Abdominal vagal deafferentation alters affective behaviors in rats

• Published in: Journal of affective disorders 2019-06, Vol.252, p.404-412
• Main Authors: Klarer, Melanie, Weber-Stadlbauer, Ulrike, Arnold, Myrtha, Langhans, Wolfgang, Meyer, Urs
• Format: Article
• Language: English
• Subjects: Abdomen - innervation; Affect; Affective behavior; Afferent Pathways; Anhedonia; Animals; Depression; Disease Models, Animal; Forced swim test; Male; Mood Disorders - physiopathology; Mood Disorders - therapy; Rats; Rats, Sprague-Dawley; Sucrose preference; Swimming; Vagus nerve; Vagus Nerve - physiology; Vagus Nerve Stimulation
• ISSN: 0165-0327; 1573-2517
• DOI: 10.1016/j.jad.2019.04.015

•Abdominal vagal deafferentation reduces novelty-induced exploratory activity.•Abdominal vagal deafferentation increases the latency in novelty-suppressed eating.•Abdominal vagal deafferentation induces anhedonia in the sucrose preference test.•Abdominal vagal deafferentation does not affect social approach behavior.•Abdominal vagal deafferentation increases immobility in the forced swim test. There is growing evidence for a role of abnormal gut-brain signaling in disorders involving altered mood and affect, including depression. Studies using vagus nerve stimulation (VNS) suggest that the disruption of vagal afferent signaling may contribute to these abnormalities. To test this hypothesis, we used a rat model of subdiaphragmatic vagal deafferentation (SDA), the most complete and selective vagal deafferentation method existing to date, to study the consequences of complete disconnection of abdominal vagal afferents on affective behaviors. SDA- and Sham-operated male rats were subjected to several tests that are commonly used in preclinical rodent models to assess the presence of anhedonic behavior, namely the novel object-induced exploration test, the novelty-suppressed eating test, and the sucrose preference test. In addition, we compared SDA and Sham rats in a social interaction test and the forced swim test to assess sociability and behavioral despair, respectively. Compared to Sham controls, SDA rats consistently displayed signs of anhedonic behavior in all test settings used. SDA rats also showed increased immobility and reduced swimming in the forced swim test, whereas they did not differ from Sham controls with regards to social approach behavior. This study was conducted in male rats only. Hence, possible sex-specific effects of SDA on affective behaviors remained unexamined. Our findings demonstrate that hedonic behavior and behavioral despair are subject to visceral modulation through abdominal vagal afferents. These data are compatible with preclinical models and clinical trials showing beneficial effects of VNS on depression-like and affective behaviors.