» Articles » PMID: 27556938

Serotonin Engages an Anxiety and Fear-promoting Circuit in the Extended Amygdala

Abstract

Serotonin (also known as 5-hydroxytryptamine (5-HT)) is a neurotransmitter that has an essential role in the regulation of emotion. However, the precise circuits have not yet been defined through which aversive states are orchestrated by 5-HT. Here we show that 5-HT from the dorsal raphe nucleus (5-HT) enhances fear and anxiety and activates a subpopulation of corticotropin-releasing factor (CRF) neurons in the bed nucleus of the stria terminalis (CRF) in mice. Specifically, 5-HT projections to the BNST, via actions at 5-HT receptors (5-HTRs), engage a CRF inhibitory microcircuit that silences anxiolytic BNST outputs to the ventral tegmental area and lateral hypothalamus. Furthermore, we demonstrate that this CRF inhibitory circuit underlies aversive behaviour following acute exposure to selective serotonin reuptake inhibitors (SSRIs). This early aversive effect is mediated via the corticotrophin-releasing factor type 1 receptor (CRFR, also known as CRHR1), given that CRFR antagonism is sufficient to prevent acute SSRI-induced enhancements in aversive learning. These results reveal an essential 5-HT→CRF circuit governing fear and anxiety, and provide a potential mechanistic explanation for the clinical observation of early adverse events to SSRI treatment in some patients with anxiety disorders.

Citing Articles

Dorsal raphe GABA-ergic neurons regulate the susceptibility to social transfer of pain in mice.

Ai L, Han Y, Ge T, Sha S, Zhai X, Ji R Acta Pharmacol Sin. 2025; .

PMID: 40011629 DOI: 10.1038/s41401-025-01494-x.


Deciphering the Functions of Raphe-Hippocampal Serotonergic and Glutamatergic Circuits and Their Deficits in Alzheimer's Disease.

Yu W, Zhang R, Zhang A, Mei Y Int J Mol Sci. 2025; 26(3).

PMID: 39941002 PMC: 11818420. DOI: 10.3390/ijms26031234.


Monoamine neurochemistry, behavior, and microhabitat contribute to male coquí frog modes: silent, territorial, and paternal.

Eyck G, Regen E, Ten Eyck S, Korzan W, Summers C J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2025; .

PMID: 39909908 DOI: 10.1007/s00359-025-01732-x.


Exploring the effects of adolescent social isolation stress on the serotonin system and ethanol-motivated behaviors.

McElroy B, Li C, McCloskey N, Alberici A, Kirby L Psychopharmacology (Berl). 2025; 242(4):763-781.

PMID: 39903245 PMC: 11890253. DOI: 10.1007/s00213-025-06749-3.


Sports preferences in children and adolescents in psychiatric care-evaluation of a new questionnaire.

Breido F, Stumm S, Jenetzky E, Huss M Front Child Adolesc Psychiatry. 2025; 3():1354595.

PMID: 39816576 PMC: 11732098. DOI: 10.3389/frcha.2024.1354595.


References
1.
Fenno L, Mattis J, Ramakrishnan C, Hyun M, Lee S, He M . Targeting cells with single vectors using multiple-feature Boolean logic. Nat Methods. 2014; 11(7):763-72. PMC: 4085277. DOI: 10.1038/nmeth.2996. View

2.
Hefner K, Whittle N, Juhasz J, Norcross M, Karlsson R, Saksida L . Impaired fear extinction learning and cortico-amygdala circuit abnormalities in a common genetic mouse strain. J Neurosci. 2008; 28(32):8074-85. PMC: 2547848. DOI: 10.1523/JNEUROSCI.4904-07.2008. View

3.
Jennings J, Sparta D, Stamatakis A, Ung R, Pleil K, Kash T . Distinct extended amygdala circuits for divergent motivational states. Nature. 2013; 496(7444):224-8. PMC: 3778934. DOI: 10.1038/nature12041. View

4.
Liu J, Garza J, Bronner J, Kim C, Zhang W, Lu X . Acute administration of leptin produces anxiolytic-like effects: a comparison with fluoxetine. Psychopharmacology (Berl). 2009; 207(4):535-45. PMC: 4057895. DOI: 10.1007/s00213-009-1684-3. View

5.
Armbruster B, Li X, Pausch M, Herlitze S, Roth B . Evolving the lock to fit the key to create a family of G protein-coupled receptors potently activated by an inert ligand. Proc Natl Acad Sci U S A. 2007; 104(12):5163-8. PMC: 1829280. DOI: 10.1073/pnas.0700293104. View