Serotonin transporter deficiency alters socioemotional ultrasonic communication in rats

Abstract

It has been widely established that serotonin plays important role in the regulation of emotional and social behaviour. Rodents with a genetic deletion of the serotonin reuptake transporter (SERT) are used as a model to study lifelong consequences of increased extracellular 5‐HT levels due to its impaired reuptake. SERT knock-out (SERT-KO) mice and rats consistently showed anxiety-like symptoms and social deficits. Nevertheless, the impact of SERT deletion on socioemotional ultrasonic communication has not been addressed. Here we investigated the impact of lifelong serotonin abundance on ultrasonic vocalisation accompanying social interactions and open field exploration in rats. SERT-KO rats displayed reduced overall duration of social contacts, but increased time spent on following the conspecific. The altered pattern of social behaviour in SERT-KO rats was accompanied by the structural changes in ultrasonic vocalisations, as they differed from their controls in distribution of call categories. Moreover, SERT deletion resulted in anxiety-like behaviours assessed in the open field test. Their anxious phenotype resulted in a lower tendency to emit appetitive 50-kHz calls during novelty exploration. The present study demonstrates that genetic deletion of SERT not only leads to the deficits in social interaction and increased anxiety but also affects ultrasonic communication.

Enrichment Environment Positively Influences Depression- and Anxiety-Like Behavior in Serotonin Transporter Knockout Rats through the Modulation of Neuroplasticity, Spine, and GABAergic Markers

“…In the sucrose consumption test, we found a reduced preference of the sucrose solution relative to plain water, confirming the anhedonic phenotype of this animal model [ 21 ]. Similarly, in line with the literature results [ 21 , 49 ], we found anxiety-like behavior in SERT −/− rats tested in the EPM test. Interestingly, one month of EE normalized these anxiety and depressive-like symptoms in SERT −/− rats.…”

Serotonin transporter knockout in rats modulates category learning

“…The present findings may explain other phenotypes observed in the 5-HTT KO rats, such as reduced social interaction 40 , lower ultrasonic communication during food exploration 41 and repetitive behavior 12 , which are characteristic of ASD-like behaviors. More specifically, KO rats may have a reduced tendency to explore novel stimuli in their environment, and instead exploit stimuli they are familiar with, such as themselves (leading to less social interaction), previous food location and known objects, respectively.…”

Implication of 5-HT7 receptor in prefrontal circuit assembly and detrimental emotional effects of SSRIs during development

“…Exposure to a variety of SSRIs including FLX during the postnatal period has been repeatedly found to cause anxiety and depressive-like phenotypes later in life [ 20 , 56 – 58 ]. Similarly, genetic models interfering with SERT function such as SERT-KO rodents display paradoxical depressive-like behaviors that can be explained by an increased 5-HT signaling during the first postnatal weeks [ 8 , 59 ]. Pharmacological approaches indicated a partial role of the excess of activation of the 5-HTR1A [ 8 ] and 5-HTR2A receptors [ 58 ] in these effects.…”