title: Novelty response and 50 kHz ultrasonic vocalizations: Differential prediction of locomotor and affective response to amphetamine in Sprague-Dawley rats.
abstract: BACKGROUND
  Novelty and sensation seeking (NSS) predisposes humans and rats to experiment with psychostimulants. In animal models, different tests of NSS predict different phases of drug dependence. Ultrasonic vocalizations (USVs) are evoked by psychomotor stimulants and measure the affective/motivation response to stimuli, yet the role NSS has on USVs in response to amphetamine is not determined.
  
  
  OBJECTIVE
  The aim of the present study was to determine if individual differences in NSS and USVs can predict locomotor and USV response to amphetamine (0.0, 0.3, and 1.0 mg/kg) after acute and chronic exposure.
  
  
  METHODS
  Thirty male rats were tested for their response to novelty (IEN), choice to engage in novelty (NPP), and heterospecific play (H-USV). Rats were administered non-contingent amphetamine or saline for seven exposures, and USVs and locomotor activity were measured. After a 14-day rest, rats were administered a challenge dose of amphetamine.
  
  
  RESULTS
  Regression analyses indicated that amphetamine dose-dependently increased locomotor activity and the NPP test negatively predicted treatment-induced locomotor activity. The H-USV test predicted treatment-induced frequency-modulated (FM) USVs, but the strength of prediction depended on IEN response.
  
  
  CONCLUSIONS
  Results provide evidence that locomotor activity and FM USVs induced by amphetamine represent different behavioral responses. The prediction of amphetamine-induced FM USVs by the H-USV screen was changed by the novelty response, indicating that the affective value of amphetamine-measured by FM USVs-depends on novelty response. This provides evidence that higher novelty responders may develop a tolerance faster and may escalate intake faster.
authors.affiliation: Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, Manhattan, KS, 66506-5302, USA. ejgarcia@k-state.edu.
authors.forename: Erik J
authors.identifier: http://orcid.org/0000-0003-4760-7048
authors.initials: EJ
authors.lastname: Garcia
authors.affiliation: Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, Manhattan, KS, 66506-5302, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Cain
mesh_terms: D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004361:Drug Tolerance; D005106:Exploratory Behavior / Q000187:drug effects* / Q000502:physiology; D005544:Forecasting; D008297:Male; D009042:Motivation / Q000187:drug effects / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014828:Vocalization, Animal / Q000187:drug effects* / Q000502:physiology
chemical_list: D000697:Central Nervous System Stimulants; D000661:Amphetamine
keywords: Amphetamine; Individual differences; Locomotor activity; Novelty/sensation seeking; Prediction; Sensitization; Ultrasonic vocalization