Transcript 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