An automatic electronic apparatus for generating and recording a ramp stimulus for analgesia testing

Analgesia testing is conveniently done by applying an electrical stimulus to the tooth pulp of an animal that, in sufficient strength, causes an observable response. The difference in stimulus strength required in treated and control animals is an effective measure of analgesia, if the conditions can be sufficiently standardized. We describe an apparatus which generates a ramp stimulus at a controlled rate, allows accurate determinations of the response voltage with a digital readout, allows holding a reading to determine whether the response is a valid one, and automatically terminates the stimulus when the maximum voltage is reached. This apparatus was constructed from readily available components and can easily be modified to produce various ramp speeds, modulation frequencies, and maximum voltage outputs.