Download Document

Psychoactive drugs
By Martin Samaj NO i copied from
the book
What are psychoactive
drugs
• Drugs that act upon the central
nervous system (CNS)
• Are able to cross the blood
brain barrier
• Because of their action upon
CNS they are able to alter:
perception, cognition, mood,
consciousness and behavior
• They have many uses ranging
from recreational to
therapeutic
Excitatory and Inhibitory substances
• Most psychoactive drugs Excitatory - Nicotine,
alter the brain's function by cocaine and
amphetamines
disrupting synaptic
transmission
• Excitatory drugs either
promote transmission at
excitatory synapses or
Inhibitory - benzodiazepines,
inhibit transmission at
alcohol, THC
inhibitory synapses
• Inhibitory drugs do the
opposite
Addiction
Almost all of psychoactive drugs are addictive to some extent.
Addiction can cause both physical and social damage.Three
factors increase the potential of an individual to become
addicted:
• Dopamine secretion - A feature of many addictive
psychoactive drugs is that transmission is stimulated at
synapses using dopamine as neurotransmitter
• Genetic predisposition - Even if the drug itself is addictive
the rate at which one becomes addicted greatly depends on
genetics. Addiction is more common in some families than in
others which may indicate that genes can play a role in
addiction
• Social factors - Peer pressure, poverty and social
deprivation can prevent or encourage the like hood for
addiction
Cocaine
• Is an excitatory psychoactive drug that
stimulates dopamine synapses in the brain
• Cocaine binds to membrane proteins that
pump dopamine back into the presynaptic
neuron
• It blocks these transporters causing
dopamine levels to build up in the synapses
• Dopaminergic synapses are responsible for
pleasurable feelingstransmission at the
synapses
• Cocaine is highly addictive and widely
abused
• Crack is a form of cocaine that forms vapor
when heated
• When inhaled it has a very rapid onset and
intense effects.
THC (tetrahydrocannabinol)
• Cannabis contains a variety of active
substances, one of them being THC
which causes the most psychoactive
effects
• THC binds to specific receptors in the
brain, at cannabinoid receptors
• When THC binds to its receptor, it blocks
the release of excitatory
neurotransmitters, thus making it an
inhibitory drug
• Cannabinoid receptors are found in many
parts of the brain including cerebellum,
hippocampus and cerebral hemispheres
• Some of the acute effects are: short term
memory loss, stimulation of appetite,
euphoria, sleepiness, anxiety, confusion
Thank you for your attention