Mechanisms of Food-Seeking Relapse: Role of CRF, PYY3-36, and Hypocretin

1. Relapse to food seeking:Role of CRF, PYY3-36, and hypocretin Yavin Shaham Neurobiology of Relapse Section Behavioral Neuroscience Branch IRP/NIDA/NIH/DHHS, Baltimore Post-doctoral fellows: Sunila Nair, Udi Ghitza Students (NIH training program): Sarah Gray, Sam Golden, Tristan Adams-Deutsch CRF = Corticotropin-releasing factor PYY3-36 = Peptide YY3-36 Hypocretin = Orexin

2. Neurobiology of Relapse Section Shaham laboratory Staff scientist: Jennifer Bossert Post-doctoral fellows: Sunila Nair, Charles Pickens Post-baccalaureate students: Sam Golden, Kristina Wihbey, Tristan Adams-Deutsch Hope laboratory Staff scientist: Bruce Hope Post-doctoral fellow: Eisuke Koya Graduate student: Danielle Guez (Yale U) Post-baccalaureatestudent: Alex Berkow

3. Ongoing research projects 1. Relapse to food seeking 2. Context-induced reinstatement of heroin seeking 3. Incubation of cocaine craving (time-dependent increases in cue-induced cocaine seeking) 4. Incubation of conditioned fear (time-dependent increases in conditioned fear) 5. Neuronal mechanisms of context-dependent cocaine sensitization (Hope lab) Extramural collaborations: AD Le (Toronto U): Stress-induced relapse to alcohol (NIAAA) Geoff Schoenbaum (U of Maryland): Effect of cocaine self-administration on learning and memory (NIDA) Abraham Zangen (Weizmann Inst., Israel): Developing a novel conflict model of drug (NIDA) Marina Wolf and Micky Marinelli (Rosalind Franklin University): Accumbens synaptic plasticity and incubation of craving (NIDA)

4. Outline • A brief description of a reinstatement model—an animal model of relapse to drug-taking behavior • The adaptation of the reinstatement model to study: 1. Role of CRF in reinstatement of food seeking induced by: * A pharmacological stressor (yohimbine) * Acute re-exposure to food pellets (pellet priming) 2-3. Effect of PYY3-36 and hypocretin 1 receptor antagonist on reinstatement induced by: * Yohimbine * Pellet priming * Cue (a tone-light cue previously paired with pellet delivery)

5. The reinstatement model of drug relapse Self-administration training (Drug is available) Extinction (Drug is NOT available) TESTING (Drug is NOT available) Lever presses Drug priming Drug cues Stress Experimental day Reinstatement studies (1971-2007) X X 500 478 400 332 300 Cumulative # of publications 200 96 100 13 10 4 3 0 20 0 70 75 80 85 90 95 00 05 07 Year

6. Extra-hypothalamic CRF systems From Behan et al. 1996 Study 1 The role of CRF in reinstatement of food seeking induced by the pharmacological stressor yohimbine Hypothalamic-pituitary- adrenal (HPA) axis

7. Stress and relapse to maladaptive eating habits The clinical problem: Excessive eating of unhealthy food is a major health problem Stress can provoke relapse to unhealthy eating habits, and humans are particularly vulnerable to this effect when dieting The preclinical situation:This issue has not been explored in preclinical laboratory studies, which have primarily focused on the effect of stress on ongoing feeding behavior

8. Heroin Methamphetamine Alcohol Nicotine * 100 * * * 100 60 * * 120 80 75 45 * 60 80 Lever presses 50 30 40 40 25 15 20 0 0 0 0 0 1.25 2.5 0 0.625 1.25 0 2.5 0 1.25 2.5 Yohimbine dose (mg/kg, i.p.) Le et al. 2007 (Unpublished) Yap & Shaham. 2000 (unpublished) Shepard et al. 2004 Biol. Psychiatry Le et al. 2005 Psychopharmacology Why yohimbine? Yohimbine (an alpha-2 adrenoceptor antagonist) increases brain noradrenaline release and induces stress-like responses in humans and laboratory animals Yohimbine induces heroin craving in human addicts Yohimbine reinstates drug seeking in monkeys and rats

