Biomaterial Database

Decremental propagation of reflex spikes along giant axons of the earthworm Amynthas hawayanus. 1990

Z Assmé, and Y C Chang

Departamento de Fisiologia, Universidade Federal do Paraná, Curitiba, PR, Brasil.

The constant-velocity conduction of an action potential evoked by stimulating the isolated nerve cord of the earthworm Amynthas hawayanus differs from the propagation of a reflex spike evoked by stimulating the epithelium of an epithelio-muscular-nerve-cord (EMNC) preparation and recorded between pairs of microelectrodes spaced every 10 segments along either giant axon. The reflex spike is decremental and lasts for no more than 20 segments before it eventually disappears. Secondary and tertiary spikes sometimes arise even before the disappearance of the primary spike, and disappear after propagating for a short distance. This decremental propagation is tentatively attributed to the summation of excitatory postsynaptic potentials from the synaptic impingings of afferent interneurons in a polysynaptic reflex arc.

UI	MeSH Term	Description	Entries
D009835	Oligochaeta	A class of annelid worms with few setae per segment. It includes the earthworms such as Lumbricus and Eisenia.	Earthworms,Eisenia foetida,Eisenia worm,Lumbricus,Lumbricus terrestris,Eisenia fetida,Earthworm,Eisenia fetidas,Eisenia foetidas,Eisenia worms,Lumbricus terrestri,Oligochaetas,fetida, Eisenia,foetidas, Eisenia,terrestris, Lumbricus,worm, Eisenia
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001369	Axons	Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.	Axon