Biomaterial Database

The effects of axotomy on bullfrog sympathetic neurones. 1987

T Gordon, and M E Kelly, and E J Sanders, and J Shapiro, and P A Smith

Department of Pharmacology, University of Alberta, Edmonton, Canada.

1. The effects of axotomy on the electrical properties of B cells in paravertebral sympathetic ganglia were studied using standard intracellular recording techniques. The effects were apparent after 1 week and persisted throughout the 47 days of study. 2. Action potential duration (spike width) and amplitude (spike height) were significantly increased in axotomized neurones. 3. The duration of the after-hyperpolarization which followed the action potential showed considerable scatter in control neurones (mean +/- S.E. of mean, 159.0 +/- 5.8 ms for 100 cells). Following axotomy, the duration was significantly reduced (50.9 +/- 2.3 ms for 97 cells). The amplitude of the after-hyperpolarization was also significantly smaller in axotomized neurones. 4. Changes in the characteristics of the action potential and the after-hyperpolarization in axotomized neurones were not due to alteration in resting membrane potential or input resistance which were unchanged after axotomy. Rheobase current was significantly increased. 5. There was neither a significant depression of the rate of rise or the amplitude of orthodromically evoked nicotinic e.p.s.p.s nor any obvious ultrastructural alteration following axotomy. 6. Despite the decrease in the duration of the after-hyperpolarization, the rate of discharge in response to constant current injection was little changed in axotomized neurones. 7. Although axotomy produces significant changes in several measurable electrophysiological parameters in bullfrog sympathetic ganglion cells, the present results imply that mature neurones are able to maintain relatively normal electrical activity despite injury.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
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
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011892	Rana catesbeiana	A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.	Bullfrog,Bullfrogs,Rana catesbeianas,catesbeiana, Rana
D005728	Ganglia, Sympathetic	Ganglia of the sympathetic nervous system including the paravertebral and the prevertebral ganglia. Among these are the sympathetic chain ganglia, the superior, middle, and inferior cervical ganglia, and the aorticorenal, celiac, and stellate ganglia.	Celiac Ganglia,Sympathetic Ganglia,Celiac Ganglion,Ganglion, Sympathetic,Ganglia, Celiac,Ganglion, Celiac,Sympathetic Ganglion
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
D013127	Spinal Nerves	The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included.	Nerve, Spinal,Nerves, Spinal,Spinal Nerve