Different physiological properties in a pool of mandibular closer motor neurons in a caterpillar, Bombyx mori

2005 ◽  
Vol 374 (3) ◽  
pp. 166-170 ◽  
Author(s):  
Ken Sasaki ◽  
Kiyoshi Asaoka
Keyword(s):  
Bombyx Mori ◽  
Motor Neurons ◽  
Physiological Properties

scholarly journals Physiological and Pharmacological Studies on Cervical Motor Neurons in Slices Prepared from Neonatal and Aged Mice

2021 ◽  
pp. 1-5
Author(s):  
David O. Carpenter ◽  
N Hori ◽  
Z Xu ◽  
N Akaike ◽  
Y Tan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Motor Neurons ◽  
Excitatory Amino Acid ◽  
Lucifer Yellow ◽  
Membrane Resistance ◽  
Aged Mice ◽  
Lucifer Yellow Ch ◽  
Physiological Properties ◽  
Pharmacological Studies ◽  
Delayed Recovery

The effects of age on the physiological properties of cervical motor neurons were examined in slices made from an excised spinal cord graft of ICR mice from the second day after birth to age 350 days. The membrane potential of post-natal day 2 (PD2) to PD350 was about -65 mV and did not change greatly with age, although it was slightly higher at PD2. However, there were significant changes in membrane resistance, which increased with age from about 15 to 30 MΩ. The depolarization induced by the excitatory amino acid agonists, kainic acid, NMDA and AMPA, decreased with aging in spite of the increase in membrane resistance. The motor neurons of the aged mice showed delayed recovery from excitation caused by excitatory amino acid agonists. By injecting Lucifer yellow CH into motor neurons, it was observed that the dendrite trees become thin, and some of the dendrite branches were missing in older animals.

scholarly journals Cell-selective modulation of the Drosophila neuromuscular system by a neuropeptide

2015 ◽  
Vol 113 (5) ◽  
pp. 1631-1643 ◽  
Author(s):  
Kiel G. Ormerod ◽  
Jacob L. Krans ◽  
A. Joffre Mercier
Keyword(s):  
Motor Neurons ◽  
Input Resistance ◽  
Muscle Cells ◽  
Fruit Fly ◽  
Physiological Properties ◽  
Selective Modulation ◽  
Specific Manner ◽  
A Cell ◽  
Evoked Contractions

Neuropeptides can modulate physiological properties of neurons in a cell-specific manner. The present work examines whether a neuropeptide can also modulate muscle tissue in a cell-specific manner using identified muscle cells in third-instar larvae of fruit flies. DPKQDFMRFa, a modulatory peptide in the fruit fly Drosophila melanogaster, has been shown to enhance transmitter release from motor neurons and to elicit contractions by a direct effect on muscle cells. We report that DPKQDFMRFa causes a nifedipine-sensitive drop in input resistance in some muscle cells (6 and 7) but not others (12 and 13). The peptide also increased the amplitude of nerve-evoked contractions and compound excitatory junctional potentials (EJPs) to a greater degree in muscle cells 6 and 7 than 12 and 13. Knocking down FMRFamide receptor (FR) expression separately in nerve and muscle indicate that both presynaptic and postsynaptic FR expression contributed to the enhanced contractions, but EJP enhancement was mainly due to presynaptic expression. Muscle ablation showed that DPKQDFMRFa induced contractions and enhanced nerve-evoked contractions more strongly in muscle cells 6 and 7 than cells 12 and 13. In situ hybridization indicated that FR expression was significantly greater in muscle cells 6 and 7 than 12 and 13. Taken together, these results indicate that DPKQDFMRFa can elicit cell-selective effects on muscle fibers. The ability of neuropeptides to work in a cell-selective manner on neurons and muscle cells may help explain why so many peptides are encoded in invertebrate and vertebrate genomes.

scholarly journals Five types of nonspiking interneurons in local pattern-generating circuits of the crayfish swimmeret system

2013 ◽  
Vol 110 (2) ◽  
pp. 344-357 ◽  
Author(s):  
Carmen Smarandache-Wellmann ◽  
Cynthia Weller ◽  
Terrence M. Wright ◽  
Brian Mulloney
Keyword(s):  
Motor Neurons ◽  
Single Copy ◽  
Power Stroke ◽  
Return Stroke ◽  
Local Pattern ◽  
Local Circuit ◽  
Physiological Properties ◽  
Functional Classes ◽  
Nonspiking Interneurons ◽  
Confocal Images

We conducted a quantitative analysis of the different nonspiking interneurons in the local pattern-generating circuits of the crayfish swimmeret system. Within each local circuit, these interneurons control the firing of the power-stroke and return-stroke motor neurons that drive swimmeret movements. Fifty-four of these interneurons were identified during physiological experiments with sharp microelectrodes and filled with dextran Texas red, Neurobiotin, or both. Five types of neurons were identified on the basis of combinations of physiological and anatomical characteristics. Anatomical categories were based on 16 anatomical parameters measured from stacks of confocal images obtained from each neuron. The results support the recognition of two functional classes: inhibitors of power stroke (IPS) and inhibitors of return stroke (IRS). The IPS class of interneuron has three morphological types with similar physiological properties. The IRS class has two morphological types with physiological properties and anatomical features different from the IPS neurons but similar within the class. Three of these five types have not been previously identified. Reviewing the evidence for dye coupling within each type, we conclude that each type of IPS neuron and one type of IRS neuron occur as a single copy in each local pattern-generating circuit. The last IRS type includes neurons that might occur as a dye-coupled pair in each local circuit. Recognition of these different interneurons in the swimmeret pattern-generating circuits leads to a refined model of the local pattern-generating circuit that includes synaptic connections that encode and decode information required for intersegmental coordination of swimmeret movements.

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