Lecture 15 Flashcards
What is psychopharmacology?
The study of how drugs affect the nervous system and behaviour
What are psychoactive drugs?
Substances that act to alter mood, thought, behaviour (sugar, caffeine, alcohol)
What treatment proved to work well on the frozen addicts?
L-Dopa and Stem Cells extracted from human fetal brains
Why doesn’t stem cell implants work well with Parkinsons?
As Parkinson’s is continuous cell loss versus simply lesioning
What are psychoactive drugs typically used for?
Management of neurophysical illnesses, recreational use, potential for abuse.
What are some routes of administration for drugs?
Injection, inhalation, orally
What are the advantages of oral administration?
Safe, easy, and convenient
What are the advantages of inhalation?
Quick, less barriers than oral administration (en route to the brain)
What are the advantages of injection?
Quick acting, few barriers
What are some of the disadvantages of oral administration?
Number of barriers that the drug must pass through (stomach/intestinal lining, blood stream), slow acting
What are some of the disadvantages of inhalation?
Damage to lung tissue as a result of exposure.
What are some of the disadvantages of injection?
Drugs must be hydrophillic, harder to reverse any negative effects.
How do we get substances past the blood-brain barrier?
Have to be small and water-soluble- or go through the areas of the brain not protected by the BBB (pineal gland, pit gland, area postrema).
What are some of the mechanisms that catabolize drugs?
Liver** (9/10 times) (cytocrome P450 enzymes), kidneys, intestines.
What are some of the ways that excretion may occur?
Urine** (9/10 times), feces, sweat, exhalation, breast milk
What is a problem that is happening with Fluoxetine excretion?
Because it is excreted via urine, it ends up in our waterways, and sewage plants are unable to process it. It is now present in high enough levels to alter the behaviours of local fish species (fathead minnows specifically).
What is the species typical behaviour of the fathead minnow and how does fluoxetine alter this?
Species typical- Males: build nest AND take care of eggs, females visit nest and lay eggs
Fluoxetine fish- males will attack the females
What process does drug action mimic in the neurons?
Neurotransmitters! Synthesis, storage, release, interaction, inactivation, reuptake, degradation
What are the 2 effects that drugs can have on the synapse?
Agonists- Enhance functions of the synapse
Antagonists- Block function of the synapse.
What are some things that agonists can do?
Increase certain neurotransmitters, promote release of neurotransmitters, stimulate receptors, block inactivation
What are some things that antagonists can do?
Block release and receptors.
What is tolerance?
A decrease in a response to a drug with the passage of time
What was the study done in the 50s on alcohol tolerance?
Gave people alcohol everyday for 13 weeks-population was convicts BECAUSE they should have a BAC of 0. Results: After 15-20 days, BAC levels fell and so did signs of intoxication.
What is metabolic tolerance?
The number of enzymes that breakdown alcohol increases.
What is cellular tolerance?
Neurons adjust to minimize effects
What is learned tolerance?
Learning to cope with daily living under the influence
What is sensitization?
Increased responsiveness to successive, equal doses of a drug. Likely to occur as a result of intermittent use of a drug.
How did Robinson and Becker study sensitization?
Injected rats with amphetamine every 3-4 days. Found that stimulus novelty and intermittent use in part drives the sensitization response.
What are some of the changes that occur at the synapse with drug sensitization?
Increase in the amount of neurotransmitter released, increase in number of receptors present on the post-synaptic membrane, decrease in the rate of transmitter metabolism/reuptake, changes in the number of synapses.
What is an example of an adenosinergic drug and what do they do?
Caffeine- most widely used psychoactive substance in the world (80% of US population). Adenosine receptor antagonist (adenosine induces drowsiness). Increase in cAMP=more glucose. Release of dopamine and acetylcholine.
What is an example of a cholinergic drug and what do they do?
Nicotine-Activates acetylcholine nicotinic receptors (agonist). Found in tobacco plant, but also potatoes, tomatoes, and eggplants
Acetylcholine psychadelics-block or facilitate transmission at ACh synapse (like atropine, which is an agonist) makes you feel like you’re flying, associated with witches.
What is an example of a GABAergic drug and what do they do?
Benzodiazepines: Diazepam (Valium), Alprazolam (Xanax), Alcohol, sedatives etc. Ramps up inhibition in the body. Alcohol maximizes pore openings, allowing GABA to bind, benzos influence the frequency of the pore opening
What is cross-tolerance?
Reduction of response to a novel drug because of tolerance of chemically related drug.
