Synapses and Synaptic Transmission Flashcards
What membranes deliver info in the form of neurotransmitters?
presynaptic membranes
What membranes receive info because they have receptors for neurotransmitters?
postsynaptic membranes
What causes the release of neurotransmitters into the synaptic cleft?
action potential
What is the type of transmission where the release of a chemical at a synapse whereby one cell influences another?
chemical synaptic transmission
What are ion-opening channels called?
ligand-gated channels
What types of synapses generate POSTsynaptic potentials?
neuromuscular, axosomatic, axodendritic
What type of synapses generate PREsynaptic inhibition/facilitation?
axoaxonic
What are potentials caused by changes in ion concentration across the postsynaptic membrane?
postsynaptic potential (PSP)
What causes EPSPs (excitatory)?
local depolarization
What causes IPSPs (inhibitory)?
local hyperpolarization
How do EPSPs work?
nt binds to postsynaptic receptors causing an opening of Na+ or Ca2+ channels
Summation of what type of PSPS will lead to an action potential?
EPSPs
How do IPSPs work?
nt binds to postsynaptic receptors causing an opening of Cl- or K+ channels
What occurs when NTs causing depolarization will lead to an increased release of NTs?
presynaptic facilitation
What occurs when NTs causing hyperpolarizing will lead to a decreased release of NTs?
presynaptic inhibition
What are the three mechanisms that remove NTs from the synaptic clefts?
neurotransmitter transporters (reuptake), enzymatic degradation, uptake by glial cells (astrocytes)
How do postsynaptic potentials influence the postsynaptic memrane?
through general summation
What type of summation occurs at different locations in the membrane?
spatial summation
What type of summation occurs at the same location but in rapid succession?
temporal summation
How does integration of info occur?
through summation of postsynaptic potentials
How do NTs and neuromodulators cause action?
directly on ion channels (ionotropic) or indirectly activating proteins inside post-synaptic neuron (metabotropic)
What is released into extracellular fluid to adjust the activity of many neurons?
neuromodulators
What type of neurotransmitters act directly (ionotropic)?
fast-acting (acetylcholine, glutamate, GABA)
What type of nts act indirectly (metabotropic)?
slow-acting (dopamine, serotonin)
T/F do neuromodulators manifest more slowly but longer than nts?
TRUE
What is one of the most common neuropeptides?
substance P
What is the job of substance P?
stimulates nerve endings at the site of injury and carries info from the spinal cord to the brain
What is a prominent modulator that responds to pain syndromes?
substance P
How do synaptic receptors produce actions?
directly (single unit with ion channel) and indirectly (cascade of intracellular molecules)
What are the three mechanisms postsynaptic receptors use to transduce signals?
directly open ion channels, indirect ^, indirectly activating a cascade
Metabotropic receptors release what that binds to specific ion channels to open them?
G-proteins
What system is responsible for the most profound and long-lasting changes in the nervous system?
G-protein Second-messenger System
What three things do second-messenger systems activate?
genes that change quantities of nts and receptors, opening of ion channels, regulate CA2+ concentrations
What is the major nt of the PNS?
Acetylcholine
What nt is utilized at the neuromuscular junction?
acetylcholine
What are the two categories of ACh receptors?
nicotinic (ionotropic at NMJ) and muscarinic (metabotropic like G-protein receptors)
What diseases does acetylcholine contribute to?
myasthenia gravis and alzheimer’s
What is the main excitatory nt of CNS?
glutamate
What conditions does glutamate contribute to?
depression and epilepsy
What is the most common fast-acting inhibitory nt?
GABA
What GABA receptor is ionotropic and produces hyperpolarization?
GABAa (antianxiety and sedation)
What GABA receptor is slow acting via second messenger?
GABAb (baclofen; muscle relaxant)
What nts inhibit neurons involved with the perception of pain?
opioids
What is a slow-acting nt that suppresses Ca2+ channels?
dopamine
Low levels of dopamine is associated with what disease?
Parkinson’s disease
High levels of dopamine is associated with what disease?
schizophrenia
What drug interferes with dopamine reuptake?
cocaine
What nt is involved with the fight or flight response?
norepinephrine
What are the two major norepinephrine subtypes?
A receptors relax smooth muscle / B receptors contract cardiac muscle
What nt is responsible for general arousal level?
serotonin
What antidepressant inhibits serotonin reuptake?
Prozac
What are drugs that mimic the effect of nts?
agonists
What disease is caused by antibodies that attack nicotinic receptors in muscle cells?
myasthenia gravis
