Journal article
Spatiotemporal control of noradrenaline-dependent synaptic transmission in mouse dorsal raphe serotonin neurons
The Journal of neuroscience, Vol.42(6), pp.968-979
12/13/2021
DOI: 10.1523/JNEUROSCI.1176-21.2021
PMID: 34921047
Abstract
Activity of dorsal raphe neurons is controlled by noradrenaline afferents. In this brain region, noradrenaline activates Gα
-coupled α1-adrenergic receptors (α1-A
), causing action potential firing and serotonin release.
, electrical stimulation elicits vesicular noradrenaline release and subsequent activation of α1-A
to produce an excitatory postsynaptic current (α1-A
-EPSC). The duration of the α1-A
-EPSC (∼27 s) is much longer than that of most other synaptic currents, but the factors that govern the spatiotemporal dynamics of α1-A
are poorly understood. Using an acute brain slice preparation from adult male and female mice and electrophysiological recordings from dorsal raphe neurons, we found that the time-course of the α1-A
-EPSC was slow, but highly consistent within individual serotonin neurons. The amount of noradrenaline released influenced the amplitude of the α1-A
-EPSC without altering the time constant of decay suggesting that once released, extracellular noradrenaline was cleared efficiently. Reuptake of noradrenaline via noradrenaline transporters was a primary means of terminating the α1-A
-EPSC, with little evidence for extrasynaptic diffusion of noradrenaline unless transporter-dependent reuptake was impaired. Taken together, the results demonstrate that despite slow intrinsic signaling kinetics, noradrenaline-dependent synaptic transmission in the dorsal raphe is temporally and spatially controlled and noradrenaline transporters are critical regulators of serotonin neuron excitability. Given the functionally distinct types of neurons intermingled in the dorsal raphe nucleus and the unique roles of these neural circuits in physiological responses, transporters may preserve independence of each synapse to encode a long-lasting but discrete signal.
The dorsal raphe nucleus is the predominant source of serotonin in the brain and is controlled by another monoamine, noradrenaline. In this brain region, noradrenaline activates G protein-coupled α1-adrenergic receptors causing action potential firing and serotonin release. In spite of high interest in pharmacotherapies to enhance serotonin signaling, the factors that govern noradrenaline α1-A
signaling have received little attention. Here we show using mouse brain slices that the time-course of α1-A
signaling is slow, persisting for tens of seconds. Despite slow intrinsic signaling kinetics, noradrenaline-dependent synaptic transmission in the dorsal raphe is controlled temporally and spatially by efficient noradrenaline transporter-dependent clearance extracellular noradrenaline. Thus, noradrenaline transporters are critical regulators of serotonin neuron excitability.
Details
- Title: Subtitle
- Spatiotemporal control of noradrenaline-dependent synaptic transmission in mouse dorsal raphe serotonin neurons
- Creators
- Jacqueline K Khamma - Department of Molecular Physiology & Biophysics, Carver College of Medicine, University of Iowa; Iowa City, Iowa, 52242, USADaniel S Copeland - Department of Molecular Physiology & Biophysics, Carver College of Medicine, University of Iowa; Iowa City, Iowa, 52242, USAHolly S Hake - National Institute on Drug AbuseStephanie C Gantz - Department of Molecular Physiology & Biophysics, Carver College of Medicine, University of Iowa; Iowa City, Iowa, 52242, USA Stephanie-Gantz@uiowa.edu
- Resource Type
- Journal article
- Publication Details
- The Journal of neuroscience, Vol.42(6), pp.968-979
- DOI
- 10.1523/JNEUROSCI.1176-21.2021
- PMID
- 34921047
- NLM abbreviation
- J Neurosci
- ISSN
- 0270-6474
- eISSN
- 1529-2401
- Grant note
- DOI: 10.13039/100008893, name: University of Iowa; DOI: 10.13039/100000026, name: HHS | NIH | National Institute on Drug Abuse
- Language
- English
- Date published
- 12/13/2021
- Academic Unit
- Molecular Physiology and Biophysics; Iowa Neuroscience Institute
- Record Identifier
- 9984203957702771
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