# Presentation: 767497

## Opioid Receptors –The Basis of Pain Relief and Addiction:Bidirectional Translational Research

**Mary Jeanne Kreek, M.D.**
***Patrick E. and Beatrice M. Haggerty Professor***
**Head of Laboratory**
**The Laboratory of the Biology of Addictive Diseases**
**The Rockefeller University**
**March 5, 2007**
**Pain, Opioids, and Addiction:**
**An Urgent Problem for Doctors and Patients**
**National Institutes of Health**
**Bethesda, MD**

**funded primarily by NIH-NIDA, NIH-NIMH, NIHCRR and NYS OASAS**

## Pain, Addictions, and theEndogenous Opioid System

**  ****Heroin Addiction**
**  ****Cocaine Dependency**
**  ****Alcoholism                        ****	**

**Pain, Addictions, and the****Endogenous Opioid System**

**Pain is modulated by endogenous opioid peptides**

***Kreek, 2007***

**Role of endogenous opioid system in each:**
**  ****Extent of Role?**
**  ****Precise Mechanism of Role?                        ****	**

**Exogenous opioids are effective analgesic agents**

**Many drugs of abuse act at or impact upon the endogenous opioid system**

## Endogenous Opioidsand their Receptors

***LaForge, Yuferov and Kreek, 2000***

## Role of Mu Opioid Receptor and Related EndorphinSystems in Normal Physiological Functions*

**Role of Mu Opioid Receptor and Related Endorphin****Systems in Normal Physiological Functions***

**Endogenous Response to Pain**
**Neuroendocrine Functions**
**Stress responsive systems including****hypothalamic-pituitary-adrenal axis**
**Reproductive function including****hypothalamic-pituitary-gonadal axis**
**  ****Immunological Function**
**  ****Gastrointestinal Function**
**  ****Cardiovascular Function**
**  ****Pulmonary Function**
**  ****? Mood, Affect; Cognition**

***Kreek, 2007***

## Prevalence of Specific Drug Abuse and Vulnerability to Develop Addictions

**	****Alcohol Use – ever****	****~****	****177 million****Alcoholism****	****~****	****15 million**
**	****Cocaine Use – ever****	****~****	****26 million****Cocaine Addiction****	****~****	****2 to 3 million**
**	****Heroin Use – ever****	****~****	****2.5 to 3 million****Heroin Addiction****	****~****	****0.5 to 1 million**
**	****Illicit Use of Opiate Medication – ever****	****~****	****4.4 million****Resultant Opiate Medication Addiction****	****	****      ?**
**Development of Addiction After Self Exposure**
**	****Alcoholism****	****~****	****1 in 8 to 1 in 15****Cocaine Addiction****	****~****	****1 in 8 to 1 in 15****Heroin Addiction****	****~****	****1 in 3 to 1 in   5**

**Prevalence of Specific Drug Abuse and Vulnerability to Develop Addictions**

***NIDA, SAMHSA Reports, 1998-2005 ***

## Hypothesis (1964)Leading to Development of Methadone Maintenance Treatment

**disease” – of the brain with resultant behaviors of**
**“****drug hunger” and drug self-administration, despite**
**negative consequences to self and others. Heroin**
**addiction is **_**not**_** simply a criminal behavior or due**
**alone to antisocial personality or some other **
**personality disorder.**
** **

**Hypothesis**** (1964)****Leading to Development of Methadone Maintenance Treatment**

***Dole, V.P., Nyswander, M.E. and Kreek, M.J.: Narcotic blockade. ***_***Arch. Intern. Med.***_***, ***_***118***_***:304-309, 1966; 2006***

## Impact of Short-Acting Heroin versus Long-Acting Methadone Administered on a Chronic Basis in Humans - 1964 Study and Opioid Agonist Pharmacokinetics:Heroin Versus Methadone

| Systemic Bioavailability After Oral Administration | 
Apparent Plasma Terminal Half-life (t1/2 Beta) | Major Routeof Biotrans-formation |
| --- | --- | --- |

| Limited
(<30%) | 3min
(30min for active 6-acetyl-morphine metabolite;4-6h for morphine and active morphine-6-glucuronide metabolite) | Successive deacetylation and morphine glucuronidation |
| --- | --- | --- |

| Essentially Complete
(>70%) | 24h
(48h for active [R](l)-enantiomer) | N-demethylation |
| --- | --- | --- |

