Lecture 4 Flashcards
What is a neurotransmitter?
A chemical released by the presynaptic terminal button in response to an action potential
-briefly binds to a specialized protein called a receptor that is located on the postsynaptic membrane
-like a key fitting a lock
What is the criteria for a neurotransmitter?
-its synthesis is within a neuron
-it is released in response to a neuronal depolarization
-it binds to a postsynaptic receptor
What are some examples of a neurotransmitter?
-acetylcholine
-dopamine
-norepinephrine
-epinephrine
-serotonin
-glutamate
-GABA
-endocannibinoid
-endogenous opioid
What is a ionotropic receptor?
-type of receptor that, when stimulated, immediately opens an ion channel
- is associated with a ligand-activated ion channel
What is a metabotropic receptor?
-type of receptor that, when stimulated, does not immediately open an ion channel
-associated with signal proteins and G proteins
What is reuptake?
-the drawing back, in the the presynaptic button, neurotransmitter molecules after their release into the synapse
-the more common of the two mechanisms for deactivating released neurotransmitters
What is enzymatic degredation?
-the breakdown of neurotransmitters by enzymes
-the less common of the two mechanisms for deactivating released neurotransmitters
What is glutamate?
-the most prevalent excitatory neurotransmitter in the brain
-one of the amino acid neurotransmitters that is common in the proteins we consume
-overstimulation by this neurotransmitter can be toxic, causing cell death
What is GABA?
-most prevalent inhibitory neurotransmitter int he brain
-synthesized by a simple modification of the structure of glutamate
-alcohol acts primarily as an agonist of in the brain so that at moderate doses it causes cognitive, perceptual, verbal, and motor impairments- even though at low doses it can facilitate social interaction
-an excessive decrease in this can result in convulsions and possibly death
-agonists of this are used to treat seizures and other disorders like anxiety and insomnia
What is dopamine?
-neurotransmitter that naturally converts into norepinephrine
-has been implicated in the pathology of both parkinsons disease and schizophrenia
-plays an important role in the control of motor movement and in motivational aspects of drug use
What is norepinephrine?
-neurotransmitter that naturally converts directly into epinephrine
-also known as noradrenaline
-dysfunction of this neurotransmitter system is associated with attention deficit disorder
-plays an important role in maintaining vigilance and arousal
What is epinephrine?
-neurotransmitter that is naturally converted directly from norepinephrine
-also known as adrenaline
-used by the autonomic nervous system to produce a series of changes in the body called the ‘fight-or-flight response”, such as increased heart rate
What is serotonin?
-neurotransmitter is also known a 5-hydroxytryptamine, or 5-HT
-plays an important role in the sleep-wake cycle and mood
-antidepressants (like tricyclics and SSRIs) act primarily as agonists of in the brain to produce antidepressant effects
What is acetylcholine?
-neurotransmitter released from cholingeric neurons
-stimulates muscles when naturally released at neuromuscular junctions
-binds to nocotonic and muscarinic receptors
-plays an important role in REM slee, cortical activation, and learning/memory
-dysfunction of this system can = alzheimers disease
-tobacco acts primarily as an agonist of it in the brain to make people feel more alert and less hungry
-used by autonomic nervous system to produce a series of changes in the body that could be called the ‘rest and digest response’, such as decreased heart rate
What is an endocannabinoid
-neurotransmitter that is similar to the main psychoactive ingredient of marijuana
-tends to have most of its effects on presynaptic neurons, inhibiting subsequent synaptic transmission
- activation causes sedation, stimulates appetite, + impairs concentration and memory
-agonists of this, at social doses, produce a sense of well-being, hilarity, carefree relaxation, altered perception, increased hunger, and subtle changes in thought
-agonists of this neurotransmitter, while producing pleasurable effects, have a low addiction potential and rarely produce obvious withdrawal symptoms
