18
3.3.1 PRINCIPLES OF THE NORMALIZATION PROCEDURE
In practice the normalization is performed by
distending the segment stepwise and measuring
sets of micrometer and force readings (figure 3.8).
These data are converted into values of internal
circumference (μm) and wall tension T (mN/mm)
respectively.
Plotting wall tension against internal
circumference reveals an exponential curve and
by applying the isobar curve corresponding to
100 mmHg, IC
100
is calculated from the point of
intersection using the Laplace relation (figure 3.9).
IC
1
is calculated from IC
100
by multiplying a factor,
the Norm Factor, giving an internal circumference
at which the active force production as well as the
sensitivity to agonists of the segment is maximal.
For rat mesenteric arteries the Norm Factor is
0.9 but both this factor as well as the transmural
pressure has to be optimized for each particular
segment. The normalized internal diameter is
calculated by dividing IC
1
with
.
3.3.2 THE AUTOMATED NORMALIZATION PROCEDURE ON THE 630MA SYSTEM
Make sure the wires/pins do not touch and are
close together without touching
1. Zero the force of the Chamber going to be
normalized automatically.
2. Go into the Norm. Set-up menu.
NORMALIZATION SETUP
SELECT
SELECT
SELECT
SELECT CHAMBER 1:
ENTER
SELECT
SELECT CHAMBER 2:
SELECT CHAMBER 3:
SELECT CHAMBER 4:
Содержание 630MA
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