***Dole, Nyswander and Kreek, 1966; ******Kreek et al., 1973; 1976; 1977; 1979; 1982; Inturrisi et al, 1973; 1984***

## “On-Off” versus “Steady-State”:Relationship Between Blood (and Brain) Levels of Drugs of Abuse and Their Effects on Events Related to Addictions 

**          ****	****•  ****levels of gene expression**
**	****•  ****receptor mediated events**
** ****	****•  ****physiology**
**	****•  ****behaviors**

**“****On-Off” *****versus***** “Steady-State”:****Relationship Between Blood (and Brain) ****Levels of Drugs of Abuse and Their Effects ****on Events Related to Addictions **

**Rates of rise of blood (and presumable brain) levels of drugs of abuse are related positively to their reinforcing effects**
**Rates of fall of blood (and presumably brain) levels of drugs of abuse are related positively to the onset of withdrawal symptoms and/or acute “craving”**

***Kreek, 1978;1987;1991;1992; 2001***

## Methadone Maintenance Treatment for Opiate (Heroin) Addiction

**Efficacy in “good” treatment programs using adequate doses (80 to 150mg/d):**
**     ****Voluntary retention in treatment *****(1 year or more)*****	****50 – 80%**
**     ****Continuing use of illicit heroin****	****	****	****	****  5 – 20%**
**Actions of methadone treatment:**
**     ****•  ****Prevents withdrawal symptoms and “drug hunger”**
**     •  ****Blocks euphoric effects of short-acting narcotics**
**     •  ****Allows normalization of disrupted physiology**
**Mechanism of action:****   Long-acting narcotic provides steady levels of    ****	****opioid at specific mu receptor sites.**
*** ******methadone found to be a full mu opioid receptor agonist which internalizes like endorphins***
*** ******methadone also has modest NMDA receptor complex antagonism)***

**Methadone Maintenance Treatment for Opiate (Heroin) Addiction**

***Kreek, 1972; 1973; 2001; 2005; Inturrisi et al, in progress; Evans et al, 2003***

## Mu Opioid Agonist and Antagonist Pharmacotherapies:Opiate Treatment Outcome* and Numbers Seeking Treatment***

**     ****Methadone Maintenance****	****	****	****	****50 – 80%**
**     ****Buprenorphine-Naloxone Maintenance****	****	****	****40 – 50%****
**Mu Opioid Receptor Antagonists**
**     ****Naltrexone Maintenance****	****	****	****	****10 – 20%**
**Other**
**     “****Drug Free” (non-pharmacotherapeutic)****	****	****  5 – 30%**
**     ****Short-term Detoxification (any mode)****	****	****  ****	****  5 – 20%**

**Mu Opioid Agonist and Antagonist Pharmacotherapies:****Opiate Treatment Outcome* and ****Numbers Seeking Treatment*****

**********	******One year retention in treatment and/or follow-up with significant reduction or elimination of illicit use of opiates***
***** Maximum effective dose (24 to 32 mg sl) equal to 60 to 70 mg/d methadone.  Data based on 6 month follow-up only.***
****** OTR – Pharmacotherapy with methadone or buprenorphine maintenance***

***Kreek, 1996; 2001; 2004; 2006; Treatment Episode Data Set (TEDS), SAMHSA, 2005***

_**OPIATE ADDICTION**_

_**Illicit Opiate Users Seeking Treatment**_

| Numbers | 1995 | 2005 |
| --- | --- | --- |
|    Heroin (%OTR***) | 227,989 | 254,345 (30.1) |
|    Prescription Opiates (%OTR***) |   16,121 |   67,887 (19.9) |

## Natural History of Drug Abuse and Addictions

**Natural History of Drug Abuse and Addictions**

**Initial Use of**
**Drug of Abuse**

**Sporadic**
**Intermittent**
**Use**

**Regular**
**Use**

**Addiction**

**Early**
**Withdrawal**
**(abstinence)**

**Protracted**
**Abstinence**

**WITHOUT PHARMACO-THERAPY, RELAPSE**
**TO ADDICTION***

**>80%**

**SUSTAINED ABSTINENCE***

**<20%**

********with no medications***

**ADDICTION:**** Compulsive drug seeking behavior and drug self-administration, without regard to negative consequences to self or others (adapted from WHO).**

