Michael E. O'Leary, PhD

Contact Dr.  O'Leary

900 Walnut Street
Philadelphia, PA 19107

(215) 503-9983

Research and Clinical Interests

Voltage-gated ion channels of primary sensory neurons

Sensory nerve fibers originate in the dorsal root ganglion and produce long branches that terminate in peripheral tissues. The termini of these sensory neurons elaborate specialized membrane bound proteins that convert mechanical, thermal, and chemical stimuli into electrical signals that are transmitted along the sensory nerve fibers back to the spinal cord. Included in these sensory nerve fibers are subsets of unmyelinated fibers that predominately respond to noxious/painful stimuli. These nociceptive nerve fibers are the initial link in the pain-sensing pathway. The research in my laboratory utilizes a combination of electrophysiology and molecular biology to investigate the mechanisms of sensory neuron transduction and the propagation of electrical signals along nociceptive nerve fibers. To do this we developed novel methodologies that permit electrical recording and genetic screening of individual sensory neurons. Quantitative analysis of the mRNA transcripts expressed in single nociceptors enables us to correlate the electrical properties with the specific proteins expressed in these neurons. Using this approach we have identified the several classes of voltage-gated ion channels that are uniquely expressed in nociceptors. Recent work indicates that these neurons exclusively express the Nav1.7, Nav1.8 and Nav1.9 sodium channel isoforms and that these channels underlie the electrical excitability of nociceptive neurons.

My laboratory utilizes state-of-art electrophysiology and molecular techniques including patch-clamp, two-electrode voltage clamp, immunofluorescence, confocal imaging, western blot, immunoprecipitation, and quantitative RT-PCR.

The long-term goal of our studies is to fully catalogue the ligand- and voltage-gated ion channels expressed in nociceptors. These findings will enhance our understanding of nociceptor function and serve as guides for designing novel strategies for treating acute and chronic pain.