Influence of the mucosa on the excitability of myenteric neurons Kunze, W. A. en_US Bertrand, P. P en_US Furness, J. B. en_US Bornstein, J. C. en_US 2021-11-25T13:35:31Z 2021-11-25T13:35:31Z 1997 en_US
dc.description.abstract Intracellular microelectrodes were used to examine the active and passive membrane properties of neurons in the myenteric plexus of the guinea-pig small intestine. Neurons of two types were examined: S neurons, which have prominent fast excitatory postsynaptic potentials and in which action potentials are not followed by long-lasting afterhyperpolarizations, and AH neurons, which have long-lasting afterhyperpolarizations following soma action potentials. In preparations in which the myenteric ganglia and longitudinal muscle, but no mucosa, were present, most S neurons (59/64) responded to intracellular depolarizing current with brief bursts of action potentials. Regardless of the strength of a depolarizing current of 500- ms duration, these neurons never fired action potentials beyond the first 250 ms. S neurons in this state were called rapidly accommodating. In contrast, within 600 microm circumferential to the intact mucosa, 26/58 S neurons fired action potentials for most or all of the period of a 500-ms insightful depolarizing pulse. S neurons in this state were called slowly accommodating. Depolarization of S neurons in the rapidly accommodating state caused a rapidly developing reduction in membrane resistance (outward rectification; onset about 7 ms). This rectification was absent from S neurons in the slowly accommodating state. Tetraethylammonium blocked the early rectification and the changed neuronal state from rapidly accommodating to slowly accommodating. Application of tetrodotoxin to neurons in the slowly accommodating state revealed the early rectification, indicating that its absence from these neurons before tetrodotoxin was applied had been due to ongoing activity in axons providing synaptic input to the neurons. After the mucosa was disconnected from the other layers and laid back in its original position, all S neurons close to the mucosa were in the rapidly accommodating state (17/17). Slow excitatory postsynaptic potentials, evoked by electrical stimulation of nerve tracts, converted 17 of 43 S neurons from rapidly accommodating to slowly accommodating and eliminated the early outward rectification in these neurons. These results indicate that the action potential firing properties of S neurons can be changed by external influences, including the activity of synaptic inputs that release a slowly acting transmitter. Spontaneous antidromic action potentials were recorded in 8/62 AH neurons within 600 microm circumferential to the intact mucosa. It is concluded that, when the mucosa is intact, a background firing of sensory neurons occurs which leads to a state change in many S neurons innervated by the active sensory neurons. We conclude that this state change is caused by the block of a voltage-sensitive outward rectification. en_US
dc.identifier.issn 0306-4522 en_US
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.subject.other sensory en_US
dc.subject.other mechanism en_US
dc.title Influence of the mucosa on the excitability of myenteric neurons en_US
dc.type Journal Article en
dcterms.accessRights metadata only access
dspace.entity.type Publication en_US
unsw.identifier.doiPublisher en_US
unsw.relation.faculty Medicine & Health
unsw.relation.ispartofissue 2 en_US
unsw.relation.ispartofjournal Neuroscience en_US
unsw.relation.ispartofpagefrompageto 619-634 en_US
unsw.relation.ispartofvolume 76 en_US
unsw.relation.originalPublicationAffiliation Kunze, W. A. en_US
unsw.relation.originalPublicationAffiliation Bertrand, P. P, Medical Sciences, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Furness, J. B. en_US
unsw.relation.originalPublicationAffiliation Bornstein, J. C. en_US School of Medical Sciences *
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