Cellular neuroscience, comparative neurobiology, electrophysiology
Ph.D., Wright State University
What we do: We answer both applied and basic questions about how the nervous system helps animals survive in their environments. On the applied side, we study animals that evolved ways to avoid damage to the nervous system. We focus most of our efforts on challenges to the nervous system that tend to be big problems in many human diseases. These include inactivity of neuromuscular systems (think, “if you don’t use it you lose it”) and impaired oxygen transport (think, brain damage in stroke and cardiac arrest). By learning from animals that already “know” how to get around these problems, we up our chances of finding new solutions. On the basic side, we use this approach to make new discoveries about how nervous systems use plasticity to help animals adapt to their environments. To do this, we take fundamental concepts about plasticity that were developed outside of real-life contexts (e.g., cell culture, lab settings, modeling, etc.) and test how they work in situations where animals may need them to survive. This allows us to put together new ideas about how these processes are important for behavior and why they may have evolved.
How we do it: We tend to ask questions using the neural system that regulates breathing in amphibians for two reasons. First, breathing is a tractable, rhythmic behavior that is easily studied across scales of organization (genes to proteins to cells to networks to behavior) compared to other behaviors like learning and memory. Second, amphibians have interesting life history traits that allow us to ask questions about how different forms of plasticity have adaptive importance in nature. On the technical side, we use an integrative approach that spans whole animal behavior down to the molecular biology of single neurons. We use a range of tools that include patch-clamp electrophysiology to study electrical properties of neurons, single-cell quantitative PCR and RNA sequencing to assess gene expression in individual neurons, in vivo measurements of behavior (measurements of breathing and EMG to record muscle activity), extracellular recording to measure circuit activity, and fluorescence imaging microscopy.
Research Opportunities: Graduate Students– We are looking for enthusiastic and creative graduate students (MS and PhD). A background in neurophysiology and general physiology is a plus. A background in patch-clamp electrophysiology is an even bigger plus. If you are interested in joining us, please send an email to email@example.com with your C.V. and two references. Please be sure to check out some of the recent publications listed below and give a description of why this work interests you when you send an email.
Adams, S., Zubov, T., Bueschke, N., & Santin, J. M. Neuromodulation or energy failure? Metabolic limitations silence network output in the hypoxic amphibian brainstem. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 2020. In press. doi.org/10.1152/ajpregu.00209.2020
Northcutt, N.J., Kick, D.R., Otopalik, A.G., Goetz, B.M., Harris, R.M., Santin, J.M., Hoffman, H.A., Marder, E., Schulz, D.J. Molecular profiling of single neurons of known identity in two ganglia from the crab Cancer borealis. Proceedings of the National Academy of Sciences. 2019. doi: https://doi.org/10.1073/pnas.1911413116
Santin, J.M. Motor inactivity in hibernating frogs: Linking plasticity that stabilizes neuronal function to behavior in the natural environment. Developmental Neurobiology. 2019, in press doi: https://doi.org/10.1002/dneu.22721
Santin, J.M., Schulz, D.J. Membrane voltage is a direct feedback signal that influences correlated ion channel expression in neurons. Current Biology. 2019, 29; 1683–1688, doi: 10.1016/j.cub.2019.04.008
Vajello, M., Santin, J.M., Hartzler, L.K. Noradrenergic modulation determines respiratory network activity during temperature changes in the in vitro brainstem of bullfrogs. Respiratory Physiology and Neurobiology. 2018, 258; 25-31. doi:10.1016/j.resp.2018.10.002
Kempf, E.A., Rollins, K.S., Hopkins, T.D., Butenas, A.L., Santin, J.M., Smith, J.R., Copp, S.W. Chronic femoral artery ligation exaggerates the pressor and sympathetic nerve responses during dynamic skeletal muscle stretch in decerebrate rats. American Journal of Physiology- Heart and Circulatory Physiology. 2018. 314; H246-H254 doi: 10.1152/ajpheart.00498.2017
Santin, J.M. How important is CO2 chemoreflex for the control of breathing? Environmental and evolutionary considerations. Comparative Biochemistry and Physiology, Part A: Molecular and Integrative Physiology. 2018; 215, 6-19. doi: 10.1016/j.cbpa.2017.09.015
Santin, J.M., Vajello, M., Hartzler, L.K. Synaptic up-scaling preserves motor circuit output after chronic, natural inactivity. eLife. 2017; 6:e30005. doi: 10.7554/eLife.30005
Santin, J.M., Hartzler L.K. Activation of respiratory muscles does not occur during cold-submergence in bullfrogs, Lithobates catesbeianus. The Journal of Experimental Biology. 2017; 220, 1181-1186. doi: 10.1242/jeb.153544
Santin, J.M., Hartzler, L.K. Environmentally-induced return to juvenile-like chemosensitivity in the respiratory control system of adult bullfrog, Lithobates catesbeianus. The Journal of Physiology-London. 2016; 594; 6349-6367. doi: 10.1113/JP272777
Santin, J.M., Wang, T., Dukkipati, S.S., Hartzler, L.K. Commentary: The spinal cord has an intrinsic system for the control of pH. Frontiers in Physiology. 2016; 7:513. doi: 10.3389/fphys.2016.00513
Santin, J.M., Hartzler, L.K. Control of breathing following overwintering conditions in the American bullfrog, Lithobates catesbeianus. The Journal of Experimental Biology. 2016; 219; 2003-2016. doi: 10.1242/jeb.136259
Santin, J.M., Hartzler, L.K. Reassessment of chemical control of breathing in bullfrogs, Lithobates catesbeianus, using measurements of pulmonary ventilation. Respiratory Physiology & Neurobiology. 2016; 224, 80-89. doi: 10.1016/j.resp.2015.09.013
Santin, J.M., Hartzler, L.K. Activation state of the hyperpolarization-activated current (Ih) modulates temperature-sensitivity of firing in locus coeruleus neurons from bullfrogs. American Journal of Physiology- Regulatory, Integrative, & Comparative. 2015; 308, R1045-1061. doi: 10.1152/ajpregu.00036.2015
Imber, A.N., Santin, J.M., Graham, C.D., Putnam, R.W. A HCO3–-dependent mechanism involving soluble adenylyl cyclase for the activation of Ca2+ currents in locus coeruleus neurons. Biochimica et Biophysica Acta. 2014; 1842; 2569-2578. doi : 10.1016/j.bbadis.2014.07.027
Santin, J.M., Watters, K.C., Putnam, R.W., Hartzler, L.K. Temperature influences neuronal activity and CO2/pH sensitivity of locus coeruleus neurons in the bullfrog, Lithobates catesbeianus. American Journal of Physiology- Regulatory, Integrative, & Comparative. 2013; 305; R1451-R1464. doi: 10.1152/ajpregu.00348.2013
Santin, J.M., Hartzler, L.K. Respiratory signaling of locus coeruleus neurons during hypercapnic acidosis in the bullfrog, Lithobates catesbeianus. Respiratory Physiology & Neurobiology 2013;185, 553-561. doi: 10.1016/j.resp.2012.11.002
For a full list of publications see my Google Scholar profile: Complete list of publications in google scholar