Associate Professor, Division of Medical Sciences
Research area: Ultrastructure of brain synapses
Do you ever wonder how exactly the brain changes in the face of stress, disease, and injury? UVic’s neuroscientist and assistant professor of histology, Dr. Patrick Nahirney, does and he’s working hard to find the answers.
When he’s not in the classroom, instructing undergraduate medical students, or in his office, writing up his latest research findings (in addition to his recently published 536-page textbook, Netter’s Essential Histology), Dr. Patrick Nahirney can be found working in the University of Victoria’s Division of Medical Sciences’ laboratory.
Nahirney’s current goal is to create high resolution, panoramic images of the brain at various stages of development — essentially a Google map of the brain — by piecing together digital snapshots of normal and diseased brain tissue that has been magnified up to 10,000 times under a powerful electron microscope. The resulting multi-colored images are so detailed that it is possible to count, not only the number of synapses present in the tissue sample, but also the number of vesicles delivering the chemical messengers within them.
A sample of Nahirney’s work, which he is in the process of publishing, can be pre-viewed at the following link:
By studying the structural and molecular development of the brain, Nahirney hopes to understand more about the mechanisms of synaptic transmission. He is particularly interested in the ultra structure of the synapse, the brain’s equivalent of a traffic intersection, where the chemical contents of vesicles (tiny sacs that travel across the synaptic gap between adjacent neurons) act like traffic lights that facilitate or inhibit the progression of electrical messages that travel along a web of neuronal pathways. These messages carry a wide range of information that may trigger a host of diverse outcomes, from the solidification of a memory, to the movement of a limb, or even a more subtle hormonal change.
One of Nahirney's areas of research focuses on the sub cellular, structural changes that occur in the hippocampus, a highly plastic region of the brain responsible for memory. By looking more closely at the synaptic cleft, the post-synaptic density, and vesicles responsible for signal transmission, Nahirney hopes to understand how stressors and neurological disease impact learning and memory processes. Is it the number of synapses present, the size and shape of the vesicles and volume of neurotransmitter within them, or the proportion of excitatory and inhibitory synapses that impact an individual’s level of intelligence and capacity for memory?
Nahirney is also looking at the structural consequences of strokes, particularly in a zone found within 0.5 mm of a stroke’s epicenter. Nahirney has found this zone to be ripe with structural changes to both the support cells of the brain, such as astrocytes, and the mitochondria — little energy factories — of the neurons themselves. Nahirney has discovered that, in an effort to keep the remaining neurons alive in the absence of adequate blood flow, the astrocytes begin to stockpile glycogen in order to compensate for the oxygen-deprived mitochondria that are no longer capable of supplying the damaged cells with essential energy. In fact, Nahirney has observed that the swelling in size of these astrocytes is one of the first structural changes to occur following a stroke.
Nahirney has also been researching the effects of ethanol on brain development and the structural changes associated with fetal alcohol syndrome. Nahirney and his undergraduate student, Brianne Lindsay, found that prenatal ethanol exposure in rats was associated with both a reduction in cell body size and synaptic structural aberrations that become more difficult to detect as the brain continues to develop over time.
Nahirney’s newest research project involves ‘live cell’-imaging of neuron development in the presence of various nutraceuticals, including dietary supplements such as Omega 3.
Given the astounding costs of equipping and running a research laboratory, which boasts a microscope that retails for over half a million dollars, Nahirney is keen to acknowledge the assistance of key funders that include: the Canadian Foundation of Innovation, UVic’s Division of Medical Sciences, and the Natural Sciences and Engineering Research Council of Canada.
He is also quick to acknowledge the contributions of his colleagues, including Dr. Craig Brown, Dr. Brian Christie, and Dr. Leanne Swayne, as well as his dedicated research assistants.
Ultimately, Nahirney hopes to produce a structural and molecular framework of brain development; a framework upon which the clinical world of medicine might build new and more effective ways of diagnosing, preventing, and treating life-altering brain injuries and diseases.