{"id":{"repo_id":"ottawa-retro","oai_identifier":"oai:ruor.uottawa.ca:10393/6334"},"canonical_url":"https://search.dev.ndltd.org/etd/ottawa-retro/oai:ruor.uottawa.ca:10393/6334","repository":{"repo_id":"ottawa-retro","name":"University of Ottawa","base_url":"https://ruor.uottawa.ca/server/oai/request"},"display":{"title":"Mechanisms of neuronal integration in adrenomedullary sympathetic preganglionic neurons.","abstract":"Sympathetic preganglionic neurons innervating the adrenal medulla (AD-SPN) regulate the release of adrenal catecholamines into the bloodstream. This research was undertaken to investigate the intrinsic properties and synaptic pathways characteristic of AD-SPN in neonatal rat spinal cord slice preparation. The presence of Lucifer Yellow from the patch pipette and Rhodamine-Dextran-Lysine from the adrenal medulla in the same neuron post recording identified AD-SPN. Active intrinsic properties revealed and characterised include: a potassium-mediated transient outward rectification present in 96% of AD-SPN and separable into a short 4-aminopyridine- and a long barium-sensitive component; a potassium-mediated sustained outward rectification revealed in TTx, activated positive to -50mV and blocked with quinine. These conductances contribute to the repolarising phase of the action potential. 89% of AD-SPN possessed potassium-mediated anomalous inward rectification. All AD-SPN displayed a high voltage-activated calcium spike that prolongs the action potential. The addition of internal caesium (140mM) revealed a low threshold spike mediated by T-type calcium channels that serve to facilitate burst firing. 75% of AD-SPN exhibited evidence of electrotonic coupling, indicated by characteristic oscillations in membrane potential and confirmed with dual recordings from electrotonically coupled AD-SPN. Electrotonic coupling promoted synchronous activity. An enhanced afterhyperpolarising potential facilitated transient termination of action potential firing forming bursts of activity. A role for calcium in the regulation of neuronal activity via action on electrotonic coupling was suggested by caffeine (10mM) decreasing, BAPTA-AM (15muM) and calcium free aCSF increasing the junctional conductance. Electrical stimulation of the descending fibres in both the ipsi- and contralateral funiculi evoked fast EPSPs in all AD-SPN that were mediated by both NMDA and non-NMDA receptors. A subpopulation of AD-SPN received fast IPSPs mediated by GABA acting via GABAA receptors. A train of stimuli (4 x 10Hz) in ipsi- and contralateral funiculi also evoked a slow IPSP mediated by noradrenaline acting via alpha 2-adrenergic receptors to increase a potassium conductance. The results provide insight into central mechanisms that contribute to the regulation of adrenomedullary catecholamine secretion.","abstract_html":"Sympathetic preganglionic neurons innervating the adrenal medulla (AD-SPN) regulate the release of adrenal catecholamines into the bloodstream. This research was undertaken to investigate the intrinsic properties and synaptic pathways characteristic of AD-SPN in neonatal rat spinal cord slice preparation. The presence of Lucifer Yellow from the patch pipette and Rhodamine-Dextran-Lysine from the adrenal medulla in the same neuron post recording identified AD-SPN. Active intrinsic properties revealed and characterised include: a potassium-mediated transient outward rectification present in 96% of AD-SPN and separable into a short 4-aminopyridine- and a long barium-sensitive component; a potassium-mediated sustained outward rectification revealed in TTx, activated positive to -50mV and blocked with quinine. These conductances contribute to the repolarising phase of the action potential. 89% of AD-SPN possessed potassium-mediated anomalous inward rectification. All AD-SPN displayed a high voltage-activated calcium spike that prolongs the action potential. The addition of internal caesium (140mM) revealed a low threshold spike mediated by T-type calcium channels that serve to facilitate burst firing. 75% of AD-SPN exhibited evidence of electrotonic coupling, indicated by characteristic oscillations in membrane potential and confirmed with dual recordings from electrotonically coupled AD-SPN. Electrotonic coupling promoted synchronous activity. An enhanced afterhyperpolarising potential facilitated transient termination of action potential firing forming bursts of activity. A role for calcium in the regulation of neuronal activity via action on electrotonic coupling was suggested by caffeine (10mM) decreasing, BAPTA-AM (15muM) and calcium free aCSF increasing the junctional conductance. Electrical stimulation of the descending fibres in both the ipsi- and contralateral funiculi evoked fast EPSPs in all AD-SPN that were mediated by both NMDA and non-NMDA receptors. A subpopulation of AD-SPN received fast IPSPs mediated by GABA acting via GABAA receptors. A train of stimuli (4 x 10Hz) in ipsi- and contralateral funiculi also evoked a slow IPSP mediated by noradrenaline acting via alpha 2-adrenergic receptors to increase a potassium conductance. The results provide insight into central mechanisms that contribute to the regulation of adrenomedullary catecholamine secretion.","abstract_has_math":false,"creators":["Wilson, Jennifer M. M."],"institution":"University of Ottawa (Canada)","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Renaud, Leo-P.,"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-03-23T13:06:34Z","date_published":"2009-03-23T13:06:34Z","updated_at":"2026-07-24T03:39:21Z","subjects":["Biology, Neuroscience."],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["Source: Dissertation Abstracts International, Volume: 64-01, Section: B, page: 0100.","9780612765078","http://dx.doi.org/10.20381/ruor-14793"],"render_values":[{"text":"Source: Dissertation Abstracts International, Volume: 64-01, Section: B, page: 0100.","href":null,"code":true},{"text":"9780612765078","href":null,"code":true},{"text":"http://dx.doi.org/10.20381/ruor-14793","href":"http://dx.doi.org/10.20381/ruor-14793","code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10393/6334","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Renaud, Leo-P.,"]},{"key":"dc:creator","label":"Author","values":["Wilson, Jennifer M. 