Abstract
After termination of a self-administered cocaine "binge," rats emit ultrasonic vocalizations (USVs) and these calls may represent affective distress. The present study investigated whether the rates of USVs as indices of withdrawal from a period of continuous access, depends on cocaine being self-administered versus given non-contingently. Five days after implantation of a jugular catheter, triads of rats that were matched for housing, food-training and surgery were placed into experimental chambers. The active rats were allowed to acquire self-administration of cocaine (0.5 mg) while the two yoked animals passively received either cocaine (0.5 mg) or saline according to the active animal's pattern of administration. Once the active animal responded at a stable rate over 3 days, with every third lever press being reinforced by cocaine (FR3), it was allowed free access to cocaine (0.5 mg) for 16 h. Subsequently, all animals were exposed to 18 air puffs (10 psi) at 0, or 1, 3, 5, 7 and 14 days after the "binge". Immediately following the binge, there was no significant difference in the rate of startle-induced USVs between the active cocaine group and the yoked saline group. However, the yoked or non-contingent cocaine rats emitted significantly higher rates of USVs immediately after the last cocaine infusion. At the time of the peak increase in USVs, the active and yoked cocaine groups were significantly different. For up to 5 days after unlimited cocaine access, the active and passive-cocaine groups showed an increase in USVs response when compared to the yoked saline group. The emerging increase in USVs and their gradual decline observed after termination of a cocaine "binge" can be interpreted as an abstinence phenomenon. The non-contingent cocaine appears to be highly aversive, as indicated by the immediate significant increase in the rate of USVs after termination of a cocaine "binge".
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
