Lecture 18: Drug Action and Synapse

agonists

drugs that increase the effectiveness of a given neurotransmitter

antagonist

drugs that decrease the effectiveness of a given neurotransmitter

What would a dopamine agonist do?

increase the activity of dopamine synapses

What does the botulin toxin do?

Prevents the release of acetylcholine by blocking the interaction between the synaptic vesicles and the cell membrane that leads to acetylcholine release and transmission of the impulse

How does the botulin toxin prevent the release of acetylcholine? What does this mean?

acts as an enzyme, a protease, that breaks down the protein complex that the vesicle binds to. This catalytic action means that it may take only one or two molecules to completely inactivate a nerve ending.

When animal toxins affecte acetylcholine, what happens to the body?

You either become paralyzed or have hyperactive movements in your muscles

How does botox work? Why is it not toxic?

A very dilute solution of botulin toxin is injected near specific facial muscles in order to paralyze them. Because so little is needed, this dose is not dangerous to the patient

What does nicotine do and how does that affect smokers?

Nicotine stimulates ACh receptors in skeletal muscle the same way ACh itself does causing Smokers to experience increased muscle tension and changes in sensitivity to muscle tension

What are some improvements in cognitive processes caused by nicotine?

reaction, speed, learning, recognition memory, short term episodic memory

What in your brain associates nicotine with environmental stimuli?

There are nAChR’s in the hippocampus that do this

What is the similarity between nicotine and curare?

both interact ACh receptors

Is nicotine an agonist or an antagonist? Why?

Nicotine is an agonist because it is similar to ACh that is stimulates the receptor in the same way (key in a key hole)

Is curare an agonist or an antagonist?

Antagonist because it just occupies that space. ACh can’t compete for the space and thus can’t stimulate muscles (tape over a key hole)

Why are sedatives not as popular as SSRI’s?

Because they are way easier to overdoes on

Benzodiazepines

anxiety meds that bind to GABA receptors and increase the frequency that they are open

Barbiturates

sedatives that increase the length of time GABA receptors are open as well as block AMPA receptors

Non-competitive medications

can work at the same time hence why it is super dangerous to consume alcohol while taking these drugs because it suppresses your system in multiple ways

competitive medications

only one can work at a time

What kind of receptors do opioids correspond with?

Are they excitatory or inhibitory?

* metabotropic
* inhibitory

What is an example of a narcotic agonist? How does it work?

Codeine is a narcotic agonist because it binds with the receptors

What is an example of a narcotic antagonist? How does it work?

narcan (Nalaxone) → it blocks the receptor instead of binding to it

What are the 4 types of stimulants?

* behavioral stimulants
* convulsants
* general stimulants
* psychoactive drugs

How do behavioral stimulants work?

Give to examples?

Effects?

block the dopamine transporters which take up DA from the synapse, thus agonists

* cocaine and amphetamine
* Euphoria, increased BP

how do convulsants work?

Example?

Attacks the nervous system by antagonizing glycine which results in permanent muscle contraction

* strychnine which is used as pest poison

How do general stimulants work?

Example?

increase cAMP activity, blocks adenosine receptors, reduces enzymes that break down cAMP

* caffeine

What are two major types of psychoactive/hallucinogenic drugs?

* LSD
* Marijuana

If we think glutamate could help with the effects of schizophrenia, why do we not use it as a treatment?

Because glutamate is everywhere and we don’t want to cause an increase in it in all parts of the body