Neurobiology of Addiction: Shedding Light from the Dark Side
George F. Koob, Ph.D. Professor and Chair Committee on the Neurobiology of Addictive Disorders The Scripps Research Institute La Jolla, California Koob GF. The neurobiology of addiction: a neuroadaptational view relevant for diagnosis. Addiction, 2006, 101(suppl 1):23-30. Koob GF, Le Moal M. Addiction and the anti-reward system. Annual Review of Psychology, 2008, 59:29-53. Koob GF. A role for brain stress systems in addiction. Neuron, 2008, 59:11-34. When people talk about drugs, they assume people take drugs because they enjoy it, Williams told the Toronto Star. But really, it's no different from overeating or watching too much television or drinking too much. You take drugs to make yourself feel better, to fill a hole. -Ricky Williams -Byline Damien Cox, Toronto Star, May 29, 2006 Key Findings and Conclusions
Addiction loss of control over drug intake and compulsive drug taking driven by elements of impulsivity and compulsivity that are mediated by separate but overlapping neurocircuitry Acute rewarding effects of drugs of abuse are mediated by neurochemical elements such as dopamine and opioid peptides in the nucleus accumbens and amygdala Acute withdrawal from all major drugs of abuse produces increases in reward thresholds, increases in anxiety-like responses and increases in CRF in the amygdala that are of motivational significance Compulsive drug use associated with dependence is mediated by not only loss of function of reward systems but recruitment of brain stress systems such as corticotropin releasing factor, norepinephrine and dynorphin in the extended amygdala Brain-arousal stress systems in the extended amygdala--- may be key components of not only for the negative emotional states that drive dependence on drugs of abuse but also may overlap with the negative emotional components of other psychopathologies Neurocircuitry of Addiction
KoobG/CNAD/dia1/090808jh Derived from:Koob G, Everitt, Band Robbins T,Reward, motivation, and addiction. In: Squire LR, Berg D, Bloom FE, du Lac S, Ghosh A, Spitzer NC (Eds.), Fundamental Neuroscience, 3rd edition, Academic Press, Amsterdam, 2008, pp Key Common Neuroanatomical Structures in Addiction
Nucleus Accumbens and Central Nucleus of theAmygdala Forebrain structures involved in the rewarding effects of drugs of abuse and drives the binge intoxication stage of addiction.Contains key reward neurotransmitters: dopamine and opioid peptides Extended Amygdala Composed of central nucleus of the amygdala, bed nucleus of the stria terminalis, and a transition zone in the medial part of the nucleus accumbens. Contains brain stress neurotransmitter, corticotropin releasing factor that controls hormonal, sympathetic, and behavioral responses to stressors, and is involved in the anti-reward effects of drug dependence Medial Prefrontal Cortex neurobiological substrate for executive function that is compromised in drug dependence and plays a key role in facilitating relapse. Contains major glutamatergic projection to nucleus accumbens and amygdala Neurocircuitry of Addiction
KoobG/CNAD/dia1/090808jh Derived from:Koob G, Everitt, Band Robbins T,Reward, motivation, and addiction. In: Squire LR, Berg D, Bloom FE, du Lac S, Ghosh A, Spitzer NC (Eds.), Fundamental Neuroscience, 3rd edition, Academic Press, Amsterdam, 2008, pp KoobG/NP/dia3/031902jh From: Koob GF, Alcohol Clin Exp Res, 2003, 27: Positive and Negative Reinforcement- Definitions
Positive Reinforcement defined as the process by which presentation of a stimulus (drug)increases the probability of a response (non dependent drug taking paradigms). Negative Reinforcement defined as a process by which removal of an aversive stimulus (negative emotional state of drug withdrawal) increases the probability of a response (dependence-induced drug taking) Stages of the Addiction Cycle