9. Heroin Cocaine Alcohol 60 No stress Intermittent footshock 45 * * Lever presses 30 * * * * 15 * 0 0 15 30 0 15 30 0 15 30 0 15 30 CP-154,526 dose (mg/kg) CP-154,526 dose (mg/kg) MTIP dose (mg/kg) Shaham et al. Psychopharmacology, 1998 Le et al. Psychopharmacology, 1998 Gehlert et al. J Neurosci, 2007 Why CRF? CRF injections into the ventricles and several extrahypothalamic sites (BNST, VTA, median raphe) reinstate drug seeking Non-selective and selective CRF1 receptor antagonists attenuate stress-induced reinstatement of drug seeking

10. Experimental procedure 45 mg pellets: 25% fat 48% carbohydrate Pellet self-administration Three 3-h sessions/d every other day (FR-1; 20 sec timeout) Extinction pellets NOT available Tests for reinstatement pellets NOT available Limited access to regular food: ~75% of daily intake Limited access to regular food: ~75% of daily intake (diet condition) Exposure to: Yohimbine Non-contingent pellet (priming)

11. Changes in body weight during training, extinction, and reinstatement (n=35) Daily weight fluctuations Training 20 10 Weight change (g) 0 Extinction & Reinstatement -10 Pellets available No pellets -20 10 20 30 40 Day Pellet self-administration Three 3-h sessions/d every other day (FR-1; 20 sec timeout) Extinction (pellets NOT available) Tests for reinstatement (pellets NOT available) Limited access to regular food: ~75% of daily intake Limited access to regular food: ~75% of daily intake (diet condition) Ghitza et al. Neuropsychopharmacology, 2006

12. Development of “compulsive” food-taking behavior during training Timeout responses 1200 Pellets 900 Responses or pellets (9 h) 600 300 0 2 4 6 8 10 12 Training day Tests for reinstatement Pellet self-administration Three 3-h sessions/d every other day (FR-1; 20 sec timeout) Extinction Limited access to regular food: ~75% of daily intake Limited access to regular food: ~75% % of daily intake (diet condition)

13. Antalarmin dose 9 h/day Vehicle 600 100 20 mg/kg 40 mg/kg 450 75 Lever presses (3 h) Lever presses 300 50 * * 150 25 3 h/day 0 0 0 2.0 Pellet priming 1 2 3 4 5 6 7 8 9 10 Yohimbine dose (mg/kg, i.p.) Extinction day The CRF1 receptor antagonist antalarmindecreases yohimbine-induced reinstatement of food seeking Tests for reinstatement (pellets NOT available) Pellet self-administration Extinction (pellets NOT available) Limited access to regular food: ~75% of daily intake Limited access to regular food: ~75% of daily intake (diet condition) Reinstatement Extinction Antalarmin was synthesized by Dr. Kenner Rice

14. Yohimbine-induced plasma corticosterone release Yohimbine-induced reinstatement 750 80 Vehicle Vehicle Yohimbine (1.25 mg/kg) Yohimbine (1.25 mg/kg) 60 500 Lever presses (1 h) Corticosterone (ng/ml) 40 * 250 * 20 0 0 0 10 20 0 20 Antalarmin dose (mg/kg, i.p.) Antalarmin dose (mg/kg, i.p.) Antalarmindecreases yohimbine-induced reinstatement of alcohol seeking Marinelli et al. Psychopharmacology, 2007

15. 100 40 Antalarmin dose * 30 75 Vehicle * 20 mg/kg 20 50 Social bouts (10 min) Antisocial bouts (10 min) 10 25 0 0 0 2.0 0 2.0 Yohimbine dose (mg/kg, i.p.) Yohimbine dose (mg/kg, i.p.) The CRF1 antagonist antalarmin reverses yohimbine’s effects on social and “antisocial” behaviors Social behavior “Antisocial” behavior Social and “antisocial” behaviors were evaluated using a social interaction test: Social behavior: crawling together, grooming, sniffing, licking “Antisocial” behavior: wrestling, distress vocalization, confrontation

