1. Jon-Kar Zubieta, M.D., Ph.D. Phil F. Jenkins Professor of Psychiatry Professor Departments of Psychiatry, Radiology, and Neurosciences Program Research Professor Molecular and Behavioral Neuroscience Institute The University of Michigan Smoking Effects on Dopamine and Opioid Neurotransmission in Humans Is it just the nicotine ?

2. Complex Effects of Nicotine on Brain Functional Measures Acute effects on glucose metabolism, regional cerebral blood flow and BOLD responses in distributed networks: –Thalamus (high concentration of nicotinic receptors) (Domino et al., 2000a,b; Zubieta et al., 2001, 2005; Rose et al., 2003). –Cognitive/attentional regions: DLPFCTX, temporo-parietal cortex (Xu et al., 2005, 2006; Han et al., 2007; – Motivational/reward regions: Nucleus accumbens, amygdala, medial prefrontal and anterior cingulate cortex. Both increases (Stein et al., 1998) and reductions in some of these regions (Zubieta et al., 2001, Rose et al., 2003). Directionality of the effects may depend on the status of the individual (e.g., satiation, withdrawal). Effects also appear influenced by method of administration (nasal spray, i.v., smoking)

3. rCBF responses to 1st cigarette baseline vs. nicotinized (1.01 mg) Zubieta, Heitzeg et al., 2005

4. rCBF responses to 1st cigarette nicotinized vs. denicotinized (0.08 mg) Zubieta, Heitzeg et al., 2005

5. rCBF responses to 2nd cigarette 2nd nicotinized vs. denicotinized Zubieta, Heitzeg et al., 2005

6. Monoamine-Opioid Systems may Mediate Drug Effects

7. Evidence of DA Release in vivo Reductions in basal ganglia DA D2/3 receptor availability in non-human primates after i.v. nicotine (PET and 11 C-raclopride) (Marenco et al., 2004) Similar results in humans, before and after smoking, selective to the ventral basal ganglia (Brody et al., 2004), further influenced by genetic polymorphisms thought to influence DA function (i.e., DAT, DRD4, COMT) (Brody et al., 2006) Negative results -no significant change in receptor availability- using nicotine nasal spray, but individual changes showed relationships with subjective ratings of drug effect (Montgomery et al., 2007)

8. Effects on Opioid Neurotransmission? Tobacco smoking and craving may be ameliorated by opioid antagonists (Karras and Kane 1980), with inconsistent effects in later reports (reviewed in Aceto et al., 1993; Pomerleau 1998). Evidence of nicotine-induced alterations in opioid peptide content (protein and mRNA) (Houdi et al., 1991; DiChiara, 2000)

9. Mu Opioid Receptor-Mediated Neurotransmission AMY CAU/ NAC/ VP THA CING 4 3 2 1 BP Distributed in “affective / motivational circuits” - neuronal nuclei involved in responses to rewarding and salient stimuli.

10. Receptor Quantification with PET Tracer Transport (rCBF x Tracer Extraction) Incorporation to Specific Binding Sites 1 min2 min3 min5 min Data Analysis 10 min30 min70 min Generation of Parametric Maps e.g., Logan Plots (K 1, DVR) Coregistration with Anatomical MRI Non-Linear Anatomical Standardization (ICBM Coordinates) STATISTICAL PARAMETRIC MAPS OF SIGNIFICANCE (SPM) 4 3 2 1 Z- VALUE

11. Mu Opioid Neurotransmission Experimental evidence (animal models and humans) and transgenic models implicate them in: –Endogenous opioid analgesia and effects of opiates –Stress responses and stress-induced analgesia –Regulation of affiliative behavior and responses to novelty –Regulation of amygdala and nucleus accumbens-mediated responses to salient stimuli, including drugs of abuse –Thought to mediate placebo effects during expectation of analgesia Direction of modulation is typically suppressive of the relevant response (e.g., pain, stress, anxiety, …)

