Raymond Gan Veeral Gohil Vincent Lam Victoria Leung

1. Parkinson’s Disease and Heroin Raymond GanVeeralGohil Vincent Lam Victoria Leung PHM142 Fall 2012 Coordinator: Dr. Jeffrey Henderson Instructor: Dr. David Hampson

2. Overview • Parkinson’s Disease • Overview and Symptoms • General Information for Parkinson’s Disease • Molecular Mechanism • Pathophysiological Mechanism • Heroin • Overview • Routes of Administration/mechanism • Short term and Long term effects • Heroin’s Connections with Parkinson’s • Treatments

3. Parkinson’s Disease- Overview What is Parkinson’s Disease? • Neurodegenerative disease that affects the part of brain that controls movement (substantianigra) Symptoms: • Tremors (most common and noticed symptom) • Muscle rigidity • Changes in speech and movement • Stiff and aching muscles

4. Parkinson’s Disease- General Exact cause is unknown Substantianigracoordinates movement Parkinson’s Disease causes dopamine-producing cells in the substantianigra to die

5. Parkinson’s Disease- Molecular Mechanism • General: misfoldedα-synuclein leads to oxidative stress. Based on Paraquat (PQ)-based models, proven that NOX1 modulates α-synuclein expression and aggregation of dopaminergic neurons. • Study used Paraquat (a neurotoxin responsible for dopaminergicneurodegeneration in substantianigra) • -> Diagram beside: B- actin is the control. When cells exposed to PQ, increase in α-synuclein • Proves that α-synucleinis involved in neuronal toxicity

6. Parkinson’s Disease- Molecular Mechanism Cont. Used a lentivirus-mediated NOX1 shRNAoverexpression to knock down NOX1. PQ-induced α-synuclein aggregation was lower in cells with overexpressed NOX1 shRNA. (2.5 fold decrease) Summary: NOX1 responsible for mediation of PQ-mediated oxidative stress.

7. Parkinson’s Disease- Pathophysiological Mechanism Misfolded α- synuclein and oxidative stress impacts PD. α- synuclein activates microglia which increases the antioxidant enzyme expression. Mediated though by Nrf2. Microglia are the immune cells in the brain that respond to changes in the brain’s environment. A) coiled structure α-synuclein= inactivated microglia. B) Misfolding. Protofibrils stabilized by dopamine. Increased microglial expression of antioxidant enzymes. Proinflammatory response C) α- synuclein fibrils directly activate proinflammatory pathway. These cells become toxic to neurons surrounding it. Oxidative stress -> activated microglia->increased dopamine neuron dysfunction.

8. Heroin What is Heroin? • An opiate drug synthesized from morphine • a naturally found substance in Asian opium poppy plant • white or brown powder • Depressant of the CNS • Used in clinical setting or recreational purposes http://www.digitalburg.com/artman2/publish/Warrensburg_Police_Dept_34/St_Louis_suburb_hit_hard_by_heroin_deaths.shtml

9. Heroin Heroin Routes of Administration: • Usually taken in ways where it can be delivered to brain quickly • Injected into bloodstream • Snorted through nose • Inhaled/Smoked • Basic amine: nitrogen group • Although mostly ionized at physiological pH, can cross BBB very readily and rapidly • Enters brain where converted to morphine Morphine

10. Heroin Heroin Routes of Administration: • Usually taken in ways where it can be delivered to brain quickly • Injected into bloodstream • Snorted through nose • Inhaled/Smoked • Basic amine: nitrogen group • Although mostly ionized at physiological pH, can cross BBB very readily and rapidly • Enters brain where converted to morphine Morphine

11. Heroin • Binds to opioid receptors in various parts of brain and body • Binding site for all opiate drugs (ie. Cocaine, codeine) and endorphins • Active ingredient of all opiate drugs is morphine • Structurally similar to endorphins (“feel good” chemicals) morphine endorphin

12. Heroin • Opioid receptors responsible for pain perception and activation of pleasure centres in brain related reward • When morphine bound to receptor, prevents pain signals from reaching brain and supresses CNS morphine endorphin

