title: Ultrasonic vocalization in rats self-administering heroin and cocaine in different settings: evidence of substance-specific interactions between drug and setting.
abstract: BACKGROUND
  Clinical and preclinical evidence indicates that the setting of drug use affects drug reward in a substance-specific manner. Heroin and cocaine co-abusers, for example, indicated distinct settings for the two drugs: heroin being used preferentially at home and cocaine preferentially outside the home. Similar results were obtained in rats that were given the opportunity to self-administer intravenously both heroin and cocaine.
  
  
  OBJECTIVE
  The goal of the present study was to investigate the possibility that the positive affective state induced by cocaine is enhanced when the drug is taken at home relative to a non-home environment, and vice versa for heroin.
  
  
  METHODS
  To test this hypothesis, we trained male rats to self-administer both heroin and cocaine on alternate days and simultaneously recorded the emission of ultrasonic vocalizations (USVs), as it has been reported that rats emit 50-kHz USVs when exposed to rewarding stimuli, suggesting that these USVs reflect positive affective states.
  
  
  RESULTS
  We found that Non-Resident rats emitted more 50-kHz USVs when they self-administered cocaine than when self-administered heroin whereas Resident rats emitted more 50-kHz USVs when self-administering heroin than when self-administering cocaine. Differences in USVs in Non-Resident rats were more pronounced during the first self-administration (SA) session, when the SA chambers were completely novel to them. In contrast, the differences in USVs in Resident rats were more pronounced during the last SA sessions.
  
  
  CONCLUSIONS
  These findings indicate that the setting of drug taking exerts a substance-specific influence on the ability of drugs to induce positive affective states.
authors.affiliation: Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Avvisati
authors.affiliation: Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Contu
authors.affiliation: Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy.
authors.forename: Emiliana
authors.initials: E
authors.lastname: Stendardo
authors.affiliation: Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Michetti
authors.affiliation: Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy.
authors.forename: Christian
authors.initials: C
authors.lastname: Montanari
authors.affiliation: Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Scattoni
authors.affiliation: Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy. aldo.badiani@uniroma1.it.|Sussex Addiction Research and Intervention Centre (SARIC), School of Psychology, University of Sussex, Brighton, UK. aldo.badiani@uniroma1.it.
authors.forename: Aldo
authors.initials: A
authors.lastname: Badiani
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage; D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage; D003932:Heroin / Q000008:administration & dosage*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D012646:Self Administration; D019966:Substance-Related Disorders / Q000523:psychology; D000069453:Ultrasonic Waves; D014828:Vocalization, Animal / Q000187:drug effects* / Q000502:physiology
chemical_list: D000701:Analgesics, Opioid; D018765:Dopamine Uptake Inhibitors; D003932:Heroin; D003042:Cocaine
keywords: Affect; Cocaine; Context; Drug abuse; Emotion; Environment; Heroin; Reward; Self-administration; Setting; USVs; Ultrasonic vocalizations