title: Repeated amphetamine injections alter behavior and induce a delayed behavioral sensitization modulated by reactivity to novelty: Similarities and differences with trauma consequences.
abstract: Supporting our hypothesis of common biological bases for post-traumatic stress disorder (PTSD) and addiction, we recently reported that rats exposed to a single prolonged stress (SPS), a PTSD model, develop a delayed behavioral sensitization of the noradrenergic system, similar to that observed in mice after four repeated drug administrations. However, sensitization after trauma was modulated by reactivity to novelty, and this aspect that had not been explored in the addiction model. The first aim of the paper was thus to investigate the influence of reactivity to novelty on delayed behavioral sensitization in rats after four repeated amphetamine injections. Injections were either distributed over 4 days, as conducted in mouse models of addiction, or massed during a single session, reproducing SPS conditions. The second aim was to investigate whether repeated amphetamine injections have similar behavioral consequences to those induced by PTSD. Our results showed that massed amphetamine injections induced more anxiety than distributed injections, and led to avoidance of drug-associated cues avoidance, while distributed injections somewhat reduced the startle response, such as is seen in SPS. In addition, massed amphetamine injections induced a delayed behavioral sensitization clearly affected by the reactivity to novelty, reproducing results observed following exposure to traumatic events. Finally, all rats receiving repeated amphetamine injections exhibited a behavioral sensitization in response to exposure to drug-associated cues. Taken together, these data strengthen the position that drug addiction and PTSD share some common mechanisms that we tried to clarify in this paper.
authors.affiliation: Neuro-PSI UMR9197, Université Paris Sud, CNRS, Université Paris Saclay, Orsay F 91400, France. Electronic address: daniel.toledano@u-psud.fr.
authors.forename: Daniel
authors.initials: D
authors.lastname: Toledano
authors.affiliation: Neuro-PSI UMR9197, Université Paris Sud, CNRS, Université Paris Saclay, Orsay F 91400, France. Electronic address: pascale.gisquet@u-psud.fr.
authors.forename: Pascale
authors.initials: P
authors.lastname: Gisquet-Verrier
mesh_terms: D000221:Adaptation, Ocular / Q000187:drug effects; D000661:Amphetamine / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000503:physiopathology; D001362:Avoidance Learning / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003463:Cues; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000187:drug effects*; D008124:Locomotion / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D009812:Odorants; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects*; D012022:Reflex, Acoustic / Q000187:drug effects
chemical_list: D000697:Central Nervous System Stimulants; D000661:Amphetamine
keywords: Behavioral sensitization; Drug addiction; Posttraumatic stress disorder; Reactivity to novelty (HR–LR); Reminder cues