Fig. 2. Extracellular recordings from mouse tooth nociceptors in a novel jaw-nerve preparation.

(Top) Illustration of mouse head with jaws and their innervation. The mandible-inferior alveolar nerve preparation is derived from the lower jaw and transferred to an organ bath consisting of an external solution and a mini-tube that is connected to a temperature-controlled application system. Connection of the application system’s heating coil to a heating/cooling thermostat board permits rapid exchange of solution temperature in the mini-tube, where the preparation is exposed to chemical compounds and cold temperatures. Both the external and internal bath are supplied with oxygenized extracellular solution. Because of the short length of the inferior alveolar nerve, suction electrodes from glass capillaries are applied and the amplifier is used in a single-ended configuration. The external bath is required to prevent cold block in the nerve when the teeth in the mini-tube are exposed to cold. Action potentials from the inferior alveolar nerve are recorded in gap-free mode with Spike 2 (Materials and Methods).