Examination of the properties of nociceptive neurons, identifying neurons as nociceptive or non-nociceptive according to their responses to natural stimuli. Properties examined include membrane properties, firing patterns, ion channels and receptors determined immunocytochemically or by voltage clamp techniques. We are carefully examining how these properties alter in models of chronic pain, and thus how they may contrinute to chronic pain. This information is intended to help the much needed development of novel analgesics.