Neuronal localization of the 5-HT2 receptor family in the amygdaloid complex

Bombardi, Cristiano

doi:10.3389/fphar.2014.00068

Cited by 40 publications

(27 citation statements)

References 100 publications

(176 reference statements)

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“…Fear conditioning is known to be a model of emotional learning in which amygdala circuits play an important role (see references in Bombardi, 2014). The amygdala receives substantial serotoninergic innervation originating mainly from the dorsal raphe nucleus and, to a lesser extent, from the median raphe nucleus (Pralong et al, 2002;Hensler, 2006;Asan et al, 2013).…”

Section: G Serotonin 5-hydroxytryptamine 2a Receptor Expression In Tmentioning

confidence: 99%

Psychedelics

2016

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Section: G Serotonin 5-hydroxytryptamine 2a Receptor Expression In Tmentioning

confidence: 99%

Psychedelics

2016

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“…These studies support the view that activation of BLA 5-HT1a receptors reduces Arc expression in pyramidal cells and thereby disrupts the formation of a defeat-related fear memory. 5-HT2c receptors are localized to both glutamatergic pyramidal cells and GABAergic interneurons in the BLA (Bombardi, 2014; Clemett et al, 2000). Activation of 5-HT2c receptors in the BLA facilitates the acquisition of inhibition avoidance in the elevated T-maze and increases anxiety in the light-dark transition test (Vicente & Zangrossi, 2014).…”

Section: Discussionmentioning

confidence: 99%

Activation of 5-HT2a receptors in the basolateral amygdala promotes defeat-induced anxiety and the acquisition of conditioned defeat in Syrian hamsters

et al. 2015

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Conditioned defeat is a model in Syrian hamsters (Mesocricetus auratus) in which normal territorial aggression is replaced by increased submissive and defensive behavior following acute social defeat. The conditioned defeat response involves both a fear-related memory for a specific opponent as well as anxiety-like behavior indicated by avoidance of novel conspecifics. We have previously shown that systemic injection of a 5-HT2a receptor antagonist reduces the acquisition of conditioned defeat. Because neural activity in the basolateral amygdala (BLA) is critical for the acquisition of conditioned defeat and BLA 5-HT2a receptors can modulate anxiety but have a limited effect on emotional memories, we investigated whether 5-HT2a receptor modulation alters defeat-induced anxiety but not defeat-related memories. We injected the 5-HT2a receptor antagonist MDL 11,939 (0 mM, 1.7 mM or 17 mM) or the 5-HT2a receptor agonist TCB-2 (0 mM, 8 mM or 80 mM) into the BLA prior to social defeat. We found that injection of MDL 11,939 into the BLA impaired acquisition of the conditioned defeat response and blocked defeat-induced anxiety in the open field, but did not significantly impair avoidance of former opponents in the Y-maze. Furthermore, we found that injection of TCB-2 into the BLA increased the acquisition of conditioned defeat and increased anxiety-like behavior in the open field, but did not alter avoidance of former opponents. Our data suggest that 5-HT2a receptor signaling in the BLA is both necessary and sufficient for the development of conditioned defeat, likely via modulation of defeat-induced anxiety.

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“…Serotonergic fibers that originate in the dorsal and medial raphe nuclei regulate amygdalar activity by stimulating the 5-HT2 receptor family. However, the precise role of the 5-HT2A vs. the 5-HT2C receptor is not known (Bombardi, 2014). Moreover, the role of the 5-HT2B receptor has rarely been studied.…”

Section: The Monoamine Hypothesismentioning

confidence: 99%

Circuits Regulating Pleasure and Happiness—Mechanisms of Depression

Loonen

Ivanova

2016

Front. Hum. Neurosci.

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According to our model of the regulation of appetitive-searching vs. distress-avoiding behaviors, the motivation to display these essential conducts is regulated by two parallel cortico-striato-thalamo-cortical, re-entry circuits, including the core and the shell parts of the nucleus accumbens, respectively. An entire series of basal ganglia, running from the caudate nucleus on one side, to the centromedial amygdala on the other side, controls the intensity of these reward-seeking and misery-fleeing behaviors by stimulating the activity of the (pre)frontal and limbic cortices. Hyperactive motivation to display behavior that potentially results in reward induces feelings of hankering (relief leads to pleasure). Hyperactive motivation to exhibit behavior related to avoidance of misery results in dysphoria (relief leads to happiness). These two systems collaborate in a reciprocal fashion. In clinical depression, a mismatch exists between the activities of these two circuits: the balance is shifted to the misery-avoiding side. Five theories have been developed to explain the mechanism of depressive mood disorders, including the monoamine, biorhythm, neuro-endocrine, neuro-immune, and kindling/neuroplasticity theories. This paper describes these theories in relationship to the model (described above) of the regulation of reward-seeking vs. misery-avoiding behaviors. Chronic stress that leads to structural changes may induce the mismatch between the two systems. This mismatch leads to lack of pleasure, low energy, and indecisiveness, on one hand, and dysphoria, continuous worrying, and negative expectations on the other hand. The neuroplastic effects of monoamines, cortisol, and cytokines may mediate the induction of these structural alterations. Long-term exposure to stressful situations (particularly experienced during childhood) may lead to increased susceptibility for developing this condition. This hypothesis opens up the possibility of treating depression with psychotherapy. Genetic and other biological factors (toxic, infectious, or traumatic) may increase sensitivity to the induction of relevant neuroplastic changes. Reversal or compensation of these neuroplastic adjustments may explain the effects of biological therapies in treating depression.

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Neuronal localization of the 5-HT2 receptor family in the amygdaloid complex

Cited by 40 publications

References 100 publications

Psychedelics

Psychedelics

Activation of 5-HT2a receptors in the basolateral amygdala promotes defeat-induced anxiety and the acquisition of conditioned defeat in Syrian hamsters

Circuits Regulating Pleasure and Happiness—Mechanisms of Depression

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