Thermoregulation part I

Originally, I had planned to simply do general research on thermoregulation on the hypothalamus.  As the sumer progressed, however, my research interests narrowed significantly and a new project began to form.  As a result, instead of discussing all of the general aspects of thermoregulation and the hypothalamus, I will discuss my new project in depth.  For my first blog, I will start with a basic overview of thermoregulation and how we study it.

Thermoregulation is essentially the process through which a body maintains a fairly constant internal temperature in a variety of external temperatures.  Thermoregulation is primarily controlled by the hypothalamus.  The hypothalamus receives signals from across the body regarding temperature and takes the necessary steps to either heat or cool the body.  The key to understanding thermoregulation in the hypothalamus is Hammel’s model.  Hammel’s model proposes that thermoregulation is primarily the result of a constant interplay between two types of neurons.  The two types of neurons in Hammel’s model are known as warm-sensitive neurons and temperature-insensitive neurons.  The difference between the two types of neurons is that warm-sensitive neurons increase their firing rates as a result of temperature increases whereas temperature-insensitive  neurons do not.  Hammel proposed that the balance between these two types of neurons is what regulates temperature.  An increase or a decrease in temperature upsets the balance between the two types of neurons (since warm-sensitive cells will respond by changinge their firing rates), resulting in a response that will either cool or heat the body.

To study thermoregulation, we isolate neurons in a hypothalamic tissue slice.  Once we isolate a neuron we can record its firing rate and test how it responds to temperature changes.  After we determine whether the cell is warm-sensitive or temperature-insensitive, we perform a drug treatment to test how the neuron responds to certain chemicals.  The results of this treatment provide insight into the various chemicals and pathways through which the hypothalamus regulates temperature.

After spending the entire summer performing research like this in Dr. Griffin’s lab, I began to wonder if there was another way that we could determine the differences between the two types of neurons.  This question became the basis of my new project, which I will discuss in my next blogs.