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This research was undertaken to investigate the intrinsic properties and synaptic pathways characteristic of AD-SPN in neonatal rat spinal cord slice preparation. The presence of Lucifer Yellow from the patch pipette and Rhodamine-Dextran-Lysine from the adrenal medulla in the same neuron post recording identified AD-SPN. Active intrinsic properties revealed and characterised include: a potassium-mediated transient outward rectification present in 96% of AD-SPN and separable into a short 4-aminopyridine- and a long barium-sensitive component; a potassium-mediated sustained outward rectification revealed in TTx, activated positive to -50mV and blocked with quinine. These conductances contribute to the repolarising phase of the action potential. 89% of AD-SPN possessed potassium-mediated anomalous inward rectification. All AD-SPN displayed a high voltage-activated calcium spike that prolongs the action potential. The addition of internal caesium (140mM) revealed a low threshold spike mediated by T-type calcium channels that serve to facilitate burst firing. 75% of AD-SPN exhibited evidence of electrotonic coupling, indicated by characteristic oscillations in membrane potential and confirmed with dual recordings from electrotonically coupled AD-SPN. Electrotonic coupling promoted synchronous activity. An enhanced afterhyperpolarising potential facilitated transient termination of action potential firing forming bursts of activity. A role for calcium in the regulation of neuronal activity via action on electrotonic coupling was suggested by caffeine (10mM) decreasing, BAPTA-AM (15muM) and calcium free aCSF increasing the junctional conductance. Electrical stimulation of the descending fibres in both the ipsi- and contralateral funiculi evoked fast EPSPs in all AD-SPN that were mediated by both NMDA and non-NMDA receptors. A subpopulation of AD-SPN received fast IPSPs mediated by GABA acting via GABAA receptors. A train of stimuli (4 x 10Hz) in ipsi- and contralateral funiculi also evoked a slow IPSP mediated by noradrenaline acting via alpha 2-adrenergic receptors to increase a potassium conductance. The results provide insight into central mechanisms that contribute to the regulation of adrenomedullary catecholamine secretion."]},{"key":"dc:format","label":"Dc Format","values":["249 p.","application/pdf"]},{"key":"dc:title","label":"Title","values":["Mechanisms of neuronal integration in adrenomedullary sympathetic preganglionic neurons."]}]}],"canonical_facts":{"dc:contributor":["Renaud, Leo-P.,"],"dc:creator":["Wilson, Jennifer M. M."],"dc:date":["2009-03-23T13:06:34Z","2002"],"dc:description":["Sympathetic preganglionic neurons innervating the adrenal medulla (AD-SPN) regulate the release of adrenal catecholamines into the bloodstream. This research was undertaken to investigate the intrinsic properties and synaptic pathways characteristic of AD-SPN in neonatal rat spinal cord slice preparation. The presence of Lucifer Yellow from the patch pipette and Rhodamine-Dextran-Lysine from the adrenal medulla in the same neuron post recording identified AD-SPN. Active intrinsic properties revealed and characterised include: a potassium-mediated transient outward rectification present in 96% of AD-SPN and separable into a short 4-aminopyridine- and a long barium-sensitive component; a potassium-mediated sustained outward rectification revealed in TTx, activated positive to -50mV and blocked with quinine. These conductances contribute to the repolarising phase of the action potential. 89% of AD-SPN possessed potassium-mediated anomalous inward rectification. All AD-SPN displayed a high voltage-activated calcium spike that prolongs the action potential. The addition of internal caesium (140mM) revealed a low threshold spike mediated by T-type calcium channels that serve to facilitate burst firing. 75% of AD-SPN exhibited evidence of electrotonic coupling, indicated by characteristic oscillations in membrane potential and confirmed with dual recordings from electrotonically coupled AD-SPN. Electrotonic coupling promoted synchronous activity. An enhanced afterhyperpolarising potential facilitated transient termination of action potential firing forming bursts of activity. A role for calcium in the regulation of neuronal activity via action on electrotonic coupling was suggested by caffeine (10mM) decreasing, BAPTA-AM (15muM) and calcium free aCSF increasing the junctional conductance. Electrical stimulation of the descending fibres in both the ipsi- and contralateral funiculi evoked fast EPSPs in all AD-SPN that were mediated by both NMDA and non-NMDA receptors. A subpopulation of AD-SPN received fast IPSPs mediated by GABA acting via GABAA receptors. A train of stimuli (4 x 10Hz) in ipsi- and contralateral funiculi also evoked a slow IPSP mediated by noradrenaline acting via alpha 2-adrenergic receptors to increase a potassium conductance. The results provide insight into central mechanisms that contribute to the regulation of adrenomedullary catecholamine secretion."],"dc:format":["249 p.","application/pdf"],"dc:identifier":["Source: Dissertation Abstracts International, Volume: 64-01, Section: B, page: 0100.","9780612765078","http://hdl.handle.net/10393/6334","http://dx.doi.org/10.20381/ruor-14793"],"dc:publisher":["University of Ottawa (Canada)"],"dc:subject":["Biology, Neuroscience."],"dc:title":["Mechanisms of neuronal integration in adrenomedullary sympathetic preganglionic neurons."],"dc:type":["Thesis"]},"updated_at":"2026-07-24T03:39:21Z"}