DEMO DEMODisplay of Results
Results are displayed on a simulated chart recorder showing longitudinal muscle tension (g) and fluid propulsion from a drop counter. Each drop causes a deflection of the pen on the pen recorder. At relatively low flow rates each drop is discernible. However at high flow rates and particularly after the peristaltic reflex test the flow rate may be so fast that it is impossible to measure from the tracing. In order to facilitate quantification of the flow rate under these circumstances the number of drops (an average from several experiments) is displayed as a number on the trace. Remember that it is important when assessing the effects of test substances that a comparison is made with the control (vehicle alone).
Control Responses
A control response to 0.2 ml 0.9% NaCl solution followed by 0.1 ml 0.9% NaCl solution is recorded. After two minutes the peristaltic reflex test is performed. The control solution causes slight stimulation of the preparation due to a transitory increase in intraluminal pressure during injection. This control response must then be taken into account when assessing the effects of test agents. Where saline is an unsuitable vehicle a control must be obtained for vehicle alone.
Test agents
Most test substances are dissolved in saline and administered in a volume of 0.2 ml washed in by 0.1 ml 0.9% NaCl. Acidified saline is used as the vehicle for epinephrine (adrenaline).