**Primary**
**Prevention**

**Possible Utility of Vaccines**
**and Selected Medications**

**Medications Useful**
**and Needed**

***Kreek et al., ***_***Nature Reviews Drug Discovery***_***, ***_***1***_***:710, 2002; 2007***

**For entry into opioid agonist pharmacotherapy (methadone or LAAM maintenance) (U.S. Federal Regulations), above criteria, plus multiple daily self-administration of opiates for one year or more. For entry into opioid partial agonist pharmacotherapy (buprenorphine),  meeting DSM-IV criteria for dependence.**

## [18F] Cyclofoxy (a Selective Opioid Antagonist) Binding 

**82.50**

**48.75**

**[****18****F] Cyclofoxy (a Selective Opioid Antagonist) Binding **
**in Human Brain: Normal Volunteer PET Study - NIH**

## Mu Opioid Receptor Density in Humans:Specific Binding of [18F] Cyclofoxy (mean + S.E.M.) in 13 Brain Regions of Normal Volunteers and Long-Term, Methadone Treated Former Heroin Addicts  - PET Study

- 8

- 6

- 4

- 2

- 0

- 10

- 12

- 14

- 16

**Thl**

**Amy**

**Caud**

**Ins**

**ACg**

**Put**

**MT**

**MFr**

**Par**

**Crb**

**IT**

**Hip**

**WMt**

**Region of Interest**

**Specific Binding (ml plasma/ml tissue)**

***Kling et al., 2000***

- *

- *

- *

- *

- *

**Normal volunteers n=14**

**MTP volunteers n=14**

**Area related to pain response**

**Dopaminergic terminals of VTA neurons (mesolimbic-mesocortical dopaminergic system regions) **

**Dopamine terminals of substantia nigra neurons**

## Methadone Maintenance Treatment Allows Normalizationof Endogenous Opioid-Related Physiological FunctionsDisrupted During Chronic Heroin Use

**Neuroendocrine Function**
**Hypothalamic-Pituitary-Adrenal Axis**** – ****Stress Responsivity****levels and circadian rhythm of release of POMC peptides****(******** Endorphin; ACTH and cortisol)**
**Hypothalamic-Pituitary-Gonadal Axis**** – ****Reproductive Biology**** levels and pulsatile release of LH and testosterone levels**
**Immune Function**
**Natural Killer Cell Activity**
**Absolute Numbers of Cells**** — T cells; T cell subset levels;****B cells; NK cells**
**Immunoglobin Levels (M and G)**

***Kreek, 1972; 1973; 1978; 1987; 1992; 2001; Novick et al., 1989***

## Factors Contributing to Vulnerability to Develop a Specific Addiction

**use of the drug of abuse essential (100%)**

**Genetic****(25-60%)**
**• ****DNA**
**• ****SNPs**
**• ****other **
**   ****polymorphisms**

**Drug-Induced Effects****(very high)**

**Environmental****(very high)**
**• ****prenatal**
**• ****postnatal**
**• ****contemporary**
**• ****cues**
**• ****comorbidity**
**• ****stress-responsivity**

***Kreek et al., 2000; 2005***

**• ****mRNA levels**
**• ****peptides**
**• ****proteomics**

**• ****neurochemistry**
**•***** *****synaptogenesis**
**• ****behaviors**

## Primary Site(s) of Major Drugs of Abuse

**	****	****	****	****     ****opioid system (mu opioid receptor)**
**	****	****	****	****•    ****Also affects dopaminergic system**
**	****	****	****	****•    ****Enhances dopamine by inhibition of **
**	****	****	****	****      ****inhibitory GABAergic neurons**
**Cocaine****	*****Stimulant*****	****•     Acts primarily on dopaminergic,**
**	****	****	****	****      ****as well as on serotonergic**
**	****	****	****	****      ****and noradrenergic presynaptic reuptake**
**	****	****	****	****      ****transporters**
**	****	****	****	****•     ****Also affects mu and kappa opioid systems**
**Alcohol****	*****Stimulant &*****	****•     Undefined primary site of action**
**	****	*****Depressant*****	****•     Affects dopaminergic, serotonergic**
**	****	****	****	****      ****and opioid systems**

