The methods and compositions of the invention are based on a method for measuring nociceptive responses in vertebrates, including humans and other mammals utilizing a newly discovered thermoreceptor belonging to the Transient Receptor Potential (TRP) family of non-selective cation channels that participates in thermosensation and pain. This receptor, designated ANKTMI, is associated with nociceptive pain, such as hyperalgesia. Accordingly, the invention provides isolated polypeptides and polynucleotides associated with nociception as well as methods for identifying or screening agents that modulate nociception.