This shared instrumentation grant application requests funds to purchase a Solamere QLC100 rapid planar confocal imaging microscope. Funds are requested to replace a Noran Oz laser-scanning confocal microscope that was purchased by University of Tennessee Health Science Center (UTHSC) funds 6 years ago. Currently, the Noran Oz at the UTHSC is in constant need of repair, is no longer serviced by the original manufacturer, and is serviced at high cost with a dwindling, finite supply of old Noran parts. The loss of rapid planar imaging capabilities threatens several currently NIH-funded projects at the UTHSC and the potential for future research discoveries. A group of 7 NIH-funded researchers will be the major users of the requested instrumentation. These investigators have NIH-funded projects that require the use of rapid planar confocal imaging. The requested instrument will be used to measure rapid changes in intracellular fluorescence at high spatial resolution in living cells. The applicant group will image local and global intracellular calcium (Ca2+) transients in smooth muscle cells, astrocytes, neurons and mammalian expression systems and study the intracellular movement and relocalization of signaling molecules and receptors within cells. Local and global intracellular Ca2+ transients and cellular protein translocation can occur within milliseconds and over short distances. In order to study and understand physiological functions of these signaling pathways, the applicant group requires an instrument with the ability to acquire fluorescent planar images with high spatial resolution and millisecond temporal resolution. The Solamere QLC100 acquires 512x512 images at a rate of 60 frames per second, a major requirement for these studies. Few other commercially available microscopes can provide this rapid imaging capability, but those that can are far more expensive than the Solamere instrument. Confocal microscopes available in the Memphis area, other than the faulty Oz system at UTHSC, can only acquire one image per second, which is inadequate for studies of the applicant group. Minor users will be encouraged to use the equipment on a fee- for-use basis to broaden the availability of this technique throughout the Memphis area. We estimate that the Solamere QLC100 will be used for approximately 60 hours per week. Relevance. Pathological alterations in rapid cellular signaling pathways that are studied by the applicant group lead to diseases ranging from hypertension, stroke and respiratory damage, to Alzheimer's disease, alcohol abuse and cancer. The requested instrumentation will provide UTHSC investigators with the continued capability to investigate and understand rapid cellular signaling pathways, alterations in which cause severe morbidity and mortality. ? ? ?