Biomaterial Database

Nonspiking local interneuron in the motor pattern generator for the crayfish swimmeret. 1985

D H Paul, and B Mulloney

We describe a type of nonspiking premotor local interneuron (interneuron IA) in the abdominal nervous system of Pacifasticus leniusculus. All of its branches are restricted to one side of the midline. These interneurons are identifiable and occur as bilateral pairs, one neuron on each side of abdominal ganglia 3, 4, and 5. The membrane potential of interneuron IA oscillated in phase with the swimmeret rhythm, a motor pattern generated in each of these ganglia, because the neuron received postsynaptic potentials in phase with the rhythm. Sustained hyperpolarization of an individual interneuron IA initiated generation of the swimmeret rhythm in all the ganglia of a quiescent nervous system. Sustained depolarization stopped the swimmeret rhythm in all the active ganglia of a nervous system that was generating the rhythm. Currents injected into one interneuron reset the rhythm. Comparisons of the shapes of the IA interneurons in different ganglia showed that they are similar to each other and distinct from other local interneurons in these ganglia. Interneuron IA has a large integrative segment and relatively few branches that are largely restricted to the lateral neuropil, to which all other kinds of swimmeret neurons also project. We conclude that this interneuron occurs only once in each hemiganglion in abdominal segments 3, 4, and 5, and that it is identifiable. Furthermore, this interneuron is an essential component of the circuit in each hemiganglion that generates the swimmeret rhythm. The interneuron was dye coupled to a particular identifiable motor neuron and not to any other neurons. The motor neuron was not dye-coupled to any other local interneurons. The ability of this motor neuron to reset the rhythm is attributed to its being electrically coupled to interneuron IA in its ganglion.

UI	MeSH Term	Description	Entries
D007395	Interneurons	Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.	Intercalated Neurons,Intercalated Neuron,Interneuron,Neuron, Intercalated,Neurons, Intercalated
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009068	Movement	The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.	Movements
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D010507	Periodicity	The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).	Cyclicity,Rhythmicity,Biological Rhythms,Bioperiodicity,Biorhythms,Biological Rhythm,Bioperiodicities,Biorhythm,Cyclicities,Periodicities,Rhythm, Biological,Rhythmicities,Rhythms, Biological
D003400	Astacoidea	A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.	Astacus,Crayfish,Procambarus,Astacoideas,Crayfishs
D005121	Extremities	The farthest or outermost projections of the body, such as the HAND and FOOT.	Limbs,Extremity,Limb
D005724	Ganglia	Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.
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