The invention provides isolated non-selective cation channel proteins which are (a) activatable by noxious heat; (b) obtainable from human T lymphocytes; (c) not capsaicin sensitive, particularly the VR-L protein (Seq ID No. 2), plus or variants (e.g. homologues or fragments) thereof. Also provided are nucleic acids encoding these (e.g. Seq ID No. 1), or which have utility in probing, amplifying or down-regulating these. Methods of providing the proteins and nucleic acids are disclosed, as are vectors, host cells, and organisms utilising them, and antibodies. Also disclosed are methods of influencing the electrophysiological and/or pharmacological properties of a cell (e.g. by way of therapy) based on manipulation of the proteins or nucleic acids, and methods for screening for substances having ion-channel modulating activity (which may be potential analgesics or other compounds which affect nociception, immunomodulatory agents or neuromodulatory agents).