Neuroactive substances specifically modulate rhythmic body contractions in the nerveless metazoon Tethya wilhelma (Demospongiae, Porifera)

BACKGROUND: Sponges (Porifera) are nerve- and muscleless metazoa, but display coordinated motor reactions. Therefore, they represent a valuable phylum to investigate coordination systems, which evolved in a hypothetical Urmetazoon prior to the central nervous system (CNS) of later metazoa. We have chosen the contractile and locomotive species Tethya wilhelma (Demospongiae, Hadromerida) as a model system for our research, using quantitative analysis based on digital time lapse imaging. In order to evaluate candidate coordination pathways, we extracorporeally tested a number of chemical messengers, agonists and antagonists known from chemical signalling pathways in animals with CNS. RESULTS: Sponge body contraction of T. wilhelma was induced by caffeine, glycine, serotonine, nitric oxide (NO) and extracellular cyclic adenosine monophosphate (cAMP). The induction by glycine and cAMP followed patterns varying from other substances. Induction by cAMP was delayed, while glycine lead to a bi-phasic contraction response. The frequency of the endogenous contraction rhythm of T. wilhelma was significantly decreased by adrenaline and NO, with the same tendency for cAMP and acetylcholine. In contrast, caffeine and glycine increased the contraction frequency. The endogenous rhythm appeared irregular during application of caffeine, adrenaline, NO and cAMP. Caffeine, glycine and NO attenuated the contraction amplitude. All effects on the endogenous rhythm were neutralised by the washout of the substances from the experimental reactor system. CONCLUSION: Our study demonstrates that a number of chemical messengers, agonists and antagonists induce contraction and/or modulate the endogenous contraction rhythm and amplitude of our nerveless model metazoon T. wilhelma. We conclude that a relatively complex system of chemical messengers regulates the contraction behaviour through auto- and paracrine signalling, which is presented in a hypothetical model. We assume that adrenergic, adenosynergic and glycinergic pathways, as well as pathways based on NO and extracellular cAMP are candidates for the regulation and timing of the endogenous contraction rhythm within pacemaker cells, while GABA, glutamate and serotonine are candidates for the direct coordination of the contractile cells

Evolutionary origin of synapses and neurons – Bridging the gap

The evolutionary origin of synapses and neurons is an enigmatic subject that inspires much debate. Non-bilaterian metazoans, both with and without neurons and their closest relatives already contain many components of the molecular toolkits for synapse functions. The origin of these components and their assembly into ancient synaptic signaling machineries are particularly important in light of recent findings on the phylogeny of non-bilaterian metazoans. The evolution of synapses and neurons are often discussed only from a metazoan perspective leaving a considerable gap in our understanding. By taking an integrative approach we highlight the need to consider different, but extremely relevant phyla and to include the closest unicellular relatives of metazoans, the ichthyosporeans, filastereans and choanoflagellates, to fully understand the evolutionary origin of synapses and neurons. This approach allows for a detailed understanding of when and how the first pre- and postsynaptic signaling machineries evolved

Evolutionary origin of synapses and neurons - Bridging the gap

The evolutionary origin of synapses and neurons is an enigmatic subject that inspires much debate. Non-bilaterian metazoans, both with and without neurons and their closest relatives already contain many components of the molecular toolkits for synapse functions. The origin of these components and their assembly into ancient synaptic signaling machineries are particularly important in light of recent findings on the phylogeny of non-bilaterian metazoans. The evolution of synapses and neurons are often discussed only from a metazoan perspective leaving a considerable gap in our understanding. By taking an integrative approach we highlight the need to consider different, but extremely relevant phyla and to include the closest unicellular relatives of metazoans, the ichthyosporeans, filastereans and choanoflagellates, to fully understand the evolutionary origin of synapses and neurons. This approach allows for a detailed understanding of when and how the first pre- and postsynaptic signaling machineries evolved

Spongiaires. — Anatomie, Physiologie, Systématique, Ecologie. Tome III, Fascicule I du Traité de Zoologie dirigé par P.-P. Grasse

Pavans de Ceccatty M. Spongiaires. — Anatomie, Physiologie, Systématique, Ecologie. Tome III, Fascicule I du Traité de Zoologie dirigé par P.-P. Grasse. In: Bulletin mensuel de la Société linnéenne de Lyon, 44ᵉ année, n°8, octobre 1975. pp. 287-288

Spongiaires. — Anatomie, Physiologie, Systématique, Ecologie. Tome III, Fascicule I du Traité de Zoologie dirigé par P.-P. Grasse

Pavans de Ceccatty M. Spongiaires. — Anatomie, Physiologie, Systématique, Ecologie. Tome III, Fascicule I du Traité de Zoologie dirigé par P.-P. Grasse. In: Bulletin mensuel de la Société linnéenne de Lyon, 44ᵉ année, n°8, octobre 1975. pp. 287-288

Traité de Zoologie (Anatomie, Systématique, Biologie ), publié sous la direction de M. Pierre-P. Grasse. — Tome V (fascicules I et II) : Annélides, Myzostomides, Sipunculiens, Echiuriens, Priapuliens, Endoproctes, Phoronidiens : Bryozoaires, Brachiopodes, Chétognathes, Pogonophores, Mollusques, Paris

Pavans de Ceccatty M. Traité de Zoologie (Anatomie, Systématique, Biologie ), publié sous la direction de M. Pierre-P. Grasse. — Tome V (fascicules I et II) : Annélides, Myzostomides, Sipunculiens, Echiuriens, Priapuliens, Endoproctes, Phoronidiens : Bryozoaires, Brachiopodes, Chétognathes, Pogonophores, Mollusques, Paris. In: Bulletin mensuel de la Société linnéenne de Lyon, 29ᵉ année, n°9, novembre 1960. pp. 278-280

Histo-physiologie des corrélations neuro-hormonales lors du cycle sexuel de Gundlachia

Wautier Jacques, Pavans de Ceccatty M., Hernandez M.-L., Richardot M., Buisson B. Histo-physiologie des corrélations neuro-hormonales lors du cycle sexuel de Gundlachia. In: Bulletin mensuel de la Société linnéenne de Lyon, 31ᵉ année, n°3, mars 1962. pp. 84-92