This proposal requests funds for the purchase of a Zeiss inverted microscope and accessories. The microscope will be used to: l. Evaluate the cytostructural and secretory properties of cultured rat pituitary cells in order to determine whether subpopulations of gonadotropin secreting cells are differentially recruited to release hormone during periods of continuous hormonal stimulation, 2. Quantitate changes in endothelial cell morphology and migration behavior in response to activated human peripheral blood mononuclear cell factor, 3. Identify and study ion channel distributions on cultured myocardial and vascular smooth muscle cells, 4. Study the transfer of fluorescent dyes between coupled myocardial cells and to obtain cellular morphometric data, and 5. Evaluate the functional properties of acetylcholine containing ventral horn neurons. The microscope and accessories will benefit the faculty of the Department of Physiology and will allow the department to expand and broaden its basic research potential in electrophysiology.