Journal article
Oxytocin Enhances Cranial Visceral Afferent Synaptic Transmission to the Solitary Tract Nucleus
The Journal of neuroscience, Vol.28(45), pp.11731-11740
11/05/2008
Handle:
https://hdl.handle.net/2376/113707
PMCID: PMC2585803
PMID: 18987209
Abstract
Cranial visceral afferents travel via the solitary tract (ST) to contact neurons within the ST nucleus (NTS) and activate homeostatic reflexes. Hypothalamic projections from the paraventricular nucleus (PVN) release oxytocin (OT) to modulate visceral afferent communication with NTS neurons. However, the cellular mechanisms through which OT acts are poorly understood. Here, we electrophysiologically identified second-order NTS neurons in horizontal brainstem slices by their low-jitter, ST-evoked glutamatergic EPSCs. OT increased the frequency of miniature EPSCs in half of the NTS second-order neurons (13/24) but did not alter event kinetics or amplitudes. These actions were blocked by a selective OT receptor antagonist. OT increased the amplitude of ST-evoked EPSCs with no effect on event kinetics. Variance–mean analysis of ST-evoked EPSCs indicated OT selectively increased the release probability of glutamate from the ST afferent terminals. In OT-sensitive neurons, OT evoked an inward holding current and increased input resistance. The OT-sensitive current reversed at the K
+
equilibrium potential. In
in vivo
studies, NTS neurons excited by vagal cardiopulmonary afferents were juxtacellularly labeled with Neurobiotin and sections were stained to show filled neurons and OT-immunoreactive axons. Half of these physiologically characterized neurons (5/10) showed close appositions by OT fibers consistent with synaptic contacts. Electron microscopy of medial NTS found immunoreactive OT within synaptic boutons. Together, these findings suggest that OT released from PVN axons acts on a subset of second-order neurons within medial NTS to enhance visceral afferent transmission via presynaptic and postsynaptic mechanisms.
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Details
- Title
- Oxytocin Enhances Cranial Visceral Afferent Synaptic Transmission to the Solitary Tract Nucleus
- Creators
- James H Peters - Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098Stuart J McDougall - Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098Daniel O Kellett - Department of Physiology, Royal Free and University College Medical School, University College London, London WC1E 6BT, United Kingdom, andDavid Jordan - Department of Physiology, Royal Free and University College Medical School, University College London, London WC1E 6BT, United Kingdom, andIda J Llewellyn-Smith - Cardiovascular Medicine and Centre for Neuroscience, Flinders University, Bedford Park, South Australia 5042, AustraliaMichael C Andresen - Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098
- Publication Details
- The Journal of neuroscience, Vol.28(45), pp.11731-11740
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Publisher
- Society for Neuroscience
- Identifiers
- 99900547408701842
- Language
- English
- Resource Type
- Journal article