Synaptic transmission in simple motility reflex pathways excited by distension in guinea pig distal colon Bian, X. C. en_US Heffer, L. F. en_US Gwynne, R. M. en_US Bornstein, J. C. en_US Bertrand, P. P en_US 2021-11-25T13:34:33Z 2021-11-25T13:34:33Z 2004 en_US
dc.description.abstract We examined specific receptor/transmitter combinations used at functionally identified synapses in ascending and descending reflex pathways of guinea pig distal colon. Excitatory (EJPs) or inhibitory junction potentials (IJPs) were recorded intracellularly from nicardipine-paralyzed circular smooth muscle in either the oral or anal recording chamber of a three-chambered organ bath, respectively. Blockade of synaptic transmission in the central chamber with a 0.25 mM Ca2+/12 mM Mg2+ solution abolished EJPs evoked by distension applied either in the central or the far (anal) chamber. IJPs evoked by distension in the central or the far (oral) chamber were depressed to 50% of control. Hexamethonium (nicotinic receptor antagonist, 200 µM) in the central chamber reduced IJPs evoked by far or central distension to 50%, whereas EJPs evoked by far distension were abolished and EJPs evoked by central distension were reduced to 70% of control. Hexamethonium in the recording chambers reduced both IJPs and EJPs evoked by central distension to 50%. EJPs in the ascending pathway were unaffected by blockade of muscarinic receptors in the central chamber or blockade of neurokinin 3 tachykinin receptors in this or the recording chamber. In the descending pathway, blockade of P2 receptors in the same chambers had only a minor effect on distension-evoked IJPs. Thus some intrinsic sensory neurons of guinea pig colon have long descending projections (>30 mm), but ascending projections of <15 mm. In contrast to the ileum, transmission between ascending or descending interneurons and from sensory neurons to descending interneurons is predominantly via nicotinic receptors; but transmission to inhibitory or excitatory motoneurons and from sensory neurons to ascending interneurons involves nicotinic and other unidentified receptors. en_US
dc.identifier.issn 0193-1857 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 Balloon Dilatation en_US
dc.subject.other Animals en_US
dc.subject.other Colon en_US
dc.subject.other Efferent pathways en_US
dc.subject.other Electrophysiology en_US
dc.subject.other Excitatory Postsynaptic Potentials en_US
dc.subject.other Femal en_US
dc.subject.other Gastrointestinal Motility en_US
dc.subject.other Guinea Pigs en_US
dc.subject.other In Vitro en_US
dc.subject.other Male en_US
dc.subject.other Neural Inhibition en_US
dc.subject.other Nicotinic Antagonists en_US
dc.title Synaptic transmission in simple motility reflex pathways excited by distension in guinea pig distal colon 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 5 en_US
unsw.relation.ispartofjournal American Journal of Physiology en_US
unsw.relation.ispartofpagefrompageto G1017-G1027 en_US
unsw.relation.ispartofvolume 287 en_US
unsw.relation.originalPublicationAffiliation Bian, X. C. en_US
unsw.relation.originalPublicationAffiliation Heffer, L. F. en_US
unsw.relation.originalPublicationAffiliation Gwynne, R. M. en_US
unsw.relation.originalPublicationAffiliation Bornstein, J. C. en_US
unsw.relation.originalPublicationAffiliation Bertrand, P. P, Medical Sciences, Faculty of Medicine, UNSW en_US School of Medical Sciences *
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