**Primary Site(s) of Major Drugs of Abuse**

***Kreek, 1978, 1987, 2005***

## Reinforcing or “Reward” Effects of Drugs of Abuse

**interpreted by the individual as ****“desirable”**** or ****“pleasurable”****, i.e.,**
**“****rewarding”****. These effects may lead to ****“craving”**** or ****“hunger”**** for **
**the drug, with resultant spontaneous activity or work for ****drug **
**acquisition**** and ****self-administration****.**
**Primary sites of actions of drugs of abuse with respect to their**
**reward or reinforcing effects have been identified as specific **
**brain regions, rich in ****dopamine nerve terminals or cell bodies****, the**
**mesolimbic and mesocortical dopamine systems especially the**
**nucleus accumbens****, as well as the amygdala, the anterior cingulate and the insula, with related actions in the nigrostriatal dopaminergic regions.  ****Each of these areas also has abundant receptors and peptides of the endogenous opioid system.**
** **

**Reinforcing or “Reward” Effects of ****Drugs of Abuse**

***Kreek, 1987; 2005***

## RAT BRAIN

**SNr **

**SNc (A9)**

**VTA (A10)**

**CPU**

**Olfactory Tubercle**

**NAc Shell**

**Amygdala**

**Hypothalamus**

**NAc Core**

**Locus Coeruleus**

**Cingulate**

**Pituitary**

***Modified  by Schlussman (2001) from Paxinos and Watson Lateral 1.40 mm***

**Ventral **
**Pallidum**

**RAT BRAIN**

## Bidirectional-Translational Research:Novel and Conventional Animal Models

- 	(mimics most  common pattern of human use in addiction)
**Pump Methadone Administration Model:**
-    (converts short-acting pharmacokinetic properties of opioid
- 	agonist in rodent to long-acting human pharmacokinetic profile)
**Extended Access Self-Administration Without or With High-Dose Drug **(Cocaine or Opiate)
**“****Binge” Pattern Cocaine Administration Model:**Constant or Ascending Dose
- 	(mimics most common pattern of human use in addiction)
**“****Binge” Pattern Oral Ethanol Administration Model:**
- 	(mimics common pattern of human excessive use)

**Bidirectional-Translational Research:****Novel and Conventional Animal Models**

***Kreek et al., 1987; 1992; 2001; 2005***

## Extended Session (18h) Morphine Self-administration in Rats: Dose Escalation by Choice or No Possible Escalation: Effects on [35S]GTPγS binding in the thalamus and amygdala membranes

***Kruzich, Chen, Unterwald & Kreek, 2001; Kruzich et al, *****Synapse,***** 2003***

## Chronic Intermittent Escalating Dose Morphine and Acute Withdrawal from Morphine: Effects on

**0.0**

**0.1**

**0.2**

**0.3**

**0.4**

**0.5**

**0.6**

**0.7**

**0.8**

******

******

**Lateral hypothalamus**

**Nucleus accumbens core**

*****

*****

**Chronic Intermittent Escalating Dose Morphine and Acute Withdrawal from Morphine: Effects on**
**Mu Opioid Receptor mRNA Levels**

**CONTROL**

**Chronic**
**Morphine**

**Acute**
**Withdrawal**
**from Chronic**
**Morphine**

**CONTROL**

**Chronic**
**Morphine**

**Acute**
**Withdrawal**
**from Chronic**
**Morphine**

## Mu Opioid Receptor-Endorphin System: REWARD —Acute “Binge” Pattern Cocaine Increases Mu Opioid Receptor mRNA Levels and Chronic Cocaine Increases Mu Opioid Receptor Density in Rat

***Yuferov et al., ***_***Brain Res. Bull.***_***, ***_***48***_***:109***** *****1999; ******Unterwald et al., ***_***Brain***_*** ***_***Res***_***., ***_***584***_***:314***** *****1992***

## Increased Mu Opioid Receptor mRNA Levels Induced by Subacute Cocaine Administration (3 Days) are Attenuated or Prevented by Low to Moderate Dose Methadone Infused by Pump in the Rat

**Rats sacrificed 10 days following methadone-filled osmotic pumps; shaded area represents data from control group (n=8) that received no methadone and no cocaine.**
*** Significant difference from same cocaine-dose group in 0-dose methadone maintained group.**

*****

**#**

**#**

**#**

**#**

**Methadone Dose**

***Leri et al., Neuropsychopharmacology, 31:1462, 2006***

## Mu Opioid Receptor Knock-Out Mice

**No morphine or other mu agonist analgesia**
**No heroin or morphine self-administration**
**No heroin or morphine induced conditioned place preference**
**Attenuated self-administration of cocaine**
**Attenuated self-administration of alcohol**