13. Heroin Short-term effects: • Causes users to enter euphoric state • Impaired cognitive abilities • Dry mouth • Heaviness of extremities • Followed by drowsy state • Breathing and cardiac function begins slowing down

14. Heroin Long-Term Effects: • Addiction: user becomes physically dependent on drug • Body becomes tolerant, resulting in physiological response to drug to decrease • More heroin needed to have same effect • Will enter withdrawal state if user stops or reduces use • Restlessness, insomnia • Extreme craving for drug, often resulting in relapse

15. Heroin Long-Term Effects: • Fatal overdose • Liver and kidney disease • Pneumonia: result of effects of heroin on respiration • Permanent damage to vital organs (eg. Lungs, brain)

16. Heroin and Parkinson’s How was the connection found? - Initially, they thought there was no connection between the two, but in 1982, they found a heroin addict that exhibited Parkinsonian symptoms. This was atypical because Parkinson’s Disease mostly affects older people. Discovered that these symptoms were a result of the abuse of synthetic heroin

17. Heroin and Parkinson’s • Synthetic Heroin • 1-methyl-4-phenyl-4-propionpiperidine OR MPPP • Has similar effects on body as heroin • Used more commonly as more easily synthesized and accessible • However, the synthesis of MPPP also produces a by-product, known as MPTP • 1-methyl-phenyl-1,2,5,6-tetrahydropyridine • Major impurity of reaction • Cause of Parkinsonian symptoms in synthetic heroin users

18. Mechanism of MPTP • MPTP converted to MPP+ by monoamine oxidase • MPP+ extremely toxic to dopaminergic neurons in substantianigra • Causes dopamine releasing neurons to die, resulting in difficulty in controlling movement

19. Mechanism of MPTP MPTP BBB MPP+ ETC ROS MAO-B Dopaminergic neurons of substantianigra Cell death & Parkinsonian Symptoms

20. Possible Treatments of Parkinson’s • No cure for Parkinson’s. Only medications to decrease severity of symptoms. • MAO B Inhibitors • Inhibit the action of monoamine oxidase in the breakdown of dopamine • Results in an increased concentration of dopamine, leading to anti-Parkinson’s disease outcomes • Examples: Rasagiline, Selegiline • COMT Inhibitors • Inhibit the action of catechol-O-methyl transferase in the breakdown of dopamine • Results in an increased concentration of dopamine, leading to anti-Parkinson’s disease outcomes • Examples: Entacapone, Tolcapone • Dopaminergic precursors • Precursors molecules that are converted into dopamine • An effective therapy for the initial treatment for Parkinson’s Disease • Examples: Levodopa, carbidopa, Tyrosine, Phenylalanine

21. Possible Treatments of Parkinson’s (Cont) • Dopamine Agonists • Mimics function of dopamine • Binds to post-synaptic dopamine receptors in the absence of dopamine • Examples: Apomorphine, Ropinrole, Bromocriptine, Pramipexole • Anticholinergics • Competitively inhibit muscarinic receptors • Used to help alleviate tremors • Examples: Benztropine, Ethoprpazine, Procyclindine, Trihexyphenidyl

22. Treatment of Heroin • Only medications to prevent relapse and dependency on heroin such as: • Methadone- binds to same receptors as heroin. When taken orally, has sustained effects reducing desire for heroin. Prevents withdrawal symptoms • Buprenorphine- similar mechanism to methadone but has less risk for overdose • Naltrexone- Not as widely used because of poor patient compliance. Blocks opioids from binding to receptors. Users cannot feel effects

