Nerves regulate function and structure of peripheral cells. Target cells in turn provide molecular signals that govern the quantity and type of innervation they receive. Our research examines this interplay between nerve and target and the factors that govern neuronal growth and degeneration. We are especially interested in how this relationship is affected by gonadal steroid hormones such as estrogen. Ongoing projects examine mechanisms and consequences of neuroplasticity in peripheral tissues including: reorganization of cardiac innervation following myocardial infarction, which may contribute to sudden cardiac death; estrogen-induced remodeling of innervation of the reproductive tract; mechanisms by which nerve projections are pruned under normal and pathophysiological conditions; and the role of estrogen in the etiology of female pain syndromes.