Hydrozoan nematocytes send and receive synaptic signals induced by mechano-chemical stimuli

Oliver, Dominik; Brinkmann, Martin; Sieger, Thiemo; Thurm, Ulrich

doi:10.1242/jeb.018515

Cited by 18 publications

(14 citation statements)

References 36 publications

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“…Cnidocysts of cnidarians contain mechanoreceptors that along with chemoreceptors modulate the sensitivity of nematocysts. There are neural connections between cnidocysts93. Cnidocysts are distributed over most of the surface of Aurelia sp.…”

Section: Discussionmentioning

confidence: 99%

Evidence of Cnidarians sensitivity to sound after exposure to low frequency noise underwater sources

Solé¹,

Lenoir

Fontuño

et al. 2016

Sci Rep

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Jellyfishes represent a group of species that play an important role in oceans, particularly as a food source for different taxa and as a predator of fish larvae and planktonic prey. The massive introduction of artificial sound sources in the oceans has become a concern to science and society. While we are only beginning to understand that non-hearing specialists like cephalopods can be affected by anthropogenic noises and regulation is underway to measure European water noise levels, we still don’t know yet if the impact of sound may be extended to other lower level taxa of the food web. Here we exposed two species of Mediterranean Scyphozoan medusa, Cotylorhiza tuberculata and Rhizostoma pulmo to a sweep of low frequency sounds. Scanning electron microscopy (SEM) revealed injuries in the statocyst sensory epithelium of both species after exposure to sound, that are consistent with the manifestation of a massive acoustic trauma observed in other species. The presence of acoustic trauma in marine species that are not hearing specialists, like medusa, shows the magnitude of the problem of noise pollution and the complexity of the task to determine threshold values that would help building up regulation to prevent permanent damage of the ecosystems.

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Section: Discussionmentioning

confidence: 99%

Evidence of Cnidarians sensitivity to sound after exposure to low frequency noise underwater sources

Solé¹,

Lenoir

Fontuño

et al. 2016

Sci Rep

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“…Furthermore, the anatomical pathways leading from mechano-and chemoreceptors to the effector cells involved are only in part identified. Recent studies show that hydrozoan nematocytes send and receive synaptic signals upon mechano-chemical stimulation, acting as bimodal sensory cells (Thurm et al, 2004;Oliver et al, 2008).…”

Section: The Hydra Feeding Responsementioning

confidence: 99%

Coordinated modulation of cellular signaling through ligand-gated ion channels in Hydra vulgaris (Cnidaria, Hydrozoa)

Pierobon

2012

Int. J. Dev. Biol.

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Cnidarians lack well developed organs, but they have evolved the molecular and cellular components needed to assemble a nervous system. The apparent 'simplicity' of the cnidarian nervous net does not occur at the cellular level, but rather in the organisation of conducting systems. Cnidarian neurons are in fact electrically excitable, show the typical extended morphology and are connected by chemical synapses or gap junctions. They have been regarded as peptidergic, given the wealth of neuropeptides generally distributed along neurites and in cell bodies, supporting the hypothesis of a modulatory role in neurotransmission. However, the presence of clear-cored, as well as dense-cored synaptic vesicles in cnidarian neurons suggests both fast and slow synaptic transmission mechanisms. In fact, biochemical and functional evidence indicates that classical neurotransmitters and their metabolic partners are present in cnidarian tissues, where they are involved in coordinating motility and behavior. We have identified and characterized in Hydra tissues receptors to the inhibitory and excitatory amino acid neurotransmitters, GABA, glycine and NMDA, that are similar to mammalian ionotropic receptors in terms of their biochemical and pharmacological properties. These receptors appear to regulate pacemaker activities and their physiological correlates; in the live animal, they also affect feeding behavior, namely the duration and termination of the response elicited by reduced glutathione, with opposite actions of GABA and glycine or NMDA, respectively. These results suggest that modulation of cellular signaling through ligand-gated-ion channels is an ancient characteristic in the animal kingdom, and that the pharmacological properties of these receptors have been highly conserved during evolution.

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“…Synapses in cnidarians are well developed and include a variety of structures as noted above (Westfall 1996), and these appear to utilize a wide array of neurotransmitters including serotonin, dopamine, norepinephrine, GABA, glutamate, acetylcholine, and neuropeptides such as RFamide and vasopressin (Koizumi et al 2004; Westfall 2004; Oliver et al 2008; Marlow et al 2009; Kelava et al 2015; Arendt et al 2016). In spite of the wide variety of synapse types, there do not appear to be any conventional spine synapses.…”

Section: Invaginating Spine Synapses In Early Animal Evolutionmentioning

confidence: 99%

“…However, Holtmann and Thurm (2001) show a micrograph of a postsynaptic afferent ending that appears to be a spine invaginating into a “concentric” sensory hair cell of a spherical end-knob of a tentacle of the hydroid (hydra-like), Coryne tubulosa (Holtmann and Thurm 2001). In addition, in this species, the stinging cells or nematocytes (another type of sensory hair cell; Oliver et al 2008) have a basal invagination called a “basal tunnel” with a bundle of 10–20 neurites that may be in synaptic contact with the nematocyte (Holtmann and Thurm 2001). Holtmann and Thurm (2001) note that the latter structure somewhat resembles the invaginating synaptic complex of vertebrate photoreceptors (see later in this review); however, the “presynaptic” nematocyte here contains only a single large vesicle, and the neurites appear to be en passant contacts and not spines.…”

Section: Invaginating Spine Synapses In Early Animal Evolutionmentioning

confidence: 99%

The Diversity of Spine Synapses in Animals

et al. 2016

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Here we examine the structure of the various types of spine synapses throughout the animal kingdom. Based on available evidence, we suggest that there are two major categories of spine synapses: invaginating and non-invaginating, with distributions that vary among different groups of animals. In the simplest living animals with definitive nerve cells and synapses, the cnidarians and ctenophores, most chemical synapses do not form spine synapses. But some cnidarians have invaginating spine synapses, especially in photoreceptor terminals of motile cnidarians with highly complex visual organs, and also in some mainly sessile cnidarians with rapid prey capture reflexes. This association of invaginating spine synapses with complex sensory inputs is retained in the evolution of higher animals in photoreceptor terminals and some mechanoreceptor synapses. In contrast to invaginating spine synapse, non-invaginating spine synapses have been described only in animals with bilateral symmetry, heads and brains, associated with greater complexity in neural connections. This is apparent already in the simplest bilaterians, the flatworms, which can have well-developed non-invaginating spine synapses in some cases. Non-invaginating spine synapses diversify in higher animal groups. We also discuss the functional advantages of having synapses on spines and more specifically, on invaginating spines. And finally we discuss pathologies associated with spine synapses, concentrating on those systems and diseases where invaginating spine synapses are involved.

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Hydrozoan nematocytes send and receive synaptic signals induced by mechano-chemical stimuli

Abstract: Supplementary material available online at

Cited by 18 publications

References 36 publications

Evidence of Cnidarians sensitivity to sound after exposure to low frequency noise underwater sources

Evidence of Cnidarians sensitivity to sound after exposure to low frequency noise underwater sources

Coordinated modulation of cellular signaling through ligand-gated ion channels in Hydra vulgaris (Cnidaria, Hydrozoa)

The Diversity of Spine Synapses in Animals

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