16. Conclusions: Study 1 As in the case of drug relapse, the reinstatement model can be used to study mechanisms underlying relapse to maladaptive eating habits The effect of antalarmin on yohimbine-induced reinstatement of food and alcohol seeking is likely mediated by extrahypothalamic CRF1 receptors

17. Project 2 Effect of PYY3-36 on yohimbine-, pellet-priming- and cue-induced reinstatement of high-fat food seeking Background The gut peptide PYY3-36 is an endogenous Y2 NPY receptor agonist that decreases home-cage feeding after systemic or arcuate nucleus injections PYY3-36 systemic effects are reversed by systemic or arcuate injections of the Y2 receptor antagonist BIIE0246.

18. Batterham + 9 authors (2002) Gut hormone PYY(3-36) physiologically inhibits food intake.Nature 418:650-654. Batterham + 7 authors (2003) Inhibition of food intake in obese subjects by peptide YY3-36. N Engl J Med 349:941-948. Pittner + 9 authors(2004) Effects of PYY(3-36) in rodent models of diabetes and obesity. Int J Obes Relat Metab Disord 28, 963-971 But…. Tschop + 42 authors (2004) Does gut hormone PYY3-36 decrease food intake in rodents?Nature 430:1 p following 165; discussion 162 p following 165. Boggiano + 36 authors (2005) PYY3-36 as an anti-obesity drug target. Obesity Reviews 6:307-322 * The effect of PYY(3-36) on operant food self-administration and reinstatement has not been assessed

19. Experimental procedure (Tone-light cue NOT available) (Tone-light cue available) X X Pellet self-administration Two 3-h sessions/d every other day (FR-1; 20 sec timeout) Extinction pellets NOT available Tests for reinstatement pellets NOT available Limited access to regular food: ~65% of daily intake Limited access to regular food: ~65% of daily intake (diet condition) Exposure to: Yohimbine Non-contingent pellet Cue 45 mg pellets: 35% fat 45% carbohydrate

20. 225 150 Food pellets (3 h) 75 0 0 100 200 0 100 200 PYY3-36 dose (µg/kg, i.p.) PYY3-36 has a minimal effect on high-fat pellet self-administration Pellet self-administration two 3-h sessions/d every other day (FR-1; 20 sec timeout) Session 1: Total intake Session 2: Total intake Limited access to regular food: ~65% of daily intake Ghitza, Nair et al. The Journal of Neuroscience, 2007

21. Pellet priming Cue 100 100 No cue No pellet Cue 75 75 Pellet Lever presses (3 h) Lever presses (3 h) 50 * 50 * * * 25 25 0 0 0 100 200 0 100 200 PYY3-36 dose (µg/kg, i.p.) PYY3-36 dose (µg/kg, i.p.) Yohimbine 250 Vehicle 200 Yohimbine (2.0 mg/kg) 150 Lever presses (3 h) 100 50 0 0 100 200 PYY3-36 dose (µg/kg, i.p.) PYY3-36 inhibits pellet-priming- and cue-induced reinstatement, but not yohimbine-induced reinstatement

22. Conclusions: PYY3-36 Systemic PYY3-36 decreased pellet-priming-induced reinstatement at doses that had minimal effect on ongoing high-fat food self-administration The systemic effect of PYY3-36 on reinstatement generalizes to cues- but not to yohimbine-induced reinstatement of food seeking The systemic effect of PYY3-36 is dependent on Y2 receptors Systemic PYY3-36 had no effect on reinstatement of heroin seeking, suggesting that its effects are specific to food relapse

