A new inhibitory pathway in the jellyfishPolyorchis penicillatus
| Autor: | George O. Mackie, Robert W Meech, A. N. Spencer |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Tentacle
biology Neurite Nerve plexus Anatomy biology.organism_classification Inhibitory postsynaptic potential Nerve conduction velocity Polyorchis medicine.anatomical_structure Postsynaptic potential medicine Biophysics Animal Science and Zoology Reversal potential Ecology Evolution Behavior and Systematics |
| Zdroj: | Canadian Journal of Zoology. 90:172-181 |
| ISSN: | 1480-3283 0008-4301 |
| DOI: | 10.1139/z11-124 |
| Popis: | Contact of food with the manubrial lips in the genus Polyorchis A. Agassiz, 1862 evokes trains of electrical impulses (E potentials) that propagate to the margin. E potentials are also produced by food stimuli at the margin and tentacle bases. E potentials are shown to be associated with inhibitory postsynaptic potentials (ipsps) in the swimming motor neurons and contribute to the arrest of swimming during feeding. The conduction pathway for E potentials is a nerve plexus located in the endodermal walls of the stomach and radial and ring canals. We have explored the conducting properties of the system; the conduction velocity varies with stimulus frequency but is about 15 cm/s when stimuli are more than 50 s apart. Neurites belonging to the E system run around the margin adjacent to the inner nerve ring, where the swimming pacemaker neurons are located. We suggest that they may make inhibitory synapses on to the swimming motor neurons, but this has yet to be demonstrated anatomically. The reversal potential for ipsps, recorded intracellularly with potassium acetate micropipettes, was estimated to be about –69 mV. Swimming inhibition mediated by this endodermal pathway is distinct from that observed during protective “crumpling” behaviour and that associated with contractions of the radial muscles seen during feeding, though it may accompany the latter. |
| Databáze: | OpenAIRE |
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