Transmission to interneurons is via slow excitatory synaptic potentials mediated by P2Y(1) receptors during descending inhibition in guinea-pig ileum
| Autor: | Darren J. McMillan, Joel C. Bornstein, Rachel M Gwynne, Peter D. J. Thornton |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Male
Anatomy and Physiology Digestive Physiology Neuromuscular transmission lcsh:Medicine Nicotinic Antagonists Receptors Nicotinic Synaptic Transmission Digestive Anatomy chemistry.chemical_compound Receptors Purinergic P2Y1 0302 clinical medicine Postsynaptic potential Serotonin 5-HT3 Receptor Antagonists lcsh:Science 0303 health sciences Multidisciplinary Gastrointestinal Motility Disorders Anatomy Synaptic Potentials Cell biology Adenosine Diphosphate Electrophysiology Neurology Pyridoxal Phosphate Excitatory postsynaptic potential Medicine Small Intestine Female Research Article Drugs and Devices Guinea Pigs Gastroenterology and Hepatology Biology P2 receptor Neurotransmission Inhibitory postsynaptic potential Autonomic Nervous System Neurological System 03 medical and health sciences Neuropharmacology Ileum Interneurons Reflex Peripheral Nervous System Animals PPADS 030304 developmental biology Digestive Functions lcsh:R Excitatory Postsynaptic Potentials Metabotropic receptor chemistry nervous system Synapses Purinergic P2Y Receptor Antagonists lcsh:Q Receptors Serotonin 5-HT3 Digestive System 030217 neurology & neurosurgery |
| Zdroj: | PLoS ONE, Vol 8, Iss 2, p e40840 (2013) PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | BACKGROUND: The nature of synaptic transmission at functionally distinct synapses in intestinal reflex pathways has not been fully identified. In this study, we investigated whether transmission between interneurons in the descending inhibitory pathway is mediated by a purine acting at P2Y receptors to produce slow excitatory synaptic potentials (EPSPs). METHODOLOGY/PRINCIPAL FINDINGS: Myenteric neurons from guinea-pig ileum in vitro were impaled with intracellular microelectrodes. Responses to distension 15 mm oral to the recording site, in a separately perfused stimulation chamber and to electrical stimulation of local nerve trunks were recorded. A subset of neurons, previously identified as nitric oxide synthase immunoreactive descending interneurons, responded to both stimuli with slow EPSPs that were reversibly abolished by a high concentration of PPADS (30 μM, P2 receptor antagonist). When added to the central chamber of a three chambered organ bath, PPADS concentration-dependently depressed transmission through that chamber of descending inhibitory reflexes, measured as inhibitory junction potentials in the circular muscle of the anal chamber. Reflexes evoked by distension in the central chamber were unaffected. A similar depression of transmission was seen when the specific P2Y(1) receptor antagonist MRS 2179 (10 μM) was in the central chamber. Blocking either nicotinic receptors (hexamethonium 200 μM) or 5-HT(3) receptors (granisetron 1 μM) together with P2 receptors had no greater effect than blocking P2 receptors alone. CONCLUSIONS/SIGNIFICANCE: Slow EPSPs mediated by P2Y(1) receptors, play a primary role in transmission between descending interneurons of the inhibitory reflexes in the guinea-pig ileum. This is the first demonstration for a primary role of excitatory metabotropic receptors in physiological transmission at a functionally identified synapse. |
| Databáze: | OpenAIRE |
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