This project, entitled Optical Molecular Imaging of Opioid Distribution and its Metabolic Effects in the Brain, set out to construct a new optical imaging microscope that was sensitive to not only microscopic structures of neurons (cells) in brain tissue, but also sensitive to the molecular composition and the metabolic dynamics that take place in these brain cells in health and after exposure to morphine, an opioid.  Because of the significant negative impact that opioids have had on individual lives and on our society, our goal was to develop and use new imaging technologies to image neurons and brain slices from a rodent model before and after exposure to morphine, to determine what changes occur.  The intellectual merit of our project consisted of new optical imaging technologies and ways to visualize the effects that opioids have on the brain.  We constructed several types of optical imaging systems and characterized their sensitivity, spectral resolution, and spectral fidelity.  We also applied our microscopy techniques to characterize the optical properties or signatures of opioids (morphine), so we could then look for these signatures and the presence of morphine in cells or tissues.  Our imaging showed the capacity to visualize metabolic brain cell activity after morphine treatment, and revealed different responses from different brain slice regions following the administration of morphine to the brain slice preparations.

We further worked to improve the sensitivity of our microscope by implementing a better detection process, and improve multi-modality capabilities by adding other optical signal channels.  This was done by adding more detectors and filters to the microscope so multiple channels could be detected simultaneously, allowing us to rapidly detect the metabolic activity within the cells or tissues.  For brain slice imaging, we improved parameters that allowed us to capture high-resolution images over larger areas of tissue.  This allowed us to image different parts of the rodent brain to study the morphine effects across different regions.  We then spent considerable time investigating morphine interactions with cultured neurons, isolated brain cells grown and maintained in a dish, since these were a much simpler system to investigate interactions and changes related to neuronal metabolism.

Finally, we focused on imaging at even higher resolution within single cells to understand the morphine effect on neurons and glial cell metabolism by tracking the sub-cellular movement and signals from mitochondria, parts of the cell that are responsible for powering cell function, including metabolism.  We constructed a hybrid microscope for simultaneous imaging and developed analysis methods to statistically quantify the amount and dynamics of metabolic changes happening in the cells. Using these tools, we found an increase in metabolic intensity and a decrease in mitochondria size by label-free imaging, when the neurons were exposed to morphine.  We correlated these observations and proposed the mechanism of how morphine interacts with neurons and glial cells in the brain.  The broader impact of our work will influence the fields of optical science and engineering, biophotonics, and neuroscience, as we learn more about the effects that opioids have on the brain structure, metabolism, and function.  In the future, our label-free imaging tools and discoveries will help scientists to better understand how opioids interact across many spatial scales, from the sub-cellular and cellular level with neurons and glia, as well as across larger connected brain regions.

Last Modified: 08/16/2020
Modified by: Stephen A Boppart