BC-535 Preliminary, Rev. 060126
41
reset
– An operation wherein the collected charge on the integrating capacitor in the headstage is
dissipated, readying the system for further use.
signal polarity
– Defined as the sign applied to a current generated through a membrane in the
presence of an applied holding potential. The electrophysiological definition is determined by the
membrane such that an outward directed current and a depolarizing potential are both positive.
single channel
– Refers to a solitary channel protein functioning within a measurement milieu.
step potential
– A functionally instantaneous change in potential from one value to another.
time constant
– In a system governed by exponential kinetics this is the time required for a value to
change to 1/e of its initial value, where e=2.71828 is the base of the natural logarithm.
transient
– Momentary.
transmembrane
– That which spans a membrane or is referred from one side of a membrane to the
other.
trim pot
– An adjustable variable resistor used for making fine adjustments to a circuit.
TTL
– Transistor, Transistor Logic. Voltage ranges used to define an on or off state in binary devices.
0-0.8 V defines a logic 0 state and 2.4-5.0 V defines a logic 1 state.
unitary channel conductance
– A measure of the ability of a channel to pass an ion from one side of the
membrane to the other. An intrinsic property of a single channel which depends on the ionic
species under consideration. Determined by measuring the current through an open channel in
the presence of a driving force (transmembrane potential) at different potentials. Measurements
made within the Ohmic range of the channel’s response will graph as a straight line. The slope of
this line when plotted as current (I) vs. potential (V) will yield the conductance (or inverse
resistance) of the channel under these conditions.
V
m
hold
– The transmembrane potential generated by the amplifier and applied to the headstage. This
driving force appears in addition to any other driving forces which may be present.
V
C
– The user selected potential set in the
COMMANDS APPLIED TO REFERENCE
block of the amplifier.
Warner
Instruments
A Harvard Apparatus Company .
