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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2002-4-17
pubmed:abstractText
Previous experiments have shown that prolonged low frequency stimulation of presynaptic inputs causes excitation of AH neurones that considerably outlasts the period of stimulation in the guinea-pig small intestine. The present experiments compare the responses of S neurones (which are motor neurones and interneurones) with responses of AH neurones (intrinsic primary afferent neurones) to low frequency stimulation of synaptic inputs. Neurones in the myenteric plexus of isolated segments of guinea-pig small intestine were recorded from with intracellular microelectrodes. During their impalement, the neurones were filled with a marker dye and they were later processed to reveal their shapes and immunohistochemical properties. One group of neurones, inhibitory motor neurones to the circular muscle, was depolarised by stimulation of synaptic inputs at 1 Hz for 100 s to 4 min. With 4-min trains of stimuli, peak depolarisation was 21+/-2 mV (mean+/-S.E.M.), which was reached at about 110 s. Depolarisation was accompanied by increased excitability; before stimulation, a test intracellular pulse (500 ms) triggered 3 action potentials, at the peak of excitability this reached 16 action potentials. Depolarisation began to decline immediately at the end of stimulation. This contrasts with responses of AH neurones, in which depolarisation persisted after the end of the stimulus (peak depolarisation at 300 s). The excitation and depolarisation of inhibitory motor neurones was blocked by the neurokinin 1 tachykinin receptor antagonist, SR140333 (100 nM), but excitation of AH neurones was not affected. Small or no responses to 1 Hz stimulation were recorded from descending filamentous interneurones, longitudinal muscle motor neurones and excitatory circular muscle motor neurones. In conclusion, this study indicates that sustained slow postsynaptic excitation only occurs in AH neurones, and that one type of S neurones, inhibitory motor neurones to the circular muscle, responds substantially, but not beyond the period of stimulation, to activation of synaptic inputs at 1 Hz. This slow excitatory postsynaptic potential evoked by low frequency stimulation is mediated by tachykinins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:volume
110
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
361-73
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11958877-Action Potentials, pubmed-meshheading:11958877-Animals, pubmed-meshheading:11958877-Axons, pubmed-meshheading:11958877-Cell Size, pubmed-meshheading:11958877-Electric Stimulation, pubmed-meshheading:11958877-Female, pubmed-meshheading:11958877-Ganglionic Blockers, pubmed-meshheading:11958877-Guinea Pigs, pubmed-meshheading:11958877-Hexamethonium, pubmed-meshheading:11958877-Interneurons, pubmed-meshheading:11958877-Male, pubmed-meshheading:11958877-Motor Neurons, pubmed-meshheading:11958877-Myenteric Plexus, pubmed-meshheading:11958877-Neural Conduction, pubmed-meshheading:11958877-Neural Inhibition, pubmed-meshheading:11958877-Neural Pathways, pubmed-meshheading:11958877-Neurons, pubmed-meshheading:11958877-Receptors, Tachykinin, pubmed-meshheading:11958877-Synapses, pubmed-meshheading:11958877-Synaptic Transmission, pubmed-meshheading:11958877-Tachykinins, pubmed-meshheading:11958877-Tetrodotoxin
pubmed:year
2002
pubmed:articleTitle
Responses of myenteric S neurones to low frequency stimulation of their synaptic inputs.
pubmed:affiliation
Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Vic., Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't