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term which implies they are involved w/ transmission of AP from one neuron to the next or to a mm cell or gland
Neurotransmitters are released from:
The neurotransmitter affects:
the postsynaptic membrane (neuron, MM cell, gland cell) in a specific manner in milliseconds
Are neurotransmitters excitatory or inhibitory?
- may be either
- some NT may have opposite effects on different types of neurons
What determines if a neurotransmitter is excitatory or inhibitory?
based on chemical nature of receptor
Can the same neuron have receptors for many types of NT?
Can NT respond to different inputs?
What are different receptors called?
What is the criteria of a NT?
- must be synthesized in the neuron and localized in the presynaptic membrane
- must be released into the synaptic cleft
- needs to bind to receptors of the postsynaptic membrane
- needs to be removed from receptor by specific mechanisms
Are the receptors of the postsynaptic membrane ligand or voltage gated channels?
What do the receptors of the postsynaptic membrane do?
control conductance of ions (hyper or hypopolarized)
What are the common neurotransmitter?
Is ACh excitatory or inhibitory?
majority of the time excitatory but can be inhibitory
Where is ACh found?
- neuromuscular junction
- all pre and post ganglionic parasympathetic neurons
What is ACh associated w/?
preganglionic sympathetic neurons
Is dopamine excitatory or inhibitory?
inhibitory in nature
Where is dopamine produced?
Where does dopamine end up?
in basal ganglia
What does dopamine do?
control muscle activity
What disease is dopamine associated with?
What is Parkinson's disease?
overactivity of dopamine (involuntary muscle contractions)
What part of the nervous system is serotonin involved w/?
Is serotonin excitatory or inhibitory?
What does serotonin impact?
emotion (depression, limbic, feelings)
What does GABA stand for?
gamma amino butyric acid
Is GABA excitatory or inhibitory?
major inhibitory NT in NS
Does GABA have lots of subtypes?
What does GABA cause?
inhibitory post-synaptic potentials
What does GABA bind to?
ligand gated channels to allow Cl in
What is glutamate?
an amino acid
Is glutamate excitatory or inhibitory?
major excitatory NT in NS
Glutamate is the cousin of?
What is glycine?
an amino acid
Is glycine excitatory or inhibitory?
usually inhibitory in spinal cord
Neuromodulators are chemicals that interact w/ pre and post synaptic membranes and are usually linked to:
G-protein and Second messenger systems
Are neuromodulators considered a fast or slow system when compared to NT?
slow (may take seconds, hours, or days to manifest)
Neuromodulators modulate rather than:
What is the function of neuromodulators?
- initial binding w/ receptor proteins (pre and post synaptic membrane)
- receptor contacts and activates molecules call G-proteins which are located inner layer of cell membrane
- G-proteins become involved w/ cAMP (cyclic adenosine monophosphate) which is called a second messenger molecule
- second messenger molecules set into action very complicated cascades of metabolic activity utilizing kinases and phosphorylation activity, influencing nature of the recptors
- increased activity results in changes in the biochemical nature of the neuron
What are the changes in the biochemical nature of the neuron form increased activity?
- produces changes in the molecular nature of the protein receptor modules resulting in opening or closing the channels, changing the sensitivity
- Alterations of gene expression (up or down regulation of genes)
- alteration of protein synthesis
- long term effects associated w/ memory and learning
What are some common neuromodulator molecules?
- neuroactive peptides
- adenosinenitric oxide
Although common neuromodulator molecules are found in all cells of the body, we are focusing on:
their context related to neurons
What are neuroactive peptides?
small protein molcules
What are some neuroactive peptides?
- substance P (pain processing)
- Endorphins (endogenous opiods)
- VIP (vasoactive intestinal polypeptides)
- about 40 others have been ID
What are the characteristics of receptors?
- determine sif a substance that binds to it will behave as NT or NM
- Receptor is always facing outward (w/ few exceptions) so they can interact w/ ligands
- protein molecules
- found on outer surface of cell membrane
- 2 Parts: binding component and ionophore component
- have multiple subunits
- ligand-gated channels
ACh to a nicotinic receptor on NMJ acts a a NT or NM
Ach to muscarinic receptor acts as NT or NM?
Binding component of a receptor:
active site, specific for different transmitter substances (TS)
pore component (protein pore through which the ions will flow)
bonding to NT; receptors which receive neurotransmitters
binding to NM; receptors which receives neuromodulators
What are the properties of amino acid ligand gated channels?
- pharmacology of the binding sites
What is the pharmacology of the binding sites of amino acid ligand gated channels?
- channels, pores, receptors
- which neurotransmitters influence the receptors as well as drugs
What are the kinetics of amino acid ligand gated channels?
binding process and channel gating and ultimately the duration of the effect (gating process- rate of interaction)
What is the selectivity of amino acid ligand gated channels?
- which ions will flow through receptor?
- IPSP or EPSP?
What is the conductance of amino acid ligand gated channels?
- magnitude of the effect
- quantity of ions passing through