targeted against fish and invertebrate preys, mainly crustaceans. For this reason, cnidarian venoms are an interesting and vast source of molecules with a remarkable activity on central nervous system targets, mainly voltage-gated ion channels, ASIC channels, and TRPV1 receptors. In this brief review, we list the amino acid sequences of most cnidarian neurotoxic peptides reported to date. Additionally, we propose the inclusion of a new type of voltage-gated sea anemone sodium channel toxins based on the most recent reports.
... En particular, compuestos obtenidos de anémonas marinas han sido objeto de diferentes investigaciones en Cuba (Álvarez et al., 2003, Garateix y Rodríguez, 2010. A partir de tejidos ricos en nematocistos, secreciones, así como de diferentes partes del cuerpo de estos animales, se han obtenido diversos compuestos de naturaleza proteica que incluyen las toxinas formadoras de poros o citolisinas (Lanio et al., 2001), toxinas con acción sobre canales de Na+ (Loret et al., 1994;Goudet et al., 2001) y K+ (Aneiros et al., 1993, Castañeda et al., 1995 activados por voltaje, así como otras neuro-toxinas (Garateix et al., 1990(Garateix et al., , 1992(Garateix et al., , 1996 e incluso inhibidores de proteasas (Delfín et al., 1994). Las especies de anémonas más empleadas con estos propósitos han sido: Bunodosoma granulifera, Stichodactyla helianthus, Condylactis gigantea y Phyllactis flosculifera. ...
... The previous peptidomic report employed sea anemone venom extracted by electrical stimulation of specimens in isolated marine environment [85]. Another mucus extraction methodology is based on immersion of the animals in distilled water [30,43,72], producing a sea salt-free sample without requiring any electrical equipment. However this methodology has not been combined with peptidomic studies of sea anemones. ...
Sea anemones are known to contain a wide diversity of biologically active peptides, mostly unexplored according to recent peptidomic and transcriptomic studies. In the present work, the neurotoxic fractions from the exudates of Stichodactyla helianthus and Bunodosoma granulifera were analyzed by reversed-phase chromatography and mass spectrometry. The first peptide fingerprints of these sea anemones were assessed, revealing the largest number of peptide components (156) so far found in sea anemone species, as well as the richer peptide diversity of B. granulifera in relation to S. helianthus. The transcriptomic analysis of B. granulifera, performed by massive cDNA sequencing with 454 pyrosequencing approach allowed the discovery of five new APETx-like peptides (U-AITX-Bg1a-e - including the full sequences of their precursors for four of them), which together with type 1 sea anemone sodium channel toxins constitute a very distinguishable feature of studied sea anemone species belonging to genus Bunodosoma. The molecular modeling of these new APETx-like peptides showed a distribution of positively charged and aromatic residues in putative contact surfaces as observed in other animal toxins. On the other hand, they also showed variable electrostatic potentials, thus suggesting a docking onto their targeted channels in different spatial orientations. Moreover several crab paralyzing toxins (other than U-AITX-Bg1a-e), which induce a variety of symptoms in crabs, were isolated. Some of them presumably belong to new classes of crab-paralyzing peptide toxins, especially those with molecular masses below 2kDa, which represent the smallest peptide toxins found in sea anemones.
... The preparation was kept in physiological solution for molluscans (in mmolL –1 ): NaCl 80, KCl 4, CaCl 2 7, MgCl 2 4, Tris-HCl 10 and pH adjusted to 7.4. Intracellular recording was made using glass microelectrodes fi lled with 3 molL –1 KCl and resistances ranging from 10 to 20 MΩ as previously described (Garateix et al. 1996 ...
