Core C: The Two-Photon Microscopy and Confocal FRET/FRAP Imaging Core will: 1) Provide equipment and expertise to facilitate the use of the multiphoton microscopy for physiologic studies by PPG investigators. 2. Develop and apply advanced imaging techniques, especially FRET and FRAP on the MRC-1024MP, twophoton microscope and Gl Division confocal microscope (Zeiss 410). 3. Provide user training for imaging of cellular and tissue modes by multiphoton confocal microscopy. 4. Provide on-going support for experimental design, developing new techniques (now including FRET and FRAP), methods of analysis, and reviewing experimental results related to Core C equipment. 5. Maintain multiphoton microscope Web page/sign-up program. 6. Organize and maintain all equipment and usage records. 7. Provide data to Core A for charge-back of Core C use by non-PPG members of Hopkins community.