33.4 Effects of Drugs
Effects of DrugsSection 33.4
How Drugs Work· drug - a substance, natural or artificial, that alters the function of the body
ex. antibiotics, over-the-counter (OTC) pain relievers, cocaine, marijuana, caffeine
· drugs that affect the nervous system...1. increase amount of neurotransmitter
released into synapse2. prevent neurotransmitters from binding to a
dendrite by blocking receptor site3. prevent a neurotransmitter from leaving a
synapse4. imitate a neurotransmitter
Dopamine· a neurotransmitter· involved with control of body movements and other functions, and with feelings of pleasure and reward
"feel good" hormone· excess dopamine is reabsorbed by the neuron that released it· many drugs that affect the NS influence the level of dopamine
Stimulants· drugs that increase alertness and physical activity· nicotine
increases amount of dopamine released into synapse
constricts blood vessel, raises blood pressure, makes heart work harder
linked to lung cancer· caffeine - most commonly used
binds to adenosine receptors on neurons in brain
- adenosine slows down brain making you drowsy
caffeine blocks adenosine and gives you a burst of energy
temporarily raises epinephrine (adrenaline) levels
Depressants· drugs that slow down NS, lower blood pressure, interrupt breathing, slow heart rate, relieve anxiety, make you sleepy· alcohol
affects at least 4 neurotransmittersshort-term effects - impairs judgement, coordination,
reaction timelong-term effects - reduction in brain mass, liver damage,
stomach and intestinal ulcers, high blood pressure· inhalants - chemical fumes
short-term effects - intoxication, nausea, vomiting, deathlong-term effects - memory loss, hearing loss, vision
problems, nerve damage, brain damage
Tolerance & Addiction· tolerance can lead to addiction· tolerance - need more of the same drug to get the same effect· addiction - physiological (body needs it) or psychological (you think you need it) dependence on a drug
physiological - increased levels of dopamine in synapse (feelings of pleasure)
quitting decreases dopamine levels (pleasing feeling leaves)
psychological - use the drug for emotional reasons