Neurobiology of Drug Addiction 2022 PDF

REWARD & PLEASURE NEUROBIOLOGY OF DRUG ADDICTION Lecture Objectives Able to describe neurotransmitters that are directly or indirectly responsible for generating feelings of pleasure and reward Able to explain the role of reward pathway in the pathogenesis of drug addiction Able to desc...

REWARD & PLEASURE NEUROBIOLOGY OF DRUG ADDICTION Lecture Objectives Able to describe neurotransmitters that are directly or indirectly responsible for generating feelings of pleasure and reward Able to explain the role of reward pathway in the pathogenesis of drug addiction Able to describe the psychosocial manifestations and medical complications of drug addiction Neuronal cells http://mrallenappsych.weebly.com/uploads/2/0/4/5/20451405/3977436.gif?409 https://www.youtube.com/watch?v=7VUlKP4LDyQ The Reward Pathway https://www.youtube.com/watch?v=NQBoNcr8qIk&t=277s Brain Reward System 1. Mesolimbic pathway 2. Mesocortical pathway 3. Hypothalamus Brain Reward System 1. Mesolimbic pathway reward, attention, learning, memory 2. Mesocortical pathway emotion, motor function 3. Hypothalamus motivated behaviours e.g. food, sex Dopamine Hypothesis of Addiction Under physiologic conditions, the mesolimbic dopamine signal represent a learning signal responsible for reinforcing constructive behavioural adaptation. Addictive drugs generate a strong but inappropriate learning signal. This causes pathologic reinforcement and leads to compulsive behaviour. Serotonin/5-HT E.g. LSD, a serotonin agonist, produces hallucination experiences Different MoA of drugs https://www.youtube.com/watch?v=NQBoNcr8qIk&t=277s The Problem Is drug addiction considered a disease? Initial drug use might be voluntary. What happens later? Drugs of abuse have been shown to alter gene expression and brain circuitry, which in turn affect human behaviour Once addiction develops, these brain changes interfere with an individual’s ability to make voluntary decisions, leading to compulsive drug craving, seeking and use Health Complications https://americanaddictioncenters.org/health-complications-addiction https://www.youtube.com/watch?v=pe5loX720Rk Different classes of addictive substances and their pharmacology I TOBACCO & NICOTINE Lecture Objectives Able to describe pathophysiology/neurobiology of nicotine addiction Able to understand nicotine withdrawal symptoms Able to explain health complications related to smoking and nicotine Smoking in Malaysia Nicotine Alkaloid found in tobacco plant Major psychoactive (addictive) component of tobacco Agonist at nicotinic acetylcholine receptors Nicotine Metabolism Quantitatively, the most important metabolite of nicotine in most mammalian species is cotinine In humans, about 70 to 80% of nicotine is converted to cotinine Cotinine : indicator of smoking or https://www.pharmgkb.org/pathway/PA2011 tobacco smoke exposure https://www.youtube.com/watch?v=cZ3a0m7zTcI Vape @ E-cig https://www.webmd.com/connect-to-care/vaping/what-is-vaping Vape Statistics Is Vape Safe? Genetic Association https://www.frontiersin.org/articles/10.3389/fpubh.2021.664748/full Smoking Toxicity Nicotine Toxicity Homework for tutorial 1. Mini debate – Is Vape Safe? 2. Revise on today’s topics