Download Drugs and Alcohol affects on the brain

Drugs of Addiction and Alcohol
Effects on the Brain
By Jonathan Godon &
Eric Albuquerque
Science 8-4
Drugs of Addiction
• Drugs of addiction are drugs that induce a compulsive drug
craving, seeking and use even in the presence of extremely
negative effects
• Examples: Heroin, Alcohol, Marijuana, Cocaine, Nicotine
(Tobacco), PCP (phencyclidine or angle dust),
Methamphetamine, Ecstasy, LSD (Lysergic Acid
Diethylamide), Morphine (Opium)
Tobacco
Opium
Marijuana
Overall Areas of the Brain that are Affected by
Drugs of Addiction
Normal Brain vs. Drug Users’ Brain
Effects of Drugs of Addiction in the Reward
Areas of the Brain Affect the Function of Other
Areas
Hipp = Hippocampus
Thal = Thalamus
VP = Ventral Pallidum
Nacc = Nucleus Accumbens
VTA = Ventral Tegmental Area
( NAcc and VTA = Reward areas of the brain)
FC = Frontal Cortex
BLA = Amygdala
A Picture of a Normal Synapse
Normal synapse
•A normal synapse has a balance between the neurotransmitters in the synaptic cleft
•A synapse is the gap between the connection between the axon and dendrites of two
different neurons
•A neurotransmitter is a chemical that transports the electrical impulses sent by the
axon, across the synapse to the dendrite of the other neuron
•When an electrical impulse is sent from one neuron to the next, the neuron sending the
impulse will allow the vesicles holding the neurtransmitters in the axon to release the
neurtransmitters into the synaptic cleft
•Some molecules of the neurotransmitter will dock on receptors on the receiving
dendrite, and some will stay out in the synaptic clef. This will allow the impulse to be
sent to the next neuron
•When the neurotransmitters have done their job, they will be uptaken by the
presynaptic neuron or will by eaten up by an enzyme
A Picture of a Dopamine Synapse Affected by
Cocaine
Acting in Different Ways, Drugs of Addiction
Increase Dopamine Transmission in the Reward
Areas of the Brain
Alcohol and
opioids block
inhibition of VTA
dopamine neurons
by GABA
neurons
Dopamine released by
VTA neurons
stimulates the NCAA
neurons
Dopamine neuron in
the VTA are
stimulated directly
by nicotine
Cocaine and
amphetamines block
the dopamine
transporter and
increase dopamine
levels in the synapse
Normal Brain vs. Drug Users’ Brain
• In a normal brain, the dopamine levels are balanced and the cycle of the
neurotransmitters is not altered in anyway
• When you take a drug of addiction, for example cocaine, it causes a mass
accumulation of dopanime into the synapse. Cocaine blocks the uptake
channels, leaving the mass amount of dopamine out in the synaptic cleft to
attach, detach, and reattach to its receptors on the postsynaptic neurons in
the reward areas of the brain
• After the effect of the drugs wears off, and the dopamine is uptaken back
into the presynaptic neuron, the receptors shut down and to compensate for
the loss of receptors, you take the drug over and over again to keep the
dopamine levels up
How Drugs of Addiction Can Kill
• There are many ways in which drugs of addiction can kill
people through overdose
Stimulants such as cocaine and
methamphetamine trigger the
release of the adrenaline-like
hormone norepinephrine, which
causes: . Increased motor activity .
Increased heart rate . Increased
blood pressure . Narrowing of blood
vessels
1. Brain damage Increased
blood pressure increases the
risk of a ruptured blood vessel
in the brain. Narrowing of
blood vessels reduces blood
flow around the brain.
2. Heart attack Increased oxygen demand by
the heart (because of increased motor activity)
accompanied by reduced blood supply
(narrowing of blood vessels) can lead to heart
attack.
3. Overheating One function of dopamine is to regulate body
temperature. Altering dopamine levels with stimulants can affect the
body's ability to cool itself. Combined with increased motor activity, this
can lead to a dangerous increase in body temperature, resulting in organ
failure and death.
Sources
Bailey, Chris. “Neuronal Pathways Involved in Reward and Addiction.” pA2
Online 3.3 (2011): n. pag. Web. 19 Oct. 2011.
<http://www.pa2online.org/articles/article.jsp?article=43&issue=1&volume=2>
.
“Drugs Alter the Brains Reward Pathways.” Learning Genetics Genetic Science
Learning Center. U of Utah, 2011. Web. 20 Oct. 2011.
<http://learn.genetics.utah.edu/content/addiction/drugs/>.
Tafel, John A. “Addiction: Improve Your ‘Reward’ Circuits.” John A. Tafel, MD
Integrative Medicine and Physical Medicine and Rehabilitation. John A. Tafel,
n.d. Web. 19 Oct. 2011. <http://www.drjohntafel.com/>.
Tomkins, Denise M., and Edward M. Sellers. “Addiction and the Brain: The Role
of Neurotransmitters in the Cause and Treatment of Drug Dependence.” CMAJ
164.6 (2001): 817-821. Print.