Ch. 4 Module 2 Flashcards
What is the most common excitatory neurotransmitter in the CNS?
Glutamate
What is the most abundant inhibitory neurotransmitter in the CNS?
GABA
What are GABA A receptors?
They are inotropic and have chloride channels.
What are GABA B receptors?
They are metabotropic and they open potassium channels in the membrane.
What are the 2 subclasses of monamines:
indoleamines & catecholamines
catecholamines include
dopamine, norepinephrine
What are catecholamines broken down by?
COMT & MAO
Indoleamines include, and are broken down by what?
Serotonin, and is only broken MAO
What are the rule for determining if a substance is a neurotransmitter?
- Present in presynaptic vesicles
- Must occur naturally within system
- Must be released when an action potential invades the terminal.
- produce a PSP when applied
- Should have specific receptor in post synaptic membrane
- reception should lead to change in membrane potential of dendritic spine
- some specific mechanism should exist for inactivation of substance once released
- sam effect for stimulating nerve and releasing chemical on dendritic spine.
What are amino acid neurotransmitters?
simple molecules and do not need a synthesis pathway
What are the 2 amino acid neurotransmitters?
Glutamate & GABA
Glutamate
- is a very common chemical in the brain
- it is produced in the Krebs cycle
- all cells have glutamate
- it is excitatory
- crucial in the process of long term potentiation
What are the 3 types of iontropic glutamate receptors?
AMPA
NMDA
Kainate
AMPA
- responds strongly to the drug
- has a sodium channel
- generates an EPSP
Kainate
- has a sodium channel
- responds to a neurotoxin called kainic acid that is obtained from sea weed.
NMDA
- has a calcium channel
- is crucial in LTP
- NMDA receptor is blocked at RP by magnesium ion
Acetylcholine
- is found in skeletal muscle synapses
- is the most common excitatory neurotransmitter in the PNS
- heavily involved in Alzheimer’s disease
What are the two types of receptors for ACh?
Nicotine (PNS) & Muscarine (CNS)
Explain what the torpedo fish does?
- the torpedo fish generated electric shocks to stun prey and deter predators
What are monoamine neurotransmitters?
- are constructed from single amino acids and are broken down by monoamine oxidase
What is tyrosine?
is the precursor amino acid of catecholamines
what is tryptophan?
is the precursor amino acid of indoleamines
What is the breakdown enzyme that breaks down Tyrosine into DOPA?
Tyrosine Hydroxylase (TH)
What is the breakdown enzymes that breaks down DOPA into Dopamine?
Dopa Decarboxylase
What is Dopamine?
- has a dopaminergic synapse
- dopamine is inhibitory at most CNS synapses
- involved in Parkinson’s disease.
Are D1 dopamine receptors excitatory or inhibitory? and why?
are excitatory because they increase cAMP at the dendritic spine. Increasing cAMP means more sodium channels are open, depolarizing the membrane.
Are D2 dopamine receptors excitatory or inhibitory? and why?
are inhibitory because they decrease cAMP levels.
The pathway between the ventral tegmental area and the nucleus accumbens is what?
dopaminergic
What is the breakdown enzyme that breaks down dopamine to norepinephrine?
DBH
What is the breakdown enzyme for Serotonin?
MAO
Serotonin
Is the neurotransmitter that is released by the raphe nucleus
Where does is LSD obtained from?
From ergot - wheat or rye when it is damp and warm
What are the natural ligands in the brain?
Enkephalins
What are the 2 classes of endogenous opiate receptors that enkephalins activate?
Mu and Delta
Mu receptors
are the most general and are activated by endorphins and enkephalins but have the highest affinity for opiate drugs
Delta receptors
are only activated by enkephalins and opiate drugs.
What plays a major role in transmission of pain signals to the brain?
Substance P
What is the foundation molecule of ATP?
Adenosine
What does naloxone do?
It treats overdoses by knocking the opiate off the receptor
What does nitric oxide do?
- it is a messenger in many parts of the body
- one main function may be involved in long term potentiation
- functions as a retrograde messenger
Where are hormones released from?
secretory cells
What is the master endocrine gland in the body?
the pituitary gland
Explain how steroid hormones interact with the cell?
- enter cells and activate genes in the nucleus
- steroid hormones bond inside the cell
- water soluble hormones bind outside the cell
alpha receptors inhibit what?
adenylate cyclase to reduce second messenger levels
Beta Receptors activate what?
adenylate cycle to increase second messenger levels.