Sticholysins I and II (St I/II) are cytolysins purified from the sea anemone Stichodactyla helianthus. In this study, we show their pharmacological action on guinea-pig and snail models in native and pH-denatured conditions in order to correlate the pharmacological findings with the pore-forming activity of both isoforms. In guinea-pig erythrocytes (N=3), St II possessed higher haemolytic activity in comparison with St I and this activity was lost at an alkaline pH. In molluscan central neurons (N=30), they irreversibly decreased the amplitude of the cholinergic response; St I (EC (50) 0.6 micromolL (-1)) was more potent than St II (EC50 > 6.6 micromolL (-1)) and they both increased the duration of the action potential; these effects were absent at an alkaline pH. In guinea-pig isolated atrium (N=25), both increased the amplitude of the contraction force, but St II was more potent than St I (EC (50) 0.03 micromolL (-1) and 0.3 micromolL (-1), respectively) and this effect persisted at an alkaline pH. In summary, both cytolysins have neuroactive and cardioactive properties. The main mechanism in molluscan neurons seems to be associated with the cytolytic activity of these molecules, whereas inguinea-pig atrium, the existence of an additional pharmacological mechanism might be contributing to the observed effect.
... For example, extracts of cultured bacteria associated with the marine sponge Halichondria panacea activate rat cortical NMDA receptors; the active principle(s) were not further isolated, however (Perovic et al. 1998). Garateix and colleagues carried out an ecologically-inspired search for iGluR lig-ands from marine organisms that prey on crustaceans, leading to the discovery of bioactive peptide-containing fractions from a sea anemone, Phyllactis flosculifera (Garateix et al. 1996). Peptide fractions of extracts from the animal diminished both the excitatory and the inhibitory responses to glutamate agonists in neurons of the land snail Zachrysia guanensisin. ...
Marine-derived small molecules and peptides have played a central role in elaborating pharmacological specificities and neuronal functions of mammalian ionotropic glutamate receptors (iGluRs), the primary mediators of excitatory synaptic transmission in the central nervous system (CNS). As well, the pathological sequelae elicited by one class of compounds (the kainoids) constitute a widely-used animal model for human mesial temporal lobe epilepsy (mTLE). New and existing molecules could prove useful as lead compounds for the development of therapeutics for neuropathologies that have aberrant glutamatergic signaling as a central component. In this chapter we discuss natural source origins and pharmacological activities of those marine compounds that target ionotropic glutamate receptors.
... A similar result of the inhibition of glutamate binding has been reported for some spider venoms (Michaelis et al., 1984). Furthermore, antagonism of glutamate receptors by a toxin from the sea anemone Physalia physalis (Mas et al., 1989), and by a fraction from the sea anemone Phyllactis flosculifera, has also been demonstrated (Garateix et al., 1996). ...
The crude extract from the sea anemone, Bunodosoma caissarum caused dose-dependent convulsions by i.c.v. route in mice. The involvement of the glutamatergic system in the convulsions was investigated. MK-801 and ketamine, non-competitive NMDA receptor antagonists, prolonged the latencies for convulsion onset. AP-5, a competitive NMDA receptor antagonist, reduced the number of animals convulsing and also increased the latency for convulsion onset. 7-Chlorokynurenic acid, an antagonist of the glycine site on the NMDA receptor, reduced the incidence of convulsions. GMP, a nucleotide known to antagonize some NMDA actions, reduced the incidence and the severity of convulsions and prolonged the latency for their onset. Riluzole, a neuroprotective and anticonvulsant agent, blocked the appearance of convulsions. In vitro, the crude extract inhibited [3H]glutamate binding to cerebral cortical membranes and enhanced [3H]glutamate release from cortical synaptosomes. Heating the crude extract to 100 degrees C for 30 min or preincubating it with sphingomyelin, abolished its effect on glutamate release, but did not alter its ability to induce convulsions and to inhibit glutamate binding. However, the convulsant action was inhibited when the crude extract was submitted to trypsin treatment. Our data suggest that the convulsions elicited by the crude extract are not due to the presence of cytolysin and are not related to an increase in glutamate release, but seem to be dependent on the interaction between a peptide component of the extract and NMDA receptors.