Earl Carstens, Ph.D.

 Earl  Carstens, Ph.D.


  • Professor
  • Neurobiology, Physiology and Behavior

Pain and Itch Mechanisms

Research Summary

Our laboratory investigates neural mechanisms of oral and cutaneous chemical irritation, pain, itch and temperature sensation. We employ a variety of methodological approaches including human psychophysics, animal behavior, neuroanatomy, and electrophysiology including in vivo and in vitro neuronal recording. We currently have local collaborations with the departments of anesthesiology and pain medicine (Drs. Antognini and Jinks) and food science (Dr. O'Mahony) as well as international collaborations with Toyama University (Japan), University Paris 7, and Georgia State University (Rep. of Georgia).

Until recently, little was known about central nervous mechanisms underlying oral irritation. We employ a multidisciplinary approach to investigate the sensory effects of irritant chemicals, such as capsaicin (from red chili peppers), menthol (from mint), cinnamic aldehyde (from cinnamon), mustard oil, and carbonation and other agents causing tingle. Ongoing studies address the extent to which the temporal response characteristics of trigeminal and spinal cord neurons parallel human irritant sensations, as well as possible transduction mechanisms involving the recently-discovered family of thermosensitive TRP (transient receptor potential) ion channels.

Another research area that has until recently received little attention is itch. We use behavioral and neurophysiological approaches to address the question of whether or not itch and pain sensations are conveyed by separate neural pathways and how these sensory qualities interact. Of particular interest is the ability of several itch mediators (proteases, serotonin, histamine) to elicit prolonged scratching behavior in rodents and excitation of superficial spinal dorsal horn neurons over comparable time courses.

Select Publications

Sawyer CM, Iodi Carstens M, Simons CT, Slack UJ, McCluskey TS, Furrer S, Carstens E. Activation of lumbar spinal wide-dynamic range neurons by a sanshool derivative. J Neurophysiol. (in press), 2009.

Merrill AW, Cuellar JM, Judd JH, Iodi Carstens M, Carstens E. Effects of TRPA1 agonists mustard oil and cinnamaldehyde on lumbar spinal wide dynamic range neuronal responses to innocuous and noxious cutaneous stimuli in rats. J. Neurophysiol. 99(2):415-425, 2008.

Barter LS, Mark LO, Jinks SL, Carstens EE, Antognini JF. Immobilizing Doses of Halothane, Isoflurane or Propofol, Do Not Preferentially Depress Noxious Heat-Evoked Responses of Rat Lumbar Dorsal Horn Neurons with Ascending Projections. Anesth Analg. 106(3):985-990, 2008.

Albin KC, Carstens MI, Carstens E. Modulation of Oral Heat and Cold Pain by Irritant Chemicals. Chem Senses 33(1):3-15, 2008.

Dutton RC, Cuellar JM, Eger, EI, Antognini JF, Carstens E. Temporal and Spatial Determinants of Sacral Dorsal Horn Neuronal Windup in Relation to Isoflurane-induced Immobility. Anesthesia & Analgesia 105 (6):1665-1674, 2007.

Zanotto K, Merrill AW, Iodi Carstens M, Carstens E. Neurons in superficial trigeminal subnucleus caudalis responsive to oral cooling, menthol and other irritant stimuli. J. Neurophysiol. 97(2):966-78, 2007.

Simons CT, Boucher Y, Iodi Carstens M, Carstens E. Nicotine suppression of gustatory responses of neurons in the nucleus of the solitary tract. J Neurophysiol. 96: 1877-1886, 2006.

Dutton RC, Iodi Carstens M, Antognini JF, Carstens E. Long ascending propriospinal projections from lumbosacral to upper cervical spinal cord in the rat. Brain Research 1119, 76-85, 2006.


Mollecular Cellular and Integrative Physiology