11
3.1.6 Mounting step six
• Carefully move the jaws together while ensuring that the second mounted wire lies underneath the first one secured on the
left-hand jaw (figure 3.6 A). The procedure clamps the second wire to prevent it from damaging the vessel segment when
securing the wire to the right-hand jaw (connected to the transducer). Secure the near end of the wire in a clockwise direc-
tion under the far fixing screw on the right-hand jaw (figure 3.6 B).
Figure 3.6 A and B Mounting step 6
A
B
3.1.7 Mounting step seven
• Secure the far end of the wire under the near fixing screw on the right-hand jaw. Again the wire is passed clockwise around
the screw stretching the wire as the screw is tightened (figure 3.7 A-B). Move the jaws apart to slightly stretch the vessel seg-
ment. Make sure that the vessel on the far side of the jaws does not extend beyond the jaws, as even a small extension will
affect the normalisation procedure. In case of excess of vessel on the far side of the jaws then move the jaws together again
and remove excessive tissue using a forceps as described in mounting step four. A better method for the skilled operator is
to move the jaws slightly apart and use scissors to make a small slit in the vessel wall where the vessel is clamped.
B
A
Figure 3.7 A and B Mounting step 7
3.2 Normalization
The importance of normalizing the preparation is three-fold:
1. Experiments with elastic preparations like vessels can only have meaning if they are performed under conditions where the
size is clearly defined.
2. Clearly defined conditions are required in pharmacological experiments as the sensitivity of preparations to agonists and
antagonists is dependent on the amount of stretch.
3. The active response of a preparation is dependent on the extent of stretch, which makes it important to set the preparation
to an internal circumference giving maximal response.
