People / Graduate Students

Christine Graham

My work investigates the role of a neuroendocrine, stress-response signaling pathway in the inner ear.  Recently, urocortin was added to the list of neuropeptides present in the efferent neurons descending from the brainstem to the cochlea.  Urocortin acts through two G protein coupled receptors, corticotropin releasing hormone receptor 1 and 2 (CRHR1 and CRHR2), both of which are expressed in the inner ear.  These receptors are well characterized for their roles in modulating the systemic response to stress via the hypothalamic-pituitary-adrenal (HPA) axis, and several studies have indicated a role for these receptors in mediating local stress responses, independently of the HPA axis.  Nevertheless, the role of this neuroendocrine system in the inner ear remains unknown.  Using CRHR1 null mice, I examine how the absence of this signaling pathway influences auditory physiology, development, and biochemistry.  In particular, I explore the possibility that signaling through CRHR1 plays a dual role in the cochlea, guiding the development of proper innervation structure and protecting against noise-induced trauma.