**Reviewed in *****Kreek  et al., ***_***Nature Reviews Drug Discovery***_***, ***_***1***_***:710-726, 2002***

***[Different knock-out constructs and multiple research groups, including Kieffer,  ****** Uhl, Yu. Pintar, Loh, with, e.g., Maldonado, Pasternak, Hoellt, Roberts]***

## Acute Intermittent Morphine IncreasesPreprodynorphin and Kappa Opioid ReceptormRNA Levels in Rat Whole Brain (Minus Cerebellum)

- 200

- 150

- 100

- 50

- 0

**% of Saline Control**

- Saline

- Morphine

*****

**ppDyn mRNA**

- 200

- 150

- 100

- 50

- 0

**% of Saline Control**

- Saline

- Morphine

*****

**KOR mRNA**

***Wang et al., 1999***

**	****Saline**
**	****Morphine****	****6.25 mg/kgx6x1 day**

*******

*******

## Natural Dynorphin A1-17 Lowers Basal and Cocaine Induced Dopamine Levels in Mouse Striatum

***Zhang, Butelman, Schlussman, Ho, and Kreek, ***_***Psychopharmacology***_***, ***_***172***_***:422  2004***

**20-min Sample**

## “Craving” or “Drug Hunger”: Hypothesis(with or without drug seeking and drug self-administration)

**Neurochemical mediators of “rewarding” or “reinforcing” effects of drugs of abuse**
**Dopamine acting at dopamine DA****1****-like and DA****2****-like receptors**
**Mu opioid receptor agonists acting at mu opioid receptors (e.g., beta-endorphin and enkephlins)**
**CRF and ACTH in stimulant and stimulant-depressant addicts only (e.g., cocaine and alcoholism)**
**+/- serotonin, +/- norepinephrine**
**Neurochemical counter-modulators of “rewarding” or "reinforcing" effects**
**Kappa opioid receptor agonists acting at kappa opioid receptors (e.g., dynorphins)**
**Orphanin/nociception acting at orphan opioid-like receptors**
**CRF and ACTH in opiate addicts (e.g., heroin)**
**+/- GABA, +/- glutamate**

**Chronic drug use leads to persistent neurochemical and neurobiological changes, with blunting of the “rewarding” components and persistence of the counter-modulatory components (lowered dopaminergic tone and relative “endorphin deficiency”), which, when coupled with learning and memory, contribute to the resultant “drug craving” and “drug hunger.”**

***Kreek, 2003; 2007***

## Hypothesis — Atypical Responsivity to Stressors: A Possible Etiology of Addictions

**Atypical responsivity to stress and stressors may, in part, contribute to the persistence of, and relapse to self-administration of drugs of abuse and addictions.  Such atypical stress responsivity in some individuals may exist prior to use of addictive drugs on a genetic or acquired basis, and lead to the acquisition of drug addiction.**

***Kreek, 1972; 1981; 1982; 1984;***** *****1987; 1992; 2001; 2005***

**Hypothesis — Atypical Responsivity to Stressors: A Possible Etiology of Addictions**

## Neuroendocrine Effects of Opiates, Cocaine, and Alcohol in Humans:                                    Hormones Involved in HPA Axis Stress Response

**Chronic effects of short-acting opiates (e.g. heroin addiction)**
**Opiate withdrawal effects**
**Opioid antagonist effects**
**Cocaine effects**
**Alcohol effects**
**Chronic effects of long-acting opiate (e.g. methadone****maintenance treatment)**

**Neuroendocrine Effects of Opiates, Cocaine, and Alcohol in Humans:                                    Hormones Involved in HPA Axis Stress Response**

**Suppression of HPA Axis**
**Activation of HPA Axis****Normalization of HPA Axis**

**HPA – Hypothalamic-pituitary-adrenal axis (involved in stress response) **

***Kreek, 1972; 1973; 1987; 1992; 2001; 2003***

## Dissecting the Hypothalamic-Pituitary-Adrenal Axis in Humans:Single-Dose (2.25g) Metyrapone Effects

******-End **** ****(********)**** **

- adrenal

**CRF ****(********)****  **

**POMC**

**Cortisol **** ****(********)**** **

- hypothalamus

**ACTH **** ****(********)**** **

- anterior
- pituitary

**Dissecting the Hypothalamic-Pituitary-Adrenal Axis in Humans:****Single-Dose (2.25g) Metyrapone Effects**

**Endogenous **
**Opioids**
**(mu – inhibition)**
** ****(kappa – ? activation)**

***Kreek, 1973, 1978, 2006; Kreek et al.1984; ***
***Schluger et al, ***_***Neuropsychopharmacology***_***, ***_***24***_***:568, 2001; 2006***

