ABSTRACT
Stress induces an exaggerated emotional response to a subsequent novel aversive stimulus (Emotional sensitization). The induction of Cdk5 in septum and hippocampus by exposure to an aversive event has been previously reported. The aim of this work was to determine whether Cdk5 and/or its activator p35 would be implicated in the emotional sequelae provoked by a prior restraint event.
The experiments were conducted in male Wistar rats, male p35 knock out mices (p35-/-) and wild type mices (p35+/+). Rats were restrained during one hour and immediately decapitated for the determination of the proteins levels. Another group was evaluated behaviorally in the elevated plus maze (EPM) 24 hs after stress exposure in the case of rats and 30 min later in the case of mice. A cannula was implanted in the lateral septum in a group of rats, for the local administration of olomucine (Cdk5 inhibitor), 15 min before restraint.
Results
Restraint produced an increase of Cdk5 and p35 levels in dorsal and ventral portions, but not intermediate portion, of the lateral septum (by inmunohistochesmitry and Western Blot). Moreover, the stress experience decreased the percentage of time in the open arms (OA) in rats and in p35+/+ but not in p35-/- mice.
Conclusion
Stress increases Cdk5 and p35 expression in dorsal and ventral portions of the lateral septum, which are implicated in the processing of emotional information. This increase could be implicated in the emotional sensitization process induced by stress.