23. Summary • Parkinson’s Disease: symptoms: tremors, muscle rigidity, problems with speech • General cause is the degeneration of dopamine producing cells in the Substantianigra • Proven that α-synuclein is directly related to Parkinson’s Disease • Molecular level: In the misfolding of α-synuclein producing oxidative stress, the role of NOX1 (NADPH oxidase) is a very important factor in the reactive oxygen species (ROS) stress. Based on Paraquat-based models, it is proven that Nox1 modulates α-synuclein expression and aggregation in dopaminergic neurons. • Pathophysiological level: α- synuclein activates microglia which increases the antioxidant enzyme expression leading to increased dopamine neuron dysfunction. This mechanism is modulated by Nrf2. • Heroin: opiate drug synthesized from morphine; depressant of CNS • Converted to morphine when enters brain binds to opioid receptors • causes impaired cognitive abilities, and slowed breathing and cardiac function • With regular use, become addicted and body becomes physically dependent on drug • can lead to fatal overdose, pneumonia , and permanent damage of vital organs • Connection between PD and Heroin: • MPTP is a neurotoxic precursor byproduct of synthetic heroin production • Acted on by MAO-B to form neurotoxin MPP+ • MPP+ damages ETC of dopaminergic neurons causing increase in ROS =>eventual cell death and onset of parkinsoniansymptoms • Treatments that help alleviate symptoms of Parkinson’s • MAO B and COMT inhibitors : drugs that inhibit enzymatic actions of MAO, help reduce the degradation of dopamine, • Dopaminergic precursors: drugs converted into dopamine for use in the brain. Main treatment in initial Parkinson’s • Dopamine agonists: drugs that mimic dopamine’s effect on post-synaptic dopamine receptors • Anticholinergics: antagonists of muscarinic receptors, reducing neurotransmission of acetylcholine. Used to decrease tremors

24. References Cristovao, A.C. (2012) NADPH Oxidase 1 Mediates α-synucleinopathy in Parkinson’s Disease. The Journal of Neuroscience, 32 (42), 14465-14477. doi: 10.1523/jneurosci.2246-12.2012 Beraud, D. 2012. Microglial Activation and Antioxidant Responses Induced by the Parkinson’s Disease Protein α-synuclein. J NeuroimmunePharmacol. doi: 10.1007/s11481-012-9401-0 http://www.google.ca/imgres?um=1&hl=en&sa=N&rlz=1C1SNNT_enCA392CA394&biw=1092&bih=514&tbm=isch&tbnid=5gSk7eD50RZyBM:&imgrefurl=http://bio349.biota.utoronto.ca/20089/20089bio349graham/parkinsons/index.html&docid=-SQjGzhFvgddfM&imgurl=http://bio349.biota.utoronto.ca/20089/20089bio349graham/parkinsons/images/intro.jpg&w=250&h=412&ei=QiWYUKicIYrlyAGU8oCYBA&zoom=1&iact=hc&vpx=562&vpy=115&dur=1780&hovh=288&hovw=176&tx=101&ty=122&sig=116721997777392201827&page=1&tbnh=148&tbnw=91&start=0&ndsp=12&ved=1t:429,r:3,s:0,i:118 http://www.google.ca/imgres?um=1&hl=en&sa=N&rlz=1C1SNNT_enCA392CA394&biw=1092&bih=514&tbm=isch&tbnid=b_wa2pZIamGIDM:&imgrefurl=http://www.anti-agingfirewalls.com/2012/06/30/a-stem-cell-cure-for-parkinsons-disease-so-close-and-yet-so-far-away/&docid=_Zr8PaLX3Hd-BM&imgurl=http://www.anti-agingfirewalls.com/__oneclick_uploads/2012/06/dopamine1.jpg&w=252&h=280&ei=QiWYUKicIYrlyAGU8oCYBA&zoom=1&iact=hc&vpx=101&vpy=176&dur=2985&hovh=224&hovw=201&tx=113&ty=127&sig=116721997777392201827&page=1&tbnh=140&tbnw=123&start=0&ndsp=12&ved=1t:429,r:6,s:0,i:127 Rzepa, H. (2011). “Morphine and heroin”. http://www.ch.ic.ac.uk/rzepa/mim/drugs/html/morphine.htm London, E. (2011). “Heroin in the brain- its chemistry and effects”. http://www.pbs.org/wgbh/pages/frontline/shows/heroin/brain/ National Institute of Drug Abuse. (2010). “Heroin”. http://www.drugabuse.gov/publications/drugfacts/heroin

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