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Most people will take a pill,
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receive an injection,
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or otherwise take some kind of medicine
during their lives,
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but most of us don't know anything
about how these substances actually work.
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How can various compounds impact the way
we physically feel,
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think,
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and even behave?
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For the most part, this depends on
how a drug alters the communiation
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between cells in the brain.
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There are a number of different ways
that can happen.
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But before it gets into the brain,
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any drug must first reach the blood stream
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on a journey that can take anywhere
from seconds to hours,
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depending on factors like how
it's administered.
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The slowest method is to take
a drug orally
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because it must be absorbed by
our digestive system
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before it takes effect.
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Inhaling a drug gets it into
the blood stream faster.
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And injecting a drug intravenously
works quickest
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because it pumps the chemicals directly
into the blood.
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Once there, the drug quickly reaches
the gates of its destination, the brain.
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Th entrance to this organ is guarded
by the blood-brain barrier,
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which separates blood
from the nervous system
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to keep potentially dangerous
substances out.
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So all drugs must have a specific
chemical composition
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which gives them the key to unlock
this barrier and pass through.
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Once inside, drugs start to interfere
with the brain's normal functioning
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by targeting its web of neurons
and synapses.
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Neurons are brain cells that have
a nucleus, dendrites, and an axon.
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Synapses are structures placed along
the dendrites or the axon
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which allow the exchange of
electrochemical signals between neurons.
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Those signals take the form of chemicals
called neurotransmitters.
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Each neurotransmitter plays different
roles in regulating our behaviors,
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emotions,
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and cognition.
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But they all work in one of two ways.
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They can either inhibit
the receiving neuron,
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limiting its activity,
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or excite it,
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creating a new electrochemical signal
that spreads throughout the network.
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Any leftover neurotransmitter usually
gets degraded
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or reabsorbed
into the transmitting neuron.
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A drug's effectiveness stems
from its ability
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to manipulate these synaptic transmissions
at different phases of the process.
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That results in an increase or a decrease
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in the amount of neurotransmitters
being spread.
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For instance, common antidepressants,
like SSRIs,
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stop the reabsorption of serotonin,
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a neurotransmitter that modulates
our moods.
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This effectively pushes more of it
into the neural network.
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Meanwhile, painkillers, like morphine,
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raise levels of serotonin
and noradrenaline,
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which regulate energy,
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arousal,
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alertness,
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and pleasure.
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Those same neurotransmitters also
effect endorphin receptors,
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reducing pain perception.
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And tranquilizers works by increasing
the production of GABA
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to inhibit neural activity
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putting the person in a relaxed
or sedated state.
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What about illegal or elicit drugs?
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These have powerful impacts on the brain
that we're still trying to understand.
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Crystal meth, an amphetamine,
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induces a long-lasting release
of dopamine,
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a neurotransmitter linked with
the preception of reward and pleasure.
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It also activates noradrenaline receptors,
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which increases the heart rate,
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dilates pupils,
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and triggers the body's fight
or flight response.
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Cocaine blocks the reuptake of dopamine
and serotonin,
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pushing more into the network
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where they boost energy,
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create feelings of euphoria,
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and suppress appetites.
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And hallucinogenic drugs have some
of the most puzzling effects.
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Substances like LSD,
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mescaline,
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and DMT
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all block the release of serotonin,
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which regulates mood and impulsivity.
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They also have an impact
on the neural circuits
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involved in perception, learning,
and behavioral regulation,
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which may explain why these drugs
have such powerful impacts.
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Even if some of these
effects sound exciting,
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there are reasons why some of these drugs
are highly controlled and often illegal.
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Drugs have the power to alter
the brain's chemistry,
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and repeated use can permanently
rewire the neural networks
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that support our ability to think,
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make decisions,
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learn,
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and remember things.
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There's a lot we still don't know
about drugs and their effects,
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but the good and the bad.
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But those we do know about are the ones
we've studied closely,
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and turned into effective medicines.
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As our knowledge grows about drugs
and the brain,
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the possibilities will also increase
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for treating the many medical problems
that puzzle researchers today.
Ростислав Голод
You've got a misspell in 3:03. Should be ''illicit'' NOT ''elicit"!