Presynaptic Mechanisms

Question 1

Experiment used to prove Ca++ is responsible for NT release

Answer 1

Large squid synapse: - Block K+ with TEA - Block Na+ with TTX - Still get potential change from calcium

Question 2

blocks Ca++ channels

Answer 2

cadmium

Question 3

Represent experiment proving role of Ca++ in NT release

Answer 3

Question 4

Answer 4

Fluorescent microscopy measurement of presynaptic Ca 2+ concentration – a train of AP causes increase in Ca concentration that is revealed by dye

Question 5

Answer 5

microinjection of Ca into a squid giant presynaptic terminal triggers transmitter release shown as depolarization of the postsynaptic membrane potential

Question 6

Microinjection of BAPTA (EGTA also possibility), a Ca++, chelator into the presynaptic terminal preventing transmitter release:

Potential vs. Time

Answer 6

Question 7

microinjection of BAPTA (EGTA also possibility), a Ca++ chelator, into the presynaptic terminal preventing transmitter release

Current vs. time

Answer 7