Blocking of impulse conduction in peripheral nerves by local cooling as a routine in animal experimentation.

Small thermodes, cooled by the Peltier effect and heated by transistor dissipation, were developed for reversible nerve blocking. Temperature control is achieved by an electronic feedback circuit for two thermodes independently. This enables simple operation of the cooling system during animal experimentation. Any nerve temperature between 0 and 37 degrees C can be obtained within 90 s and maintained within 0.2 degree C. The instrument can be used both as a stand alone apparatus or under computer control. Effects of local cooling of the cervical vagus nerve of the rabbit on the A-wave of the compound action potential and on spontaneous activity are given as examples of application of the cooling system in biological experiments.