Flashcards in 4 - Neurotransmitters Deck (20):
What is a receptor potential?
graded potential produced by activation of a sensory receptor, can be depolarizing or hyperpolarizing
What is postsynaptic potential?
release of vesicles at the presynaptic terminal as a response to an action potential, changing the postsynaptic potential; if excititory will be depolarizing and if inhibitory will be hyperpolarizing.
What are the similarities between receptor potentials and postsynaptic potential? (2)
both potentials are graded changes in membrane excitability that decay away from the site of stimulus.
membrane potential must reach threshold level at the critical point of the axon (initial segment, axon hillock) that contains the voltage-gated ion channels, otherwise no AP will be produced
What are the two possible mechanisms neurotransmitters have of influencing the postsynaptic cell?
Where are Ionotropic receptors located and how do they activate?
localized within the actual ion channel
Where are Metabotropic receptors located and how do they activate?
receptors are located at some point on the membrane but activate an ion channel some distance away via a second messenger system.
What does activation of a Metabotropic receptor to activate an ion channel?
some internal cellular mechanism that may be long acting via changes in enzyme/protein expression.
What are the 3 classes of compounds?
Are Fast Neurotransmitters ionotropic or metabotropic?
often associated with ionotropic receptors, although may also act on metabotropic receptors (such as catecholamines)
Are Fast Neurotrasnmitters Excitatory or Inhibitory? Example?
Excitatory (ACh, glutamate, epinephrine)
Inhibitory (GABA, glycine)
Are Neuropeptdies ionotropic or metabotropic? Examples?
metabotropic (enkephalin, calcium binding protein, substance P)
Are Fast Neurotransmitters, Neuropeptides, or Non-traditional neurotransmitters more complex AA peptides from small to large?
What are Non-traditional neurotransmitters?
nitric oxide, eiconasoids (prostaglandins, cannabinoids)
Do Fast Neurotransmitters, Neuropeptides, or Non-traditional neurotransmitters affect adjacent cells?
Neurotransmitters are co-localized with ___ in axonal terminals.
What is an example of Neurotransmitters co-localized with neuropeptides?
GABA/calbindin in the frontal lobe and GABA/paryalbumin in the occipital lobe
What is the function of colocalization? (2)
not clear but some indication is that the peptide acts as a neuromodulator by modifying the activity of the cell during neurotransmission,
as well as prolonging membrane activity.
T/F: the presynaptic receptor determines whether the neurotransmitter will be excitatory or inhibitory.
False: the POSTSYNAPTIC receptor determines whether the neurotransmitter will be excitatory or inhibitory.
what on the postsynaptic receptor determines whether the nerurotransmitter will be excitatory or inihibotory? example?
what type of ion channel the receptor is located on
Excitatory: Acetylcholine with Na+ channels
Inhibitory: GABA and glycine with Cl- channels