Biomaterial Database

Presynaptic inhibition: the mechanism of protection from habituation of the crayfish lateral giant fibre escape response. 1977

J S Bryan, and F B Krasne

1. Mechanism of protection from habituation of the lateral giant escape reflex of the crayfish was studied. Experiments were designed to determine whether presynaptic inhibition of primary afferents for the reflex occurs following escape command neurone firing, and if so, whether it could account for protection of the first synapse from depression. 2. Synaptic transmission between afferents and interneurone A of the escape reflex is strongly inhibited following giant fibre spikes. 3. Giant fibre firing results in post-synaptic inhibition of interneurone A. However, inhibition of afferent input to interneurone A consistently outlasts both i.p.s.p.s and post-synaptic conductance increases in the neurone; the inhibition, therefore, is probably not exclusively post-synaptic. 4. Giant fibre firing results in excitability changes in sensory afferent terminals as measured by the amplitude of antidromic compound action potentials to focal electrical stimuli applied in the region of afferent terminals in the last abdominal ganglion. The time course of this effect parallels those of protection and inhibition of the first synapse. 5. The magnitude and time course of protection and inhibition of transmission to interneurone A parallel each other closely. Both processes considerably outlast measurable signs of post-synaptic inhibition. 6. We conclude that following giant fibre activity the first synapse of the lateral giant reflex is presynaptically inhibited and the presynaptic inhibition is responsible for the protection effect described in the preceding paper.

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
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
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
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
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.
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
D006185	Habituation, Psychophysiologic	The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.	Habituation (Psychophysiology),Habituation, Psychophysiological,Psychophysiologic Habituation,Psychophysiological Habituation,Habituations (Psychophysiology)
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