The Paw Pressure Analgesia Instrument is for the Randall-Selitto test, which requires the application of increasing pressure on the paw between a flat surface and a blunt pointer. It is usually used with animals with one paw inflamed by an injection, and one normal paw, to evaluate drugs for analgesic action.

Principle of Operation
The device exerts a steadily increasing force (16 grams per second) on the rat paw until the animal makes a stereotyped flinch response. The researcher releases a foot pedal to stop the force indicator. The electronics measures the time interval between the start of the slide motion and the moment the slide is stopped by the operator and converts time into force.
The force is measured on the scale calibrated in 10-gram steps, by a pointer riveted to the slide. The scale can be multiplied by 2 or 3, by placing one or two disc weights on the slide.

Data Acquisition
This new design includes a removable foot pedal cord and a cable connection for data collection to the 2600 recorder/printer ( optionnal). The data, stored in the 2600 internal memory and shown on its graphic display, can be printed out in real time and/or routed to the computer; in the latter case, the 52010 Win-DAS Software is required.