Differential modulation of CA1 impulse flow by endogenous serotonin along the hippocampal longitudinal axis.
Boris Mlinar, Renato Corradetti
Hippocampus March 2018 DOI: 10.1002/hipo.22825 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | In vitro electrophysiological study Longitudinal Peer reviewed |
|---|---|
| Population | Transversal hippocampal slices from rat |
| Intervention | MDMA |
| Measures | evoked population spikes in the CA1 area |
| Topics | MDMA Serotonin |
| Keywords | 5-ht1a receptor Noradrenaline Population spike Rat rrid |
| Key points | Endogenous serotonin, released by MDMA, differentially modulates CA1 population spikes along the dorsoventral axis: it decreases spike amplitude in dorsal hippocampus and increases it in ventral hippocampus, while noradrenaline increases amplitude uniformly. The gradient requires 5-HT1A receptor activation, as blockade prevents the inhibitory component and the gradient. The authors propose this dorsoventral shift may encode the emotional salience of hippocampal signals. |
Abstract
The hippocampus is functionally differentiated along its longitudinal axis, with the dorsal and ventral segments preferentially involved in cognitive and emotional processing, respectively. Serotonergic modulation of hippocampal function has been extensively studied, but its relation to the dorsoventral axis has remained largely unknown. To examine the modulation of hippocampal output along the dorsoventral axis by endogenous serotonin (5-HT) we compared the effect of the 5-HT/noradrenaline (NA)-releaser, 3,4-methylenedioxymethamphetamine (MDMA), in transversal slices encompassing the entire rat hippocampus. Co-release of 5-HT and NA by MDMA resulted in a gradient of effects on evoked population spikes in the CA1 area along the dorsoventral axis of the hippocampus. Selective 5-HT release decreased population spike amplitude in slices from dorsal hippocampus, whereas an increase was produced in the ventral hippocampus, indicating differential modulation of CA1 impulse flow along the dorsoventral axis by endogenous 5-HT. Selective NA release increased population spike amplitude with no gradient indicating facilitatory effect of endogenous NA along the entire dorsoventral axis. Blockade of 5-HT1A receptors prevented the inhibitory component of MDMA action and the emergence of the gradient, indicating that activation of 5-HT1A receptors is required for differential modulation of CA1 impulse flow by endogenous 5-HT. These findings suggest that a dorsoventral shift in CA1 output level may represent an integral component of 5-HT action on hippocampal information processing. Given the preferential role of ventral hippocampus in emotional and anxiety-related behavior, it can be proposed that serotonin tone encodes the emotional salience of the signal processed by hippocampus.
Comparable studies
Other preclinical and animal studies on serotonin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin induces rapid and persistent growth of dendritic spines in frontal cortex in vivo Mice | 2021 | Observational cohort | |
| Neurotoxicity of the psychedelic amphetamine, methylenedioxymethamphetamine. Rats (implied by typical neurochemical study context) | 1987 | Experimental study | |
| Psychedelics promote neuroplasticity through the activation of intracellular 5-HT2A receptors In vitro and in vivo (rodent) models | 2023 | Experimental study | |
| 3,4-Methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine destroy serotonin terminals in rat brain: quantification of neurodegeneration by measurement of [3H]paroxetine-labeled serotonin uptake sites. Rat brain | 1987 | Animal experiment | |
| Comparison of the monoamine transporters from human and mouse in their sensitivities to psychostimulant drugs Human and mouse dopamine, norepinephrine, and serotonin transporters expressed in cells | 2006 | In vitro laboratory study |
Citations in the library
Cites 2
- Endogenous serotonin facilitates hippocampal long-term potentiation at CA3/CA1 synapses. Journal of Neural Transmission February 2015
- Interactions of methylenedioxymethamphetamine with monoamine transmitter release mechanisms in rat brain slices. Naunyn-Schmiedeberg's Archives of Pharmacology March 1, 1993