©2011 American College of Neuropsychopharmacology
"Severe Serotonin Depletion after Conditional Deletion of the Vesicular Monoamine Transporter 2 Gene in Serotonin Neurons: Neural and Behavioural Consequences"
Summary: In an aversive ultrasound-induced defense paradigm, mice displayed a major increase in “wild” escape-like behaviours. Study Keywords include depression; anxiety; defense behaviours. (Page 1)
Mice were tested for their innate fear reactions to a train of ultrasonic stimuli/us. Animals were placed one per cage for at least 1 week before testing. In brief, 100 ms frequency sweeps between 17 and 20 kHz, 85 dB, alternately ON 2 seconds and then OFF 2 seconds for 1 min were delivered into the home cage after a 3-min baseline period. Flight reactions triggered during ON periods were measured as the number of running events from one side of the cage to the other followed by behavioural arrest. The percentage time “freezing” to the ultrasonic stimuli was quantified by sampling events of complete immobility (except respiration) every 4 seconds during the OFF period. These defense behaviours were measured from a video file by an observer unaware of mouse genotype. (Page 3)
This diagram shows the Inverse relationship between brain tissue levels of 5-HT and aversive ultrasound-induced flight behaviours in mice. (a) There was an enhancement of flight behaviours in reaction to the aversive ultrasound (1 min fast sweep 17–20 kHz, 85 dB) in mice compared with control mice, which was reversed by a chronic treatment with pargyline. (Page 9)
Reference: ©Neuropsychopharmacology (2011)
Nicolas Narboux-Nême, Corinne Sagné, Stephane Doly, Silvina L Diaz, Cédric B P Martin, + et al.
Neuropsychopharmacology 36, 2538-2550 doi:10.1038/npp.2011.142