Neurotransmitters Flashcards
What are the 2 broad families of neurotransmitter receptors?
- Inotropic receptors
- Metabotropic receptors
What are inotropic receptors also referred to as?
Ligand-Gated Ion Channels
Inotropic receptors are activated by a _______ and ________ opens a channel.
- ligand
- directly
What is a ligand?
A term for any substance that can bind to a target protein.
What are metabotropic receptors alse referred to as?
G-Coupled Receptors
Neurotransmitters also bind to metabotropic receptors, but instead of immediately opening an ion channel, the next step is to activate an intermediate protein known as ___________. This intermediate protein can then influence the opening of ion channels, but it can also initiate signaling cascades within the cell via __________ messengers.
- G-protein
- secondary
G protein receptors have a ______ action but have __________ effects.
- slower
- widespread
Metabotropic receptors ________ activate ion channels.
indirectly
GLUTAMATE
GLUTAMATE
What is the most abundant neurotransmitter in our brain and CNS? It is also involved in virtually every excitatory brain function.
Glutamate
What are the 2 functions glutamate has?
- learning and memory
- synaptic plasticity
What are the 3 glutamatergic inotropic receptors?
- NMDA
- AMPA
- Kainate
In addition to NMDA and AMPA, glutamate can bind to the inotropic receptor __________ receptors.
Kainate
Kainate receptors have both ________ and __________ actions.
-pre and postsynaptic
- presynaptic: GABA
- postsynaptic: Glutamate
Unlike NMDA/AMPA receptors, kainate receptors play only a minor role in ______________.
synaptic plasticity
What are the 2 functions of glutamatergic metabotropic receptors?
- modulates glutamate release
- affect postsynaptic excitability
Ligands and other NT (such as drugs) can also bind to receptors. If they have the same effect as the NT, they are known as __________. If they block the effects of the NT, they are known as _________.
- agonist
- antagonist
Some drugs can bind to the site the neurotransmitter binds to and have the exact opposite effect, what are these drugs called?
inverse agonists
Drugs may bind to a site on the receptor that is seperate from the site where the NT binds and affect the likelihood that the NT will bind. What are these called?
neuromodulators
PCP inhibits the reuptake of dopamine, norepinephrine, and serotonin and also inhibits the action of glutamate by doing what?
blocking NMDA receptors
It is thought that the drug Riluzole blocks the release of _________ from nerve cells, helping to treat ALS.
glutamate
How does glutamate excitotoxicity work?
- increased glutamate
- continuous AMPA/NMDA binding, leaving channels open too long
- way too much Ca+ ends up in cell
- apoptosis occurs (cascade of cell death)
What are 3 diseases involved with the activity of glutamate?
- Schizophrenia
- Epilepsy
- Alzheimer’s
_________ glutamate leads to ___________ of NMDA receptors, which is thought to be a cause of epileptic seizures.
- excessive
- overactivity
Glutamate ___________ are potential anticonvulsants.
antagonists
GABA
GABA
What is the major inhibitory MT in the CNS, particularly at interneurons within the spinal cord?
GABA
What are the functions of GABA?
- treatment of anxiety, rehab for drug abuse
- inhibits motor, sensory, and cognitive neurons: sedation, muscular/cardiorespiratory relaxation, pain inhibition
What is the inotropic GABA receptor?
GABAᴀ
What is the metabotropic GABA receptor?
GABAʙ
What are 4 GABA agonists?
- alcohol
- benzodiazepines
- barbiturates
- baclofen
Alcohol can happen on both the _______ and _____________.
pre and postsynaptic neuron
Benzodiazepines is a class of psychoactive drugs used to treat a range of conditions, including _______ and _________. It ________ post synaptic receptors sensitivity to _______ binding.
- anxiety and insomnia
- increases
Barbiturates are for the treatment of anxiety, insomnia, seizure disorders, and muscle relaxants but were used less when ___________ was created. They acted to ___________ the openings of individual GABA channels.
- benzodiazepines
- prolong
Baclofen is an ____________ drug and _______________ the presynaptic release of GABA in the spinal cord, leading to relaxation.
- antispasticity
- increases
What are 2 diseases GABA is used to treat?
- Epilepsy
- Huntington’s Diseases
GLYCINE
GLYCINE
Glycine is found in the __________ and ________________. It has an ___________ post-synaptic response.
- brain stem and spinal cord
- inhibitory
What is the function of glycine?
- inhibits spinal interneurons
- functions alongside GABA
Glycine only has _________ receptors.
inotropic
When glycinne receptors are activated, _______ enters the neuron via inotropic receptors.
chloride
What is a potent glycine antagonist that is used primarily as a pesticide?
strychnine
What 2 conditions are glycine used in?
- Spasticity
- Spinal Shock (have too much glycine)
What is spinal shock?
- acute phenomenon seen after spinal cord injury
- patient presents with LMN symptoms, despite UMN injury, that lasts hours-1 week after injury
- significant elevated glycine levels found after injury, thought to be a strong component to why spinal shock occurs
ACETYLCHOLINE
ACETYLCHOLINE
ACh is widely distributed through what structures?
- motor neurons, basal ganglia, ANS
- NMJ
ACh has an ___________ post-synaptic response
excitatory
ACh is the major conveyer of information in the _______. All _______ neurons use ACh to elicit fast-acting effects on muscle membranes
- PNS
- motor
What are the functions of ACh?
- triggers muscle contraction
- ANS involvement (slow HR, constrict pupils, increase digestive secretions and smooth muscle contractions)
- stimulate excretion of certain hormones
- In CNS involved in wakefulness, attentiveness, anger, sexuality
