NS 24 - substance abuse

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Substance abuse lecture
Erica Lai
Flashcards by Erica Lai, updated more than 1 year ago
Erica Lai
Created by Erica Lai almost 6 years ago
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Question Answer
what is tolerance? the capacity of the body to endure or become less responsive to a substance especially with repeated use or exposure
what is physical dependence? caused by chronic use of a tolerance-forming drug of which abrupt cessation results in unpleasant symptoms
dependence syndrome means when you need the drug to be present to maintain normal function
what are the 2 types of withdrawal syndrome? acute withdrawal that lasts for days protracted withdrawal syndrome which means the person experiences cravings for years after detox
what is withdrawal brought about by (4) abrupt cessation rapid dose reduction decreasing blood level of drug administration of an antagonist
what is addiction? the intense desire to obtain increasing amounts of a substance(s) over all other activities it is a chronic, neurobiological disease with genetic, psychosocial, and environmental factors
addiction behaviour is characterised by (4) compulsive use of substance drug seeking behaviour continued use despite physical, social, and economic harm high tendency to relapse
what reward pathway do all drugs of abuse activate? outline the structures involved in this pathway mesolimbic dopamine pathway comprises ventral tegmental area (VTA) which is connected to the ventral striatum by dopamine neurons. the nucleus accumbens (NAc) and the olfactory tubercle make up the ventral striatum.
what is the effect alcohol has on the CNS and how does it achieve this effect? alcohol is a CNS depressant it acts on GABAaRs to increase inhibitory transmission (it also enhances the CNS depressant effects of other drugs)
acute alcohol effects include increase in GABAaR activity --> cellular hyperpolarisation decrease Ca conductance via NMDA recetpors --> decrease depolarisation
outline how neuroadaptation in chronic alcoholism occurs overtime, the body internalises normal alpha 1 GABAaRs and increases the expression of 'low alcohol sensitivity' alpha 4 GABAaRs NMDA receptors are phosphorylated and so there will be less on the cell surface
name some of the effects/symptoms of chronic alcoholism (6) fatty liver disease impaired testicular steroid synthesis --> feminisation and impotence pseudo-cushing's syndrome chronic gastritis because alcohol destroys the gastric mucosa peripheral neuropathy dementia, motor impairment because of cerebral cortex thinning and degeneration of cerebellum
outline what happens, on a cellular level, in alcohol withdrawal syndrome decreased inhibitory GABA transmission and increased excitatory glutamate transmission ---> CNS hyperactivity
outline symptoms of alcohol withdrawal syndrome in the first 24 hours you get sweating, tremor, fever, sometimes hallucinations then you get seizures, agitation, aggresesion, severe hallucinations delrium tremens (onset on the 3rd day) is a medical emergency: delirium, hallucinations, course tremor, disorientation, hyperthermia, seizures
treatment for acute alcohol withdrawal long-acting benzodiazepines (chloradiazepoxid) + haloperidol (adjuvant) prenteral thiamine if suspected/confirmed wernicke's korsakoff syndrome
treatment options to aid abstinence from alochol disulfiram = acetylaldehyde dehydrogenase inhibitor --> accumulation of acetylaldehyde when alcohol is consume giving unpleasant effects: flushing, headache, nausea, vomiting acamprosate = NMDA receptor antagonsist and GABA agonist (helps with CNS hyperactivity and decreases craving) naltrexone = opiate antagonist that reduces the reinforcing effects of alcohol also pancreatic enzyme supplementation, high dose oral thiamine
name 3 opioids heroin morphine codeine
outline cellular effects of acute opioid use activation of mu receptors --> increase K conductance + inhibit adenylyl cyclase --> cellular hyperpolarisation
outline how neuroadaption occurs with prolonged opioid use tolerance to eurphoria is due to: increase of mu receptor phosphorylation leading to internalisation and degration decreased efficacy of mu opioid signal transduction hyperactivation of adenylyl cyclase signaling --> enhanced GABA action
what happens on a cellular level when you go through opioid withdrawal? enhanced GABA action inhibits VTA dopamine neurons leading to dysphora and anhedonia
what is the meaning of anhedonia? unable to feel pleasure in normally pleasurable activities
treatment of opioid overdose naloxone (a synthetic opioid receptor antagonist)
3 drugs used in opioid detoxification methadone - decreases withdrawal symptoms without producing a high buprenorphine - partial mu receptor agonist that prevents withdrawal symptoms by blocking the actions of other opioids clonidine - alpha 2 noradrenergic agonist that decreases autonomic overactivity and thereby decreases withdrawal
benzodiazepine MOA increase frequency of Cl channels opening in response to GABA and GABAaRs leading to increased neuronal inhibition
dependence on benzodiazepines can develop during long-term clinical use, so... only short courses (2-3 weeks) recommended discontinue with tapered dose
withdrawal of benzodiazepines is associated with (3) rebound anxiety insomnia seizures
nicotine targets which receptor? nicotinic AChRs located centrally and peripherally and at NMJs
how does nicotine activate the dopamine reward pathway? activating AChRs on dopaminergic neurons in VTA to increase dopamine release
activation of central nicotinic receptors produces anxiolytic effects increased arousal appetite suppression
activation of peripheral nicotinic receptors produces increased BP increased smooth muscle contraction
smoking cessation treatment: buproprion an antidepressant that increases dopamine and NA pathways in CNS
smoking cessation treatment: varenicline partial agonist at alpha 4 beta 2 AChR - decreases craving and pleasurable effects of cigarettes
what is the primary mechanism of action for psychostimulants augment the effects of dopamine
examples of psychostimulants (4) cocaine amphetamine methamphetamine cannabinoids
active compound in cannabinoid delta 9 tetrahydrocannabinol (THC)
what receptors do cannabinoids act on G-couple proteins: CB1 (brain) CB2 (immune cells)
name 2 hallocinogens LSD MDMA
where does LSD come from mushrooms (ergot)
how does MDMA work? increase serotonin release and blocks erotonin reuptake
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