## Metyrapone Testing:a Chemically-Induced “Stress”

**   ****Heroin addicts**
**hyporesponsive**
**   ****Methadone maintained former heroin addicts**
**euresponsive**
**   ****Drug-free, opioid medication-free former heroin addicts**
**hyperresponsive**
**   ****Cocaine addicts- recently abstinent**
**hyperresponsive**
**    ****Cocaine addicted, methadone maintained former heroin      ****	****addicts**
**hyperresponsive**

***Kreek, 1972; 1973; 1984; 1987; 1992; 2005; ***
***Kreek et al., 1984; Schluger et al., 2001 ***

**“****Hyperresponsive” indicates a relative endorphin deficiency**

## Dissecting the Hypothalamic-Pituitary-Adrenal Axis in Humans:Selective Opioid Antagonist Testing

**Opioids**
**(mu – inhibition)**
** ****(kappa – ? activation)**

******-End**

- hypothalamus

- anterior
- pituitary

**POMC**

**Cortisol**

**ACTH**

**CRF **** **

**Opioid****Antagonists**

- adrenal

**Dissecting the Hypothalamic-Pituitary-Adrenal Axis in Humans:****Selective Opioid Antagonist Testing**

***Kreek, 1984; 1998; 2006***

## Single Nucleotide Polymorphisms (SNPs) in Genes: Definitions

**SNP — a single nucleotide polymorphism, that is, one nucleotide or base of any base pair**
**Allelic Frequency:****	**
**     ****<1%****	****low or rare**
**     ****1–5%****	****intermediate**
**      ****>5%****	****high, frequent**

***Hassin and Kreek, 2004***

## Hypothesis – Genetic Variabilityand the Mu Opioid Receptor System: Single Nucleotide Polymorphisms of Moderate Allelic Frequency in the Coding Region 

**	****	****	****	****	****	****	****Allele frequency**
**Variant****	****	****Exon****	****Protein****	****	****Corresponding****	****(overall – 3 ethnicities**
**(nucleotide position)****	****location****	****domain****	****	****amino acid change****	****together) ****	****	****	****	****	****	****	**
**A118G****	****	****1****	****N-terminus****	****Asn 4 Asp (N40D)****	****10.5%**
**	****	****	****	****	****	****	****(26 heterozygous;**
**	****	****	****	****	****	****	****3 homozygous)**
**C17T****	****	****1****	****N-terminus****	****Ala 6 Val (A6V)****	****6.6%**
**	****	****	****	****	****	****	****(14 heterozygous;**
**	****	****	****	****	****	****	****3 homozygous)**

**Hypothesis – Genetic Variability****and the Mu Opioid Receptor System:**** Single Nucleotide Polymorphisms of Moderate Allelic Frequency in the Coding Region **

** Nucleotide position 1 is first base of the start codon.*

***Bond, LaForge... Kreek, Yu, ***_**PNAS**_**, **_**95**_**:9608*****, 1998***

**Some of the individual genetic variability in susceptibility to the development and persistence of, or relapse to, opiate addiction may be due to polymorphisms of the mu opioid receptor. Also, individual differences in responses to endogenous opioids (“physiogenetics”) or pharmacotherapies (“pharmacogenetics”) may be mediated by variant forms of the mu opioid receptor.  **

## Human Mu Opioid Receptor:Location of Coding Region SNPs(SNPs Resulting in Amino Acids Changesor Synonymous Mutation)

***Kreek, LaForge, Yuferov, 2005***

## Binding and Coupling to G Protein-Activated, Inwardly Rectifying K+(GIRK) Channels by Endogenous Opioid Peptides to the Prototype and A118G Variant Mu Opioid Receptor