KoobG/NP/dia2/051605jh Animal Models for the Different Stages of the Addiction Cycle
Animal Models for the Binge/Intoxication Stage 1. Oral or intravenous drug self-administration 2. Brain stimulation reward 3. Place preference Animal models for the Withdrawal/Negative Affect Stage 1. Brain stimulation reward 2. Place aversion Animal Models for the Transition to Addiction 1. Dependence-induced drug taking 2. Escalation in drug self-administration with prolonged access 3. Drug taking despite aversive consequences Animal Models for the Preoccupation/Anticipation (Craving) Stage 1. Drug- induced reinstatement 2. Cue- induced reinstatement 3. Alcohol Deprivation Effect 4.Stress- induced reinstatement 008KoobG/NP/sca3c/011000jh.psd Cocaine Self-Administration
Was: KoobG/NP/dia1/060899jh Became: KoobG/NP/dia2/092502jh From:Caine SB, Lintz R and Koob GF. in Sahgal A (ed) Behavioural Neuroscience: A Practical Approach, vol. 2, IRL Press, Oxford, 1993, pp Neurochemical Circuitry in Drug Reward
KoobG/NP/dia6/041204jh From:Koob GF, Clin Neurosci Res, 2005, 5: KoobG/NP/sca1/030104jh Pieter Bruegel Protocol for Initiation of Lever Pressing for Oral Ethanol Self-Administration in the Rat
Rats trained to lever press on a FR-1 schedule % saccharin Ethanol added to the saccharin solution Access to ethanol and water or ethanol or saccharin and water KoobG/NP/gra1/050202jh Initiation of the free-choice operant task: ethanol (10%) and water From: Rassnick S, Pulvirenti L and Koob GF, Alcohol, 1993, 10: Effects of Methylnaloxonium on Ethanol Self-Administration in Non-Dependent Rats
KoobG/NP/gra3/110304jh From: Heyser CJ, Roberts AJ, Schulteis G and Koob GF, Alcohol Clin Exp Res, 1999, 23: Converging Acute Actions of Drugs of Abuse on the Ventral Tegmental Area and Nucleus Accumbens
KoobG/MIND/dia1/053006jh From: Nestler EJ, Nat Neurosci, 2005, 8: no# ppt: Svayasamin Standard Pattern of Affective Dynamics Produced by Novel and Repeated Unconditioned Stimulus
KoobG/MIND/gra9/013106jh From: Solomon RL, American Psychologist, 1980, 35: Mood Changes Associated with Plasma Levels of Cocaine During Coca Paste Smoking
KoobG/MIND/gra4/020706jh From: Van Dyke C and Byck R, Cocaine, Scientific American, 1982, 246: Protocol for Drug Escalation
1) Initial Training Phase 2) Escalation Phase 3) Testing Phase Short Access22 x 1-hr SA session All Rats1-hr SA session Fixed Ratio mg cocaine/injection Neuropharmacological probes Long Access22 x 6-hr SA session KoobG/NP/wor1/030104jh Protocol from: Ahmed SH and Koob, Science, 1998, 282: Change in Brain Stimulation Reward Thresholds in Long-Access (Escalation) vs. Short-Access (Non-Escalation) Rats KoobG/MIND/gra13/013106jh From: Ahmed SH, Kenny PJ, Koob GF and Markou A, Nature Neurosci, 2002, 5: Progressive-ratio Responding for Cocaine in Long- and Short-access Rats
KoobG/CNAD/gra5/041108jh From:Wee S, Mandyam CD, Lekic DM and Koob GF, Eur Neuropsychopharmacol, 2008, 18: Effect of a-flupenthixol on Cocaine Self-Administration in Escalated and Non-Escalated Animals
KoobG/NP/gra1/061103jh From: Ahmed SH and Koob GF, Psychopharmacology, 2004, 172: Escalation of Methamphetamine Self-administration in Rats
KoobG/CNAD/gra1/052907jh Adapted from: Wee S, Wang Z, Woolverton WL, Pulvirenti L and Koob GF, Neuropsychopharmacology, 2007, 32: Effects of Aripiprazole on Methamphetamine Self-administration (0
Effects of Aripiprazole on Methamphetamine Self-administration (0.05 mg/kg/inf progressive-ratio) KoobG/CNAD/gra10/100407jh Adapted from:Wee S, Wang Z, Woolverton WL, Pulvirenti L and Koob GF, Neuropsychopharmacology, 2007, 32: Sampling of Interstitial Neurochemicals by in vivo Microdialysis
Allows sampling of neurochemicals inconscious animals (correlate brainchemistry with behavior). Implanted so that semi-permeableprobe tip is in specific brain region ofinterest. Substances below the membrane MWcutoff diffuse across membrane basedon concentration gradient. Both neurochemical sampling andlocalized drug delivery are possible. Collaborators: Dr. Friedbert Weiss, Dr. Larry Parsons, Dr. Emilio Merlo-Pich, Dr. Regina Richter Extracellular DA and 5-HT in the Nucleus Accumbens During Cocaine Self-Administration and Withdrawal
