Nervous System 6

Question 1

What does metabotropic mean

Answer 1

Means that the receptor recognizes something that will result in a change in the internal biochemistry of the cell, changes whats going on inside

Question 2

Types of receptors in excitatory synapses

Answer 2

Ionotropic: AMPA and NMDA, allow the passage of ions
Metabotropic: metabotropic glutamate receptors, involved in changing biochemical processes inside the cell
All bind glutamate

Question 3

Synonyms of metabotropic receptors

Answer 3

G-protein coupled receptors, GPCRs

Question 4

What effect does glutamate have on mGluR’s

Answer 4

It induces them to change their shape/conformation (technically does that for all), activates it
Causes that transmission of a signal, from outside to inside, and this signal will cause a sequence of proteins being activated (a cascade), ultimately resulting in the generation of small molecules inside the cell (like neurotransmitters but inside) called second messengers,
Note: these receptors amplify the response meaning even just one being activated produces a lot of 2nd messenger molecules

Question 5

What is the first protein to be activated IN the cell after a metabotropic receptor has bound to glutamate

Answer 5

G protein

Question 6

What’s an mGluR

Answer 6

Metabotropic glutamate receptor

Question 7

How are second messengers like neurotransmitters

Answer 7

Once produced, will start diffusing throughout the cell and activate processes within the cell
Same way a neurotransmitter would diffuse throughout the synaptic cleft

Question 8

What can the second messengers do

Answer 8

They can activate/open ion channels by the molecule binding from the inside, bind to proteins to activate them (trigger them to function), bind to proteins that enter the nucleus and affect the transcription of genes,

Question 9

How can protein kinases be activated

Answer 9

By second messengers
Activated to go phosphorylating things, phosphorylation can also activate other proteins and their processes

Question 10

Are responses from metabotropic receptors quick or long and why

Answer 10

Long because they involve creation of the 2nd messengers, diffusion of the second messenger, it’ll activate stuff like protein kinases that will go activate other enzymes that’ll go do something else etc
Takes a minute but effects are usually longer-lived than say the opening of AMPA receptors that open fast but dont last

Question 11

Receptors in inhibitory synapses

Answer 11

GABA A receptors and metabotropic GABA receptors called GABA B

Question 12

Neuromodulators

Answer 12

Name referring to neurotransmitters than only bind to metabotropic receptors and not ionotropic receptors (like glutamate that binds to both)
Not called a neurotransmitter since that refers more to the fast transmission of APs whereas these are more about the slow-burn biochemistry of the cell
Ex: dopamine, serotonin, norepinephrine, neuropeptides (such as endorphins) all act primarily or entirely on metabotropic receptors, slow changes

Question 13

Norepinephrine neurons

Answer 13

Most neurons respond to norepinephrine, has a pull on sleep/wake cycles (not the only factor), involved in attention (when something in the external environment catches your attention like a fire alarm)
Increase in norepinephrine is used to help with attention in ADHD
Neuromodulator

Question 14

Serotonin

Answer 14

Neuromodulator
Most cells respond to serotonin, seems to be involved in mood (like depression)
SSRIs are used to keep up serotonin levels in depressed patients

Question 15

Dopamine

Answer 15

Neuromodulator
Related to learning, involved in the connection between something happening and getting rewarded for it
Most addictive drugs are addictive due to their effects of increasing dopamine, like cocaine or nicotine
Note: connection as in you start to associate the environment or thing (like a box of cigarettes) to the dopamine high and good feeling so when you see that cue you crave it, basis of addiction

Question 16

Endorphins

Answer 16

Endogenous substances that act like morphine (rather morphine acts like it), so all opioids have this effect: morphine, codeine, heroin, all act the same way: by activating a metabotropic receptor in the brain normally activated by endorphins
Endorphins suppress pain and are associated with pleasure

Question 17

Neurons that release neuromodulators, where do they originate

Answer 17

In the small brainstem or midbrain nuclei, and their axons branch A LOT in the brain, which is why they’re capable of reaching most neurons

Question 18

Drugs that target the Neuromodulator systems

Answer 18

Prozac for depression: affects serotonergic transmission
Amphetamines, cocaine and other stimulants: affect dopamine and norepinephrine transmission