University:
Binghamton University
Course:
BIOL 313 | Cellular Neurobiology
Academic year:

2024
Views:

128

Pages:

2
Author:

CrystalMintah

EXAM #2 Chemicall Synaptic Transmission a. Presynaptic cell fires an action potential b. Vesicles carrying neurotransmitters - Ca2+ is required c. Neurotransmitters bind a receptor on the postsynaptic membrane d. This binding opens an ion channel resulting in either I. depolarization II. If it crosses the threshold and gets the postsynaptic cell to fire an action potential (these channels are not the same as voltage-gated channels) a. Open for neurotransmitters b. Not a voltage channel Postsynaptic responses may be called EPP (end plate potential) - which refers to muscle cells that on the postsynaptic cell ➔ (EPSP ) excitatory postsynaptic potential: bings Vm to threshold ➔ (IPSP) inhibitory postsynaptic potentials: brings Vm away from the threshold ➔ (PSP) postsynaptic potential A PSP is not an action potential - can create one but is not one itself a. It declines in amplitude once it is made over time, dictated by time (t), and declines over distance, as determined by the length constant (λ) Say you have identified a neurotransmitter - it opens up a channel type that allows ions to pass. What ions are they? a. For the neurotransmitter junction, Ach is used using a voltage-clamp configuration in your patch clamp I. Apply Ach to the cell membrane and record the current II. So you hold Vm to -60mV which is the resting potential Ach channel is equally permeable to NA+ and K+ a. So, where do you get no net current when Vm is clamped halfway between the equilibrium potential for sodium and potassium or (ENa+EK/2) b. This idea is the reversal potential Vrev If Na+ and K+ are not equally permeable - say Na+ is 3x more permeable than K+ , then the equation will be