Loss of Adult 5-HT1A Autoreceptors Results in a Paradoxical Anxiogenic Response to Antidepressant Treatment.

Selective serotonin (5-HT) reuptake inhibitors (SSRIs) are first-line antidepressants but require several weeks to elicit their actions. Chronic SSRI treatment induces desensitization of 5-HT1A autoreceptors to enhance 5-HT neurotransmission. Mice (both sexes) with gene deletion of 5-HT1A autoreceptors in adult 5-HT neurons () were tested for response to SSRIs.

PGE EP receptor inhibits vasopressin-dependent water reabsorption and sodium transport in mouse collecting duct.

PGE2 regulates glomerular hemodynamics, renin secretion, and tubular transport. This study examined the contribution of PGE2 EP1 receptors to sodium and water homeostasis. Male EP1-/- mice were bred with hypertensive TTRhRen mice (Htn) to evaluate blood pressure and kidney function at 8 weeks of age in four groups: wildtype (WT), EP1-/-, Htn, HtnEP1-/-.

Abrogated Freud-1/Cc2d1a Repression of 5-HT1A Autoreceptors Induces Fluoxetine-Resistant Anxiety/Depression-Like Behavior.

Freud-1/Cc2d1a represses the gene transcription of serotonin-1A (5-HT1A) autoreceptors, which negatively regulate 5-HT tone. To test the role of Freud-1 , we generated mice with adulthood conditional knock-out of Freud-1 in 5-HT neurons (). In mice, 5-HT1A autoreceptor protein, binding and hypothermia response were increased, with reduced 5-HT content and neuronal activity in the dorsal raphe.

Sex-dependent adaptive changes in serotonin-1A autoreceptor function and anxiety in Deaf1-deficient mice.

The C (-1019) G rs6295 promoter polymorphism of the serotonin-1A (5-HT1A) receptor gene is associated with major depression in several but not all studies, suggesting that compensatory mechanisms mediate resilience. The rs6295 risk allele prevents binding of the repressor Deaf1 increasing 5-HT1A receptor gene transcription, and the Deaf1-/- mouse model shows an increase in 5-HT1A autoreceptor expression. In this study, Deaf1-/- mice bred on a mixed C57BL6-BALB/c background were compared to wild-type littermates for 5-HT1A autoreceptor function and behavior in males and females.

Target-specific modulation of the descending prefrontal cortex inputs to the dorsal raphe nucleus by cannabinoids.

Serotonin (5-HT) neurons located in the raphe nuclei modulate a wide range of behaviors by means of an expansive innervation pattern. In turn, the raphe receives a vast array of synaptic inputs, and a remaining challenge lies in understanding how these individual inputs are organized, processed, and modulated in this nucleus to contribute ultimately to the core coding features of 5-HT neurons. The details of the long-range, top-down control exerted by the medial prefrontal cortex (mPFC) in the dorsal raphe nucleus (DRN) are of particular interest, in part, because of its purported role in stress processing and mood regulation.

Time-dependent modulation of glutamate synapses onto 5-HT neurons by antidepressant treatment.

Antidepressants, including the selective serotonin reuptake inhibitors (SSRIs), are thought to exert their clinical effects by enhancing serotonin (5-HT) transmission. However, animal studies show that the full magnitude of this enhancement is reached only following prolonged treatments with SSRIs, consistent with the well-described therapeutic delay of this class of medications. Thus, the clinical efficacy of SSRIs most likely does not emerge from their acute pharmacological actions, but rather indirectly from cellular alterations that develop over the course of a sustained treatment.