12. Experimental Design Pilot Study time 0 0 90 40 time 090 40 Baseline DenicotinizedNicotine Randomized Counterbalanced time 090 40 Baseline 11C-Raclopride 11C-Carfentanil Randomized Counterbalanced DenicotinizedNicotine 11C-Raclopride 11C-Carfentanil Scott et al., 2006 Non-Smokers Smokers

13. Scott et al., 2006 Subjects, Plasma Levels ng/mL

14. µ-Opioid Receptor BP smokers vs. non-smokers baseline differences

15. Nicotine-Induced Activation denicotinized vs. nicotinized DopamineOpioid

16. Tobler et al., Science 307: 1642 (2005) Dopaminergic cells respond bidirectionally to predicted reward value and deviations from predictions Effects of Expectancy?

17. McBride et al., 2006: neural responses to cigarette cues were strongly modulated by the expectancy of smoking immeditely after the scan. Thalamo-cingulate connectivity (possibly arousal related) was greater during expectancy than non-expectancy.

18. (Scott et al.,Arch Gen Psychiatry, in press) Placebo Effects

19. (Scott et al.,Arch Gen Psychiatry, in press) Nucleus accumbens dopamine release accounted for 25% of the variance in the formation of placebo analgesic effects Placebo Effects

20. Revised Design Ongoing Study time 0 0 90 40 time 090 40 Baseline Denicotinized Nicotine time 090 40 Baseline 11C-Raclopride 11C-Carfentanil Randomized Denicotinized Nicotine 11C-Raclopride 11C-Carfentanil Scott et al., 2006 Day 1 Day 2

21. Conclusions We show evidence of both dopamine (D2/3 receptors) and opioid (µ-opioid receptors) release during cigarette smoking. Dopamine responses were localized in the nucleus accumbens/ventral basal ganglia. Opioid activation in the rostral anterior cingulate cortex Comparisons with healthy subjects show lower µ-opioid receptor availability during denicotinized condition that was reversed during nicotine condition. These effects were observed in the medial thalamus, nucleus accumbens and amygdala. These regions are known to respond to expectancies (e.g., placebos). Effects of smoking on central neurotransmission may then reflect both pharmacological and cognitive-emotional assessments.

22. The Team … PAIN MODELS Christian S. Stohler, DDS, PhD RADIOCHEMISTRY Michael A. Kilbourn, PhD RADIOTRACER KINETIC MODELING Robert A. Koeppe, PhD REPRODUCTIVE ENDOCRINOLOGY Yolanda R. Smith, MD, MS NEUROENDOCRINOLOGY Elizabeth A. Young, MD fMRI Douglas Noll, PhD Luis Hernandez, PhD STATISTICAL MODELS Thomas Nichols, PhD WARPING METHODS Charles R. Meyer, PhD GENOTYPING David Goldman, MD Margit Burmeister, PhD PROGRAMMING POST-DOCTORAL FELLOWS Alison Berent-Spillson, PhD David Hsu, PhD Tal Shafir, PhD Brian Mickey, MD (Research Track Resident) Yunhai Qiu, MD, PhD GRADUATE STUDENTS Tiffany M. Love David J. Scott Catherine Evans NURSING Virginia M. Weinberg, RN, MS RESEARCH ASSOCIATES Christine Egnatuk, BS Wendy Yau, BS Work presented supported by R01 DA 16423, R01 DA 18974, R01 AT 1415 Heng Wong, PhD JUNIOR FACULTY Mary M. Heitzeg, PhD Scott Langenecker, PhD Carol Persad, PhD Richard Harris, PhD … and the technologists of the PET Center and fMRI Laboratory Kathie Singer, RN

23. Behavioral Phenotypes StressorsSex Hormones Uncontrolled Drug Use  striatal DA response to drug PFC dysregulation  DA to PFC  PFC suppression of Amygdala  Amygdala function  Striatal function Drug ExposureContinued Drug Use  PFC function  Amygdala function Cross-sensitization to substance use Impulse Control Dysregulation Emotional Dysregulation Males more vulnerable to addiction Dysregulation of HPA axis Genetic Variations