KoobG/NP/gra1/010302jh From: Parsons LH, Koob GF and Weiss F, J Pharmacol Exp Ther, 1995, 274: Decreased Dopamine D2 Receptor Activity in a Cocaine Abuser
no# ppt: volkow d2 activity From:Volkow ND, Fowler JS, Wang GJ, Hitzemann R, Logan J, Schlyer DJ, Dewey S and Wolf AP, Synapse, 1993, 14: Negative Hedonic Effects
Reward Transmitters Implicated in the Motivational Effects of Drugs of Abuse Positive Hedonic Effects Negative Hedonic Effects of Withdrawal Dopamine Opioid peptides Serotonin GABA Dopamine dysphoria Opioid peptides ... pain Serotonin dysphoria GABA anxiety, panic attacks KoobG/NP/wor2/030104jh Standard Pattern of Affective Dynamics Produced by Novel and Repeated Unconditioned Stimulus
KoobG/MIND/gra9/013106jh From: Solomon RL, American Psychologist, 1980, 35: Anti-Reward Transmitters Implicated in the Motivational Effects of Drugs of Abuse
Dynorphin dysphoria CRF stress Norepinephrine stress NPY anti-stress KoobG/NP/wor2/030104jh CNS Actions of Corticotropin-Releasing Factor (CRF)
KoobG/NP/dia2/011000jh Major CRF-Immunoreactive Cell Groups and Fiber Systems in the Rat Brain
KoobG/NP/dia1/061499jh From: Swanson LW, Sawchenko PE, Rivier J and Vale W, Neuroendocrinology, 1983, 36: CRF Produces Arousal, Stress-like Responses, and a Dysphoric, Aversive State
Paradigm CRF Agonist CRF Antagonist Acoustic startle Facilitates startle Blocks fear-potentiated startle Elevated plus maze Suppresses exploration Reverses suppression of exploration Defensive burying Enhances burying Reduces burying Fear conditioning Induces conditioned fear Blocks acquisition of conditioned fear Cued electric shock Enhances freezing Attenuates freezing Taste / Place Conditioning Produces place aversion Weakens drug-induced place aversion no# ppt: crfagon/antagon text Sampling of Interstitial Neurochemicals by in vivo Microdialysis
Allows sampling of neurochemicals inconscious animals (correlate brainchemistry with behavior). Implanted so that semi-permeableprobe tip is in specific brain region ofinterest. Substances below the membrane MWcutoff diffuse across membrane basedon concentration gradient. Both neurochemical sampling andlocalized drug delivery are possible. Collaborators: Dr. Friedbert Weiss, Dr. Larry Parsons, Dr. Emilio Merlo-Pich, Dr. Regina Richter Withdrawal-induced Increases in Extracellular Levels of CRF
KoobG/CNAD/gra1c/020608jh Rodent model of excessive drinking during withdrawal(Roberts et al 1996, 2000; ODell et al 2004)
Self-administration training Sweetened solution fading used to train animals to lever press for: 10%w/v EtOHvsWater Chronic intermittent alcohol vapors (4+ wks) Target blood alcohol levels (BALs): g% Dependence induction Withdrawal from alcohol vapors Negative emotional state: Anxiety-like behavior Reward threshold deficits Increased CRF release in the extended amygdala Excessive drinking: 2-3 fold higher alcohol intake Increased progressive ratio breakpoints Relapse following prolonged abstinence Enhanced Ethanol Self-Administration During Withdrawal in Dependent Animals
*** *** KoobG/NP/gra1/121305jh n = 6/group *p < vs. Nondependent-EtOH From: Funk C and Koob GF, unpublished results. 40 CRF1 Specific Antagonists MPZP
KoobG/CNAD/gra1/100807jh From:Richardson HN, Zhao Y, Fekete EM, Funk CK, Wirsching P, Janda KD, Zorrilla EP and Koob GF, Pharmacol Biochem Behav, 2008, 88: Effect of CRF Antagonist D-Phe-CRF12-41 Central Nucleus of the Amygdala