**100**

**80**

**60**

**40**

**20**

**Percent Bound**

**0**

**1.0**

**0.5**

**Fraction Maximum Current Response**

**0**

**Log [Endomorphin -1(M)]**

**-11**

**-10**

**-9**

**-8**

**-7**

**-10**

**-9**

**-8**

**-7**

**-6**

**100**

**80**

**60**

**40**

**20**

**0**

**Log [******** Endorphin (M)]**

**-11**

**-10**

**-9**

**-8**

**-7**

**A118G**

**Prototype**

***Bond et al., ***_***Proc. Natl. Acad. Sci. USA***_***, ***_***95***_***:9608-9613, 1998***

**1.0**

**0.5**

**0**

**-9**

**-8**

**-7**

**-6**

**Log [Endomorphin -1(M)]**

**Log [******** Endorphin (M)]**

## Physiogenetics and Pharmacogenetics Related to A118G Variant of Human Mu Opioid Receptor Gene

**Physiogenetics and Pharmacogenetics Related to A118G Variant of Human Mu Opioid Receptor Gene**

**Days**

***Oslin et al., 2003 ***

***Wand et al, 2002***

**Basal plasma levels of cortisol significantly higher in persons with the A118G variant.**
***Bart et al, 2006***

## Association Between a Functional Polymorphism in the mu Opioid Receptor Gene and Opiate Addiction and also Alcoholism in Central Sweden

|  | Alcohol Dependent (n=389) | Control (n=170) |
| --- | --- | --- |
| G/G; A/G | 90 | 23 |
| A/A | 299 | 147 |
| 118G Allele Frequency * | 0.125 | 0.074 |

**Thus, in the entire study group in this central Swedish population:****Attributable Risk due to genotypes with a G allele: ****11.1%**** ****(with confidence interval ranges from 3.6 to 18.0%)**

**** ******Overall 118G Allele Frequency = 0.109***

***Bart G , Kreek MJ, LaForge KS... Ott J, Heilig M, ***_***Neuropsychopharmacology***_***, ***_***30***_***:417, 2005***** **

|  | Opiate Dependent (n=139) | Control (n=170) |
| --- | --- | --- |
| G/G; A/G | 41 | 23 |
| A/A | 98 | 147 |
| 118G Allele Frequency  | 0.155 | 0.074 |

***Bart G , Heilig M, LaForge KS... Ott J, Kreek MJ, et al., ***_***Molecular Psychiatry***_***, ***_***9***_***:547-549,*** ***2004***

**Thus, in the entire study group in this central Swedish population:****Attributable Risk due to genotypes with a G allele: ****18%**** ****(with confidence interval ranges from 8.0 to 28.0%)**

## Hypothesis (1998-2000) and Findings (2002-2007) Concerning the Functional A118G Variant of the Mu Opioid Receptor

**One or two copies of the functional A118G variant of the mu opioid receptor gene will result in differences in basal levels of the stress hormone, cortisol, and in stress responsivity, as objectively measured using a specific opioid antagonist (e.g., naloxone, naltrexone, nalmefene).**
**One or two copies of the functional A118G variant of the mu opioid receptor will predict a positive (“good”) outcome to treatment of alcoholism with an opioid antagonist (since we hypothesized and have now shown that alcoholics seek and like modest activation of the stress-responsive hypothalamic-pituitary-adrenal axis).**
**Further, the A118G variant of the mu opioid receptor will be found to be associated with alcoholism and also opiate addiction – two addictive diseases which are characterized by disruption of HPA axis function and alter stress responsivity.**

***Bond et al, 1998; Kreek, 1999; LaForge, 2000; Kreek et al., *****Nature Neuroscience*****, 2005; 2007***

## LABORATORY OF THE BIOLOGY OF ADDICTIVE DISEASES, 2007

***BACK ROW: ******	******Marek Mandau, Caitlin Smith*****, *****Melanie Johncilla, Matthew Swift, Kitt Lavoie,******	******Susan Russo, Johannes Adomako, Julia Allen, Kimberly O’Hara, Laura Nunez***

***MIDDLE ROW: ******	******Morgane Rouault, Dmitri Proudnikov, Brenda Ray, Anne Dalton, Lisa Borg, ******	******Yong Zhang, Roberto Picetti, Brian Reed, Matthew Randesi***

***FRONT ROW: ******	******Orna Levran, Elizabeth Khuri, Vadim Yuferov, David Nielsen, Ann Ho, Mary Jeanne Kreek,***** *****	******Eduardo Butelman, Yan Zhou, Stefan Schlussman, K. Steven LaForge***

**LABORATORY OF THE BIOLOGY OF ADDICTIVE DISEASES, 2007**
**Mary Jeanne Kreek, MD – Professor and Head**