23. Prepro-hypocretin Hypocretin 1 Hypocretin 2 Hypocretin 1 receptor Hypocretin 2 receptor Project 3 Effect of the hypocretin 1 receptor antagonist SB 334867 on high-fat food self-administration and relapse to food-seeking in rats The hypocretins (orexins) From Sakurai, 2006 and 2007

24. Why hypocretin 1 receptors? Systemic injections of SB 334,867 decrease home-cage food intake and reverse hypocretin 1-induced increases in food intake (Rodgers et al. 2002) Systemic injections of SB 334,867 decrease: Reinstatement of morphine conditioned place preference induced stimulation of lateral hypothalamus hypocretin neurons (Harris et al. 2005) Footshock stress-induced reinstatement of cocaine seeking (Boutrel et al. 2005) Cue-induced reinstatement of alcohol seeking (Lawrence et al. 2006)

25. Time course Pellet intake 400 Vehicle 10 mg/kg 300 * 20 mg/kg Pellets * Pellets (3 h) 200 100 0 0 10 20 SB 334867 dose (mg/kg, i.p.) Timeout lever presses per pellet Training 6 50 1500 Timeout responses Pellets 40 4 1000 Timeout responses/pellet 30 Pellets or lever presses 2 500 20 10 0 0 0 10 20 1 2 3 4 5 6 7 8 9 SB 334867 dose (mg/kg i.p.) 0 Training session 30 60 90 120 150 180 Session minutes SB 334,867 decreases high-fat pellet self-administration Nair et al. British Journal of Pharmacology, 2008

26. Hypocretin 1-induced reinstatement Effect of SB 334,867 100 100 Vehicle * 10 mg/kg 75 75 20 mg/kg Lever presses (3 h) 50 50 Lever presses (3 h) 25 25 0 0 0 3.0 6.0 0 6.0 Hypocretin 1 dose (µg, icv) Hypocretin 1 dose (µg, icv) SB 334,867 has no effect on hypocretin 1-induced reinstatement of food seeking

27. Yohimbine Pellet priming Cue 100 Vehicle Vehicle Vehicle 75 20 mg/kg 20 mg/kg 20 mg/kg Lever presses (3 h) 50 25 0 0 2.0 No pellet Pellet No cue Cue Yohimbine (mg/kg, i.p.) SB 334,867 has no effect on pellet-priming-, pellet-cue- or yohimbine-induced reinstatement of food seeking

28. Conclusions: hypocretin 1 receptor The hypocretin 1 receptor plays a role in the self-administration of high-fat pellets The hypocretin 1 receptor likely plays a minimal role in reinstatement induced acute re-exposure to hypocretin 1, food priming, cues and stress

29. Implications of the findings Our data suggest: 1. A dissociation between the neuronal mechanisms mediating stress-induced relapse to food seeking versus food priming- or cue-induced relapse 2. A potential dissociation between the neuronal mechanisms mediating food self-administration versus food priming- or cue-induced relapse From Shalev et al. Neurobiology of relapse to heroin and cocaine seeking: a review. Pharmacol Rev, 2002 “Taken together, it appears that multiple and dissociable brain systems are involved in relapse to heroin and cocaine seeking induced by drug priming, conditioned cues and stress. Somewhat surprisingly, it also appears that the neuronal events that mediate heroin- or cocaine-induced reinstatement are to some degree different from those involved in their reinforcing effects.”

30. Clinical implications CRF1 receptor antagonists (currently in clinical development for the treatment of anxiety, depression and drug abuse) should be considered as pharmacological adjuncts in dietary treatments of maladaptive or excessive eating habits PYY3-36 (currently in clinical development for the treatment of obesity)may be a more effective treatment for relapse prevention than for decreasing ongoing high-fat food intake Hypocretin 1 receptor antagonists may be a more effective treatment for decreasing ongoing high-fat food intake than for relapse prevention Acknowledgments Dr. Jennifer Bossert Jamie Uejima Kristina Wihbey Dr. Kenner Rice “The best material model for a cat is another, or preferably the same cat”Norbert Wiener, 1945