## Applied Mathematics Colloquium: Dr. Patrick Fletcher

#### NIH/NIDDK

Friday, December 8, 2017 · 2 PM - 3 PM

**Title:**Modeling spontaneous and stimulated electrical activity in pituitary corticotroph cells

**Speaker:**Patrick Fletcher, NIH/NIDDK

**Abstract:**The electrical activity and calcium dynamics of pituitary corticotroph cells has been recently demonstrated to be strikingly diverse, both spontaneously and in response to the agonists corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP). These cells typically fire tall, sharp action potentials when spontaneously active, but a variety of other spontaneous patterns have also been reported, including various modes of bursting. We demonstrate this diversity with electrophysiological measurements and use mathematical modeling to investigate its possible sources. The model is explored using fast-slow analysis and GPU-accelerated numerical simulations. In the model, variation in as few as two parameters can give rise to many of the types of patterns observed in electrophysiological recordings. We compare the known mechanisms for CRH, AVP, and glucocorticoid actions, showing how the context of the cell's ionic conductances dictates the effects of agonists.