Chapter 8 Drugs And Hormones Flashcards
Psychopharmacology
The study of how drugs affect the nervous system and behaviour.
Drugs
Chemical compounds administered to bring desired change in the body
Psychoactive drugs
Substances that act to alter mood, thought, or behaviour and are used to manage neuropsychological illness
Route of administration
The way in which a drug enters and passes through the body to reach its target
Which is the most complex route for a drug to reach its target?
Oral administration
Weak acids in the stomach
Are readily absorbed
Weak base in the stomach
Must pass through the stomach & into the intestine
What properties must a drug have in order to travel through the bloodstream
-Must be hydrophilic -It’s molecules must be small enough to pass through the pores of capillaries (vessels that carry blood to cells)
How much of a drug is reduced if each obstacle to the brain is eliminated
The amount of the drug needed is reduced by a factor of 10
Blood brain barrier (BBB)
Made of capillaries that have tight junctions formed by endothelial cells. Prevents drugs from entering the brain easily.
The three brain regions that lack a blood-brain barrier
Pineal gland, pituitary gland, and the area postrema
Lack of BBB in pituitary gland
Allows secretion of hormones into blood system. Allows other hormones to enter the pituitary (this causes the pituitary to secret hormones)
Lack of BBB in the area postrema
Allows toxic substances in the blood to trigger vomiting
Lack of BBB in pineal gland
Enables hormones to reach it and modulate the day-night cycles
2 ways vital substances (oxygen, CO2, waste) cross the BBB
1) Small molecules(CO2, O) are not ionized = fat soluble. Therefore, they can pass through the endothelial membrane 2) molecules of food components (glucose, amino acids) are transported by specialized proteins (pumps, active transport systems)
How does the body eliminate drugs
Through dilution and catabolic process
Catabolic process
The breakdown of chemical compounds
The seven major steps in neurotransmission that a drug can affect in a synapse. Pg 242
1) synthesis 2) storage 3) release 4) receptor interaction 5) inactivation 6) reuptake 7) degradation
2 ways a drug can influence synaptic function
1) agonists 2) antagonists
Agonists
Drugs that increase the effectiveness of neurotransmission. Ex. Black widow spider venom promotes excess release of acetylcholine (ACh) = paralysis
Antagonists
Drugs that decrease the effectiveness of neurotransmission. Ex. Botulin toxin blocks release of ACh = paralysis. Used to stop spasms.
Organophosphates
Class of compounds that bind irreversibly to acetylcholinesterase. Are extremely toxic.
Tolerance
A decrease response to a drug over time. Develops with repeated used
3 types of tolerance
1) metabolic tolerance 2) cellular tolerance 3) learned tolerance
Metabolic tolerance
Increase in enzymes needed to breakdown (ex.) alcohol. Therefore, alcohol is metabolized quicker and blood alcohol levels are reduced
Cellular tolerance
Activities of brain cells adjust to minimize the effects of ex. Alcohol present in the blood. May explain why people don’t appear drunk even though they have high blood-alcohol levels
Learned tolerance
People learn to cope with daily demands of living while under the influence of alcohol.
Sensitization
Increased responsiveness to a drug. Develops with occasional use (not used repeatedly)
Classification of psychoactive drugs is based on…
The most pronounced behavioural or psychoactive effect produced by a drug
Seven class of psychoactive drug classifications
1) antianxiety agents and sedative hypnotics 2) antipsychotic agents 3) antidepressants 4) mood stabilizers 5) opioid analgesics 6) psychomotor stimulants 7) psychedelic and hallucinogenic stimulants
Antianxiety agents
Drugs that reduce anxiety; minor tranquilizers such as benzodiazepines and sedative-hypnotic agents. Valium is widely prescribed. Can produce cross tolerance. Harder to overdose
Sedative Hypnotics
Drugs that reduce anxiety; alcohol and barbiturates. Can produce a tolerance after repeated use. Easy overdose
Benzodiazepines
Used for coping with major life streamers like a traumatic accident or death. Also a presurgical relaxation agent
Barbiturates
A drug mainly used for anesthesia. Can induce sleep, anesthesia, & comas
Cross tolerance
When the tolerance developed for one drug is carried over to a different member of the drug group
Main target for antianxiety and sedative-hypnotic drugs
Receptor sites for GABA (major inhibitory neurotransmitter)
The 3 binding sites of GABA(a)
1) sedative-hypnotic site 2) GABA site 3) antianxiety site Each site is located on the GABA receptor.
Fetal alcohol syndrome (FAS)
Pattern of physical malformation and mental retardation
Dissociative anaesthetics
Group of sedative hypnotics developed as anesthetic agents; produce altered states of consciousness and hallucinations and impairs memory for recent events; “date-rape” drug
Psychosis
Neuropsychological conditions characterized by hallucinations or delusions. Ex. Schizophrenia
Major tranquilizers (neuroleptic)
Antipsychotic drugs that blocks the D2 (dopamine) receptor; mainly used on schizophrenics
Dopamine hypothesis of schizophrenia (pg 251)
Schizophrenia symptoms are due to excess activity of the neurotransmitter dopamine
Amphetamines
Increase dopamine activity; cause schizophrenia like symptoms. Also blocks the reuptake of dopamine (dopamine can’t get reabsorbed by the synaptic cleft)
Chlorpromazine (pg 252)
Antagonist; occupies the dopamine site on the D2 receptor = prevents receptor activation