1. CP-154,526, a CRF type-1 receptor antagonist, attenuates the cue-and methamphetamine-induced reinstatement of extinguished methamphetamine- seeking behavior in rats Moffett and Goeders (2007) Presented by Amanda Jonas

2. Acquisition of psychostimulant self-administration Repeated tail pinch Social Stress Social Isolation Electric Footshock

3. Ketoconazole Corticosterone synthesis inhibitor Inhibits 11β-hydroxylase Decrease low-dose cocaine self-administration Also used to treat fungal infections Shown to partially attenuate increases in plasma corticosterone Reinstatement of cocaine-seeking behavior Exposure to electric footshock Cocaine pretreatment

4. CP-154,526 Corticotropin-releasing hormone (CRF) type 1 receptor antagonist Decreases cocaine intake across several doses of cocaine Centrally acting antagonist at CRF1 receptors Has been shown to attenuate the airpuff startle- induced rise in plasma corticosterone and adrenocorticotropic hormone (ACTH)

5. Extinction/Reinstatement Model Often used as an animal model of relapse Rats trained to self-administer a drug until stable behavior maintained Rats exposed to extinction Drug-seeking behavior reinstated by presentation of specific stimuli

6. Specific Stimuli Acute exposure to a stressor Stimuli previously paired with the drug Acute exposure to the self-administered drug

7. Hypothalamo-pituitary-adrenal (HPA) axis Role in acquisition and maintenance of psychostimulant self-administration Potential role in relapse

8. Purpose Investigate the potential role for the HPA axis in the ability of environmental stimuli and priming infusions of methamphetamine to stimulate extinguished methamphetamine seeking by using two drugs that act on different levels of the HPA axis

9. Hypothesis CP-154,526 and Ketoconazole will attenuate the cue- and methamphetamine- induced reinstatement of methamphetamine-seeking behavior in a manner similar to cocaine-trained rats

10. Subjects 85 male Wistar rats 80-100 days old Housed individually Reversed 12-h ligh-dark cycle Maintained at 85 to 90% of free-feeding body weights by presentation of food pellets during behavioral sessions Water access was ad libitum

11. Venous Catheterization and Drug Delivery Implanted with chronic indwelling jugular catheters 22-gauge cannula guide

12. i.c.v CP-154,526 infusions Implanted with a 22-gauge guide cannula Into the right or left lateral cerebral ventricle

13. Apparatus Sound-attenuating chambers Equipped with two retractable response levers on either side Stimulus light about each lever House light mounted on wall opposite levers with tone source wired directly to the light

14. Self-Administration Training Trained to self-administer methamphetamine by pressing a lever under a continuous schedule of reinforcement 2-h daily sessions 5 days a week Two levers Methamphetamine (Active) Stimulus light illuminated when methamphetamine available Inactive

15. Extinction Daily 2-h sessions The stimulus light was on for the active lever Brief (0.6 s) darkening of the lever light when pressed No methamphetamine was delivered

16. Extinction continued Session continued until the total number of responses were equal to or lower than 20% of the mean number of responses to the active lever during self-administration After extinction, tested for reinstatement of methamphetamine seeking using the cues

17. Cue-induced reinstatement Conditions were similar to self-administration except for methamphetamine was not delivered Ketoconazole or vehicle was injected 30 min before the start of the test session in the home cage After a single response to the active lever, the house light was illuminated and tone sounded for 5.6 s After reinstatement training, rats returned to self- administration training

18. Cue-induced for i.c.v CP-154,526 Rats implanted with i.c.v. underwent cue-induced reinstatement testing the same as ketoconazole CP-154,526 or vehicle was injected 30 min before the session After testing, returned to self-administration training and eventually retested Each rat received vehicle and CP-154,526 on separated occasions using a counter-balanced design

19. Figure 1a

20. Figure 1b

21. Table 2

22. Figure 2

23. Methamphetamine-induced reinstatement Conditions identical to extinction Ketoconazole, CP-154,526, or vehicle was injected 30 min before the start of the test session in the home cage Before the start of the session, rats received a single methamphetamine priming infusion After reinstatement training, rats returned to self- administration training

24. Comparisons Effects of ketoconazole 50 mg/kg vs. vehicle on responding after a 0.12 mg/kg priming infusion Ability of CP-154,526 20 mg/kg dose vs. vehicle to attenuate methamphetamine-primed reinstatement at the 0.12 mg/kg dose Effects of two doses of CP-154,526 (20 mg/kg and 40 mg/kg) vs. vehicle on 0.24 mg/kg methamphetamine-induced reinstatement

25. Retesting Received a minimum of 5 self- administration retraining sessions before being placed back into extinction Tested for reinstatement a maximum of 3 times using only one stimulus Once after receiving vehicle Twice after receiving different doses of the test drugs

26. Figure 3a

27. Figure 3b

28. Figure 4

29. Table 1

30. Food Training Trained to respond under a fixed-interval (F1) schedule of food reinforcement during daily 1-h sessions Initially trained on a FI25 schedule Stimulus light about food lever illuminated every 25 s Food pellet presented when lever was pressed when it was illuminated Houselight illuminated and a tone (66 dB) presented for 5.6 d

31. Food Training continued Fixed interval was gradually raised to F150 schedule Used to produce rates of responding that were similar to methamphetamine self-administration Training continued until 3 consecutive sessions with less than a 10% variation in active lever responding occurred Tested on the following day (identical to training sessions)

32. Food Training continued Pretreated with either CP-154,526 or vehicle 30 min before the start of the test session in the home cage Number of active lever responses during the test session were compared to those on the last day of training Returned to food training for a minimum of 5 sessions before being tested with a different drug or dose

33. Food Training continued Tested a maximum of 3 times Once after receiving vehicle Twice after receiving different doses of CP-154,526 Six of the rats used in this experiment, implanted with catheters and used in addition to naïve rats for ketoconaxole 3 months elapsed before the reinstatment test session

34. Table 3

35. Discussion Ketoconazole and Cp-154,526 reversed the cue-induced reinstatement of methamphetamine seeking CP-154,526 attenuated the cue-induced reinstatement of methamphetamine seeking and methamphetamine-induced reinstatement

36. Discussion continued Results indicate that CRF, but not corticosterone, plays a crucial role in the ability of environmental cues and priming injections to stimulate methamohetamine seeking The cues paired with self-administration methamphetamine as well as priming infusions of methamphetamine may have acted as stressors during the reinstatement test session lead to stimulating the release of CRF to increase plasma corticosterone

37. Discussion continued Potential value of the development of CRH receptor antagonists as aids in preventing relapse in drug-dependent individuals

38. Thank you!