Psychopharmacology Flashcards
Routes of drug administration
-oral is safest easiest and most common, but also most complex as there are more barriers the drug has to cross to have its desired effect
-inhalation or injection produce much faster effects because less barriers
Drug routes into the nervous system
Barrier free brain sites
-pineal gland: allows entry of chemicals that affect day-night cycles
-pituitary: allows entry of chemicals that influence pituitary hormones
-area postrema: allows entry of toxic substances that induce vomiting
Drug action at synapses
-most psychoactive drugs exert their effects by influencing chemical reactions at synapses
-agonist: substance that enhances the function of synapse
-antagonist: substance that blocks the function of a synapse
Drugs can alter chemical processes at any of seven major stages of synaptic transmission
- Synthesis
- Storage
- Release
- Receptor interaction
- Inactivation
- Reuptake
- Degradation
Antianxiety agents and sedative hypnotics
-Benzodiazepines: minor tranquilizers, antianxiety agents-> drugs that reduce anxiety (Valium, Xanax), often used for temporary purposes (coping with stress from life event)
-Alcohol
-GABA agonists
GABA receptor
Excitation produces an influx of chloride ions which stabilizes the neuron
-has 3 sites: sedative-hypnotic site- alcohol, directly influences Cl influx ; anyianxiety site: benzodiazepines- enhances binding effects of GABA, effect is dependent upon amount of GABA present - harder to overdose
Antipsychotic agents
• Major Tranquilizer (Neuroleptic)
- Drug that blocks the Dz dopamine receptor
- Used mainly for treating schizophrenia
- Mechanism of therapeutic action is still not understood
• Immediate effect of reducing motor activity
• After short period of use, there is a reduction in the symptoms of schizophrenia
• Negative side effect: Dyskinesia (impaired control of movement)
3 classes of antidepressants
- Monoamine Oxidase (MAO) Inhibitors -Block MAO from degrading neurotransmitters such as DA, NA, and 5-HT
- Tricyclic Antidepressants
- First-generation antidepressants - block 5-HT reuptake transporter proteins - Second-Generation Antidepressants
- Similar to 2. but more selective in its action on the serotonin reuptake transporter proteins e.g. sertraline (Zoloft), fluoxetine (Prozac)
• Selective Serotonin Reuptake Inhibitors (SSRis)
Narcotic analgesics
• Endorphin
- Peptide hormone that acts as a neurotransmitter and may be associated with feelings of pain or pleasure
- Mimicked by opiate drugs such as morphine, heroin, opium, and codeine
• Morphine acts on three opioid-receptor classes
- Mu, delta, and kappa
- Mu receptor is critical for morphine’s effect on pain and for its addictive properties
Stimulants
Behavioural Stimulants
• Increase motor behaviour and elevate a person’s mood and level of alertness
• Cocaine
- Blocks dopamine reuptake
• Amphetamine
- Dopamine agonist: releases dopamine into the synapse and blocks the reuptake of dopamine, as well
Addiction and dependence
• Psychomotor Activation
- Increased behavioural and cognitive activity
- At certain levels of consumption, the drug user feels energetic and in control
- Occurs with many drugs
• Is there a common target (such as dopamine neurons) for abused drugs?
Tolerance
-Lessening of response to a drug overtime
-Larger dose is required to maintain the drug’s initial effect
Disinhibition theory
• Alcohol has a selective depressant effect on the cortex (the region of the brain that controls judgment), while sparing subcortical structures (those areas of the brain responsible for more-primitive instincts, such as desire)
• Limitation:
- behaviour under the influence of alcohol often differs depending upon the context
