neurotransmitters Flashcards
(15 cards)
What are the seven processes in neurotransmitter action?
- Synthesis & Storage
- Presynaptic Receptors
- NT Release
- Receptor Binding
- Signal Transduction
- Termination of Action
- Reuptake or Degradation
Each process plays a critical role in neurotransmitter function and communication in the nervous system.
What is an autoreceptor?
A receptor activated by neurotransmitter released by the neuron itself.
Autoreceptors help regulate neurotransmitter release and maintain homeostasis.
What is a heteroreceptor?
A receptor activated by neurotransmitter released by surrounding neurons.
Heteroreceptors facilitate communication between different neurons.
What is the effect of neurotransmitter release?
Primarily increases neurotransmitter release; sometimes decreases it.
The effect can vary based on the type of receptor and the context of neurotransmitter action.
What happens when an action potential arrives at the nerve terminal?
Opens voltage-gated Ca2+ channels, leading to synaptic vesicle fusion and neurotransmitter release.
This process is essential for neurotransmission and communication between neurons.
Name a drug that affects membrane potential by binding to sodium channels.
Local anesthetics.
They prevent action potentials by blocking sodium influx.
What is the mechanism of tetrodotoxin?
Blocks voltage-dependent sodium channels, preventing action potentials.
Tetrodotoxin is a potent neurotoxin found in certain marine animals.
What effect does batracotoxin have on neurons?
Opens voltage-dependent sodium channels, leading to excessive neuronal excitation.
Batracotoxin is derived from certain poison dart frogs.
What are the four receptor superfamilies?
- Ligand-gated ion channels
- G protein-coupled receptors
- Kinase-linked receptors
- Nuclear receptors
Each receptor type has distinct mechanisms of action and effects on cellular signaling.
What is the time scale for the effects of ligand-gated ion receptors?
Milliseconds.
These receptors mediate rapid synaptic transmission.
What is the role of reserpine in neurotransmitter action?
Inhibits vesicular storage of amine neurotransmitters.
Reserpine can lead to decreased levels of neurotransmitters like dopamine.
What is the precursor of dopamine?
L-dopa.
L-dopa is used in the treatment of Parkinson’s disease to increase dopamine levels.
What is the precursor of serotonin?
Tryptophan.
Tryptophan supplementation may be used to treat some forms of depression.
What are the methods for terminating neurotransmitter action?
- Non-synaptic release
- Reuptake by presynaptic neurons
- Degradation
- Internalization by postsynaptic neurons
These mechanisms ensure that neurotransmitter signaling is tightly regulated.
What is the unique mechanism of action of amphetamine?
- Inhibits VMAT
- Reversal of transporter
- Inhibition of degradation enzyme
Amphetamines increase the levels of dopamine and norepinephrine in the synaptic cleft.