KoobG/MIND/gra1/013106jh From: Funk C, ODell LE and Koob GF, J Neurosci, 2006, 26: 1941 Good Housekeeping Total 23 h Active and Inactive Responding after Repeated 72 h Nicotine Deprivation Cycles Followed by 4 Days of Self-administration KoobG/CNAD/gra5/100407jh From:George O, Ghozland S, Azar MR, Cottone P, Zorrilla EP, Parsons LH, ODell LE, Richardson HN and Koob GF, Proc Natl Acad Sci USA, 2007, 104: Effect of CRF1 Antagonism on Nicotine Self-administration in Rats with Extended Access
KoobG/CNAD/gra3/100407jh From:George O, Ghozland S, Azar MR, Cottone P, Zorrilla EP, Parsons LH, ODell LE, Richardson HN and Koob GF, Proc Natl Acad Sci USA, 2007, 104: CRF1 Antagonist has No Effect on Baseline Responding for Nicotine in Rats with Unlimited Access
KoobG/CNAD/gra1/100407jh From:George O, Ghozland S, Azar MR, Cottone P, Zorrilla EP, Parsons LH, ODell LE, Richardson HN and Koob GF, Proc Natl Acad Sci USA, 2007, 104: Role of Corticotropin-releasing Factor in Dependence
Drug CRF antagonist effects on withdrawal-induced anxiety-like responses Withdrawal-induced changes in extracellular CRF in CeA CRF antagonist effects on dependence-induced increases in self-administration CRF antagonist reversal of stress-induced reinstatement Cocaine Opioids Ethanol Nicotine 9-tetrahydrocannabinol * nt nt KoobG/CNAD/wor2/021908jh.ppt retyped = aversive effects with place conditioning. nt = not tested. CeA = central nucleus of the amygdala. * Non-dependent Dependent
Positive Reinforcement Negative Non-dependent Dependent Negative Reinforcement Positive KoobG/CNAD/dia3/030607jh animated Stress and Anti-stress Neurotransmitters Implicated in the Motivational Effects of Drugs of Abuse
Corticotropin-releasing factor Neuropeptide Y Norepinephrine Nociceptin (orphanin FQ) Vasopressin KoobG/NP/wor2/030104jh Orexin (hypocretin) Dynoprhin Brain Arousal-Stress System Modulation in the Extended Amygdala
KoobG/CNAD/dia9b/012508jh Pain, Emotions, and the Amygdala
KoobG/CNAD/dia3/021408jh From: Neugebauer V, Li W, Gird GC and Han JS, The Neuroscientist, 2004, 10: Allostatic Change in Mood State associated with Transition to Drug Addiction
KoobG/NP/dia4/053102jh Adapted from: Koob GF and Le Moal M, Neuropsychopharmacology, 2001, 24: Key Findings and Conclusions
Addiction loss of control over drug intake and compulsive drug taking driven by elements of impulsivity and compulsivity that are mediated by separate but overlapping neurocircuitry Acute rewarding effects of drugs of abuse are mediated by neurochemical elements such as dopamine and opioid peptides in the nucleus accumbens and amygdala Acute withdrawal from all major drugs of abuse produces increases in reward thresholds, increases in anxiety-like responses and increases in CRF in the amygdala that are of motivational significance Compulsive drug use associated with dependence is mediated by not only loss of function of reward systems but recruitment of brain stress systems such as corticotropin releasing factor, norepinephrine and dynorphin in the extended amygdala Brain-arousal stress systems in the extended amygdala--- may be key components of not only for the negative emotional states that drive dependence on drugs of abuse but also may overlap with the negative emotional components of other psychopathologies Neurobiology of Drug Addiction Koob Laboratory
Postdoctoral Fellows Nick Gilpin Sunmee Wee Laura Orio Kaushik Misra Scott Edwards Candice Contet Cindy Funk Brendan Walker Tom Greenwell Sandy Ghozland Chitra Mandyam Dong Ji Research Assistants Bob Lintz Richard Schroeder Elena Crawford Molly Brennan Maury Cole Tess Kimber Yanabel Grant Administrative Assistants Lisa Maturin Mellany Santos Marisa Gallego Staff Scientists Olivier George Bob Purdy Heather Richardson Special thanks: Mike Arends (Senior Research Assistant) Janet Hightower (TSRI Biomedical Graphics) TSRI Chemists Kim Janda Tobin Dickerson Ed Roberts KoobG/NP/wor1/070902jh Support from: Pearson Center for Alcoholism and Addiction Research National Institute on Alcohol Abuse and Alcoholism National Institute on Drug Abuse National Institute of Diabetes and Digestive and Kidney Diseases