The Effects of Alcohol on the Brain

THE EFFECTS OF ALCOHOL ON THE BRAIN LIKE OTHER DRUGS OF ABUSE, ALCOHOL IS ONE OF ONLY 2% OF CHEMICAL COMPOUNDS ABLE TO CROSS THE BLOOD-BRAIN BARRIER-THE BRAIN'S NATURAL LINE OF DEFENSE • Alcohol can do this because it is a small and lipid-soluble molecule, while larger molecules are unable to pass through • This gives alcohol the unique ability to directly impact brain cells, which is an inherent aspect of its popularity as a substance of abuse SHORT-TERM EFFECTS EVEN IN SMALL TO MODERATE DOSES, ALCOHOL HAS A PROFOUND EFFECT ON NEUROTRANSMITTERS IN THE BRAIN: • Neurotransmitters are the chemical messengers that relay information between brain cells (neurons) and their receptors • By affecting certain neurotransmitters, alcohol has the ability to alter numerous brain functions ALCOHOL AFFECTS SEVERAL MAJOR NEUROTRANSMITTERS GABA GABA is the main inhibitory neurotransmitter in the brain. • Alcohol increases the inhibitory effect of GABA by binding to GABA receptors • This reduces overall brain activity and induces sedation. Glutamate • Alcohol inhibits the brain's primary excitatory neurotransmitter, glutamate, particularly at the NMDA glutamate receptor. • This works to further reduce neural activity in the brain. Dopamine • Dopamine is best known for its role in the reward pathways of the brain and the executive functions of the brain's frontal lobe. • Alcohol increases the amount of dopamine in the brain, which reduces inhibitions and makes drinking alcohol rewarding. Serotonin • Alcohol also increases serotonin production in the brain, which affects a person's mood, making him or her feel happy and more relaxed. BY ALTERING THE EFFECT AND CONCENTRATION OF CERTAIN NEUROTRANSMITTERS, ALCOHOL CAUSES WIDESPREAD EFFECTS ON THE HUMAN BRAIN. FRONTAL LOBE HIPPOCAMPUS • The frontal lobe of the brain control executive functions, such as attention, short-term memory • The hippocampus is responsible for storing and encoding short-term memories into long-term memories • By altering GABA and NMDA glutamate receptors, alcohol disrupts hippocampal function • This stops the formation of new long-term memories • Rather than "forgetting" events after a night of drinking, your brain never committed them to memory in the first place and motivation • Alcohol works on GABA receptors in the frontal lobe, lowering a person's inhibitions • Modulation of dopamine receptors in frontal lobe areas reinforces addictive behaviors • Inhibits sensory information and generally makes it difficult to think clearly • Increases reaction time FRONTAL LOBE HIPPOCAMPUS MEDULLA CEREBELLUM RETICULAR ACTIVATING SYSTEM MEDULLA RETICULAR ACTIVATING SYSTEM CEREBELLUM • The Reticular activating system (RAS) is a • The medulla is a part of the brain that regulates essential life functions such as heart rate, body temperature and breathing • The medulla is also affected by changes in GABA and NMDA glutamate receptors, • The cerebellum is responsible for motor coordination By altering GABA receptors, the function of the cerebellum is cluster of connected nuclei that control the sleep-wake cycle in humans • As alcohol alters GABA and NMDA glutamate receptors, activity in the RAS is reduced • This makes initially falling asleep easier, reduced This leads to reduced coordination, which causes lowered heart rate and however that effect rebounds as alcohol loss of balance, reduced motor learning and slurred speech metabolizes overnight The initial sleep stage is deeper, but the second half of sleep is lighter respiratory depression • Too much alcohol also causes the medulla to trigger the vomiting reflex • If the depressive effect of alcohol on the medulla is too great, the person will stop breathing and die LONG-TERM EFFECTS THE SHORT-TERM EFFECTS OF ALCOHOL ON THE BRAIN ARE NUMEROUS, BUT ARE GENERALLY REVERSIBLE. LONG-TERM ALCOHOL ABUSE, HOWEVER, CAN CAUSE IRREVERSIBLE BRAIN DAMAGE, SUCH AS: • Fundamental changes in glutamate and dopamine pathways in the brain • Inhibited formation of new brain cells Contrary to popular belief, alcohol itself does not kill brain cells • Decreased white matter tracts-strong connections between brain cells CHRONIC ALCOHOL ABUSE CAN ALSO RESULT IN WERNICKE-KORSAKOFF SYNDROME, CAUSED BY A DEFICIENCY IN THIAMINE IN THE BRAIN AND BODY • Without enough thiamine, neurons atrophy and die. • Neuronal lesions can occur in the brainstem, hypothalamus, medulla, and across the cerebral cortex, causing problems with muscle movements, breathing and consciousness and inducing an overall state of confusion • Neurons in the hippocampus are especially susceptible, causing severe amnesia, confabulation and general apathy MIRAMAR GETTING WELL STAYING WELL Information From: https://www.scripps.edu/newsandviews/e_20020225/koob2.html /www.ncbi.nlm.nih.gov/pubmed/15704345 http://pubs.niaaa.nih.gov/publications/arh21-2/114.pdf http://thebrain.mcgill.ca/flash/i/i_03/i_03_m/i_03_m_par/i_03_mpar_alcool.html https://kin450-neurophysiology.wikispaces.com/Alcohol+%26+Cerebellum http://pubs.niaaa.nih.gov/publications/arh27-2/186-196.htm http://pubs.niaaa.nih.gov/publications/arh25-2/101-109.htm http://www.todayifoundout.com/index.php/2010/10/alce http://pubs.niaaa.nih.gov/publications/aa63/aa63.htm http://www.eurekalert.org/pub_releases/2014-11/ace-cai111114.php https://en.wikipedia.org/wiki/Long-term_impact_of_alcohol_on_the_brain -does-n -kill-brain-cells/ 00