Ellen A. Lumpkin

Molecular and cellular mechanisms of mechanosensory transduction in touch and pain receptors

The goal of our research is to determine how somatosensory neurons detect and respond to mechanical stimuli in humans and other vertebrate animals. Somatosensory neurons innervate the body and are responsible for our perception of touch, pain, and proprioception (the awareness of our limb position that is necessary for coordinated movements such as walking). These senses are essential for survival because they allow an animal to constantly monitor its surroundings so that it can react quickly to changing situations. Their importance to human health is underscored by diseases, such as diabetes and AIDS, that cause the death of somatosensory neurons. Patients with these diseases cannot feel injuries, thus, even minor insults can lead to permanent tissue damage.

Although touch, pain and proprioception are distinct senses, they are all initiated by mechanical stimulation of somatosensory neurons. Furthermore, cells that detect mechanical stimuli are responsible for our senses of hearing and balance, as well as for basic physiological processes such as blood pressure regulation, bladder function and bone mineralization.

Because vertebrate somatosensory receptors are quite diverse and are scattered throughout the body, studying their mechanisms of mechanotransduction is technically challenging. As a result, we know almost nothing about how somatosensory neurons detect and respond to mechanical stimulation. To overcome these difficulties, my laboratory focuses on mechanoreception in the Merkel cell-neurite complex, a very sensitive type of vertebrate touch receptor that we can identify in living preparations. We use biophysical techniques to directly observe how individual, living touch receptors respond to skin pressure. We also employ molecular genetic approaches to identify molecules that allow mechanoreceptor cells to function.

Selected Publications

Lumpkin EA, Hudspeth AJ (1995) Detection of Ca²⁺ entry through mechanosensitive channels localizes the site of mechanoelectrical transduction in hair cells. Proceedings of the National Academy of Sciences U.S.A. 92:10297-10301.

Burlacu S, Tap WD, Lumpkin EA, Hudspeth AJ (1997) ATPase activity of myosin in hair bundles of the bullfrog's sacculus. Biophysical Journal 72:263-271.

Lumpkin EA, Marquis RE, Hudspeth AJ (1997) The selectivity of the hair cell's mechanoelectrical-transduction channel promotes Ca²⁺ flux at low Ca²⁺ concentrations. Proceedings of the National Academy of Sciences U.S.A. 94:10997-11002.

Yamoah EN, Lumpkin EA, Dumont RA, Smith PJ, Hudspeth AJ, Gillespie PG (1998) Plasma membrane Ca²⁺-ATPase extrudes Ca²⁺ from hair cell stereocilia. Journal of Neuroscience 18:610-624.

Lumpkin EA, Hudspeth AJ (1998) Regulation of free Ca²⁺ concentration in hair-cell stereocilia. Journal of Neuroscience 18:6300-6318.

Lumpkin EA, Collisson T, Parab P, Omer-Abdalla A, Haeberle H, Chen P, Doetzlhofer A, White P, Groves A, Segil N, Johnson JE (2003) Math1-driven GFP expression in the developing nervous system of transgenic mice. Gene Expression Patterns 3:389-395.

Haeberle H, Fujiwara M, Chuang J, Medina MM, Panditrao MV, Bechstedt S, Howard J, Lumpkin EA (2004) Molecular profiling reveals synaptic release machinery in Merkel cells. Proceedings of the National Academy of Sciences U.S.A. 101:14503-14508.

Lumpkin EA, Bautista DM (2005) Feeling the pressure in mammalian somatosensation. Current Opinion in Neurobiology 15:382-388.

Siemens J, Zhou S, Piskorowski R, Nikai T, Lumpkin EA, Basbaum AI, King D, Julius D (2006) Spider toxins activate the capsaicin receptor to produce inflammatory pain. Nature 444:208-212.

Contact Information

Ellen A. Lumpkin, Ph.D.

Department of Neuroscience

Baylor College of Medicine

One Baylor Plaza

Houston, Texas 77030, U.S.A.

Tel: (713) 798-3418

Fax: (713) 798-3946

E-mail: lumpkin@bcm.tmc.edu