Block 4 Flashcards
post-synaptic region is a ___ excitable domain
chemically
the signal that open gates is a ___ signal
chemical
conductance of ions is regulated by the presence of the ___
neurotransmitters
when ions move across the post-synaptic membrane, you get ____
post synaptic potentials
small and variable changes in the membrane potential
post synaptic potentials
PSPs are produced by __, __, __, and __ channels
sodium, potassium, calcium, chloride
acquisition of positive e-charge in the post-synaptic neuron; helps axon hillock reach threshold
excitatory post-synaptic potential
acquisition or maintenance of a negative e-charge in the post-synaptic neuron; prevents the axon hillock from reaching threshold
inhibitory post-synaptic potential
postsynaptic increase in sodium and calcium conductance, decrease in potassium conductance, creates the ___ effect in the __ postsynaptic potential
excitatory
postsynaptic increase in potassium and chloride conductance creates the ___ effect in ___ postsynaptic potential
inhibitory
___ tends to hold membrane potential near its equilibrium potential, blocking depolarizing influence so it is considered inhibitory in nature
chloride
short circuits other positive influences in the area
chloride shunt
GABA receptor is a __ channel
chloride
dendritic reduction of all synaptic influences into action potential; sum of all positive and negative signals in the cell, with spatial and temporal summation taken into account
integration
synapses closer to the ___ are more influential
axon hillock
adding together of all EPSPs and IPSPs over space; closer to axon hillock, more influential
spatial summation
adding together of EPSPs and IPSPs over time; repetitive activation affects synaptic influence
temporal summation
the concept that a strong IPSP and EPSP will cancel each other
bidirectional
True or false: more IPSPs occur than EPSPs
true
IPSPs often occur in the absence of ___
excitation
a neurotransmitter receptor linked to a neighboring ion channel by an intracellular signaling molecule
metabotropic neurotransmitter receptor
___ binding site in a metabotropic receptor activated an intracellular signaling molecule when the binding site is occupied by a neurotransmitter
ligand
used to open gates when the binding site is occupied by a neurotransmitter in metabotropic receptors
intracellular signaling molecule
a neurotransmitter receptor that is a neurotransmitter-gated ion channel
ionotropic neurotransmitter receptor
ionotropic neurotransmitter receptors possess a __ binding site and a __ that opens or closes when binding site is occupied by a neurotransmitter
ligand; gate
examples of ionotropic neurotransmitter receptors
nicotinic acetylcholine, GABA receptors
molecule that binds to a receptor
ligand
the concept of neurotransmitters rapidly bouncing on and off of neurotransmitter receptors
continuum of efficacy
how fast a ligand binds to a receptor
affinity
how biologically effective a ligand is once bound to a receptor
potency
ligands that bind to a receptor and activate it biologically; produce PSP in target neuron
agonist
ligands that bind to a receptor but do not activate it biologically; high affinity so receptor is literally blocked from functioning
antagonists
all antagonists are ___
exogenous (not created by the body)
excitation/inhibition are properties of the ___
receptor
nature of synaptic potential is determined by the ___ by which receptor it chooses to use
post-synaptic cell
bind to a receptor in a different location than agonists and antagonists; increase affinity for binding to a ligand
allosteric modifiers
synthesized in the pre-synaptic terminal by ChAT, which fuses acetate and choline together
acetylcholine
ChAT
cholineacetyltransferase
receptors become less responsive to presence of the agonist; used to terminate ACh stimulated PSPs
desensitization
moving away from synaptic cleft; used to terminate ACh stimulated PSPs
diffusion
enzymes __ the transmitter molecule; used to terminate ACh stimulated PSPs
break down
enzyme used in ACh breakdown
acetylcholinesterase
naturally occurring drug that blocks AChE
physostigmine
manmade AChE blockers
insecticides
ACh acts at the interface between nerve and muscle called the ___
neuromuscular junction
most commonly employed neurotransmitter in the brain; produces inhibition by activating a gK or more often a gCl
GABA
neurotransmitter synthesized from glutamate by glutamic acid decarboxylase
GABA
recycles GABA back to glutamate for reuptake and use
GABA transaminase
at least 2 ___ binding sites on the GABA receptor, one site for benzodiazepines and another for barbiturates
allosteric
majority of synapses in the brain are inhibitory, therefore are ___
GABAergic
many synapses use ___, using GABA to block synaptic terminal from incoming action potentials
presynaptic inhibition
GABA antagonists produce ___
excitation
loss of GABA producing neurons causes ___, which is treated by ___
epilepsy; GABA allosteric agonists
chemically similar to GABA, but mediates more excitation in the brain
glutamate
__ and __ are main excitatory neurotransmitters; both are present in all cells as amino acids
glutamate and aspartate
glutamate/aspartate mediated cell death
excitotoxicity
important amino acid for inhibition, especially in the spinal cord, where it is used instead of GABA
glycine
glycine is blocked by ___, causes spinal seizures
strychnine
synthesized from the amino acid precursor tyrosine
catechloamines
rate limiting enzyme that synthesizes DA, NE, and E from tyrosine; produces negative feedback and shuts off DA and NE synthesis
tryosine hydroxylase (TOH)
synthesized from the amino acid precursor tryptophan
indolamines
enzyme that synthesizes the neurotransmitter DA from L-Dopa, also responsible for producing serotonin
5HTP Decarboxylase = AAA decarboxylase
a long chain of amino acids is called a __, a short chain is a __
protein; peptide
peptides released into the brain and used as a neurochemical signal between neurons
peptide neurotransmitters
peptides released from the brain into the blood stream acting as neurochemical signals between brain and body
peptide hormones
how peptides are synthesized and packaged into vesicles in the soma and sent down the axon to synaptic terminal
orthograde axoplasmic transport
peptide transmitters are metabolically expensive, so they tend to act at low concentrations for a long period of time, so they are called ___
neuromodulators
family of peptides that act as natural pain killers
endorphins/enkephalins
peptides involved in social recognition, aggression, nurturing, affiliation, water retention, and other CNS functions
vasopressin and oxytocin
peptides are often __ (released with other neurotransmitters)
co-transmitters
substance that acts by modifying the affinity of a receptor for another transmitter (allosteric modification)
neuromodulator
