60,000 Americans die each year from uncontrolled bleeding and bleeding is responsible for 35% of pre-hospital deaths. New research in mice shows that through electrical stimulation of the vagus nerve, it is possible to prohibit bleeding. But, how does bleeding stop? Bleeding stops in a process called hemostasis.Figure 16.4.4 : Blood ClotAn important part of this process is the activation of platelets to form a platelet plug to prevent further blood flow. Platelets activate when a blood vessel is injured and the vessel wall constricts to reduce blood flow. Platelets are involved in the The Neural Tourniquet that becomes activated using vagus nerve stimulation. The Neural Tourniquet shows the vagus nerve and its connection to the spleen via the celiac ganglion. Stimulation of the vagus nerve harnesses the acetylcholine secreting Choline Acetyltransferase (CHaT+) T-cells to stimulate calcium uptake and alpha granule secretion via alpha 7 nicotinic acetylcholine receptors found on platelets and therefore activates platelets and accelerate clotting. This made researches believe that the splenic CHaT+ T-cells secrete acetylcholine to regulate the function of platelets. How can this be proven?

One way in which this was proven was by using immunohistochemistry to explore the interactions between the CHaT+ T-cells and platelets. Immunohistochemistry is a technique in which antibodies are used to label cell structures so we can take close up photos of cells. The zoomed out photo below is a photo of the spleen. The purple is the white pulp where lymphocytes are located and the green is the red pulp where platelets and all other circulating blood cells can be found. The zoomed in photo below shows the interactions between CHaT+ T-cells (pink with purple halo) and platelets (green) directly touching proving that the stimulation of the vagus nerve activates platelets.

The next step for this research is beginning a clinical trial to see if these interactions can exist in humans as well. Procedures will be repeated in humans. To optimize the assays for the clinical trial, flow cytometry (a technique that will allow one to study single cells using fluidics, optics, and electronics) will be used to determine which anticoagulants work best to keep the platelets from activating without an agonist.

In AP Bio, we learned about that the Rough ER is directly connected to the cell nucleus. The Rough ER is similar to the celiac ganglion in which the celiac ganglion is directly connected to the vagus nerve and allows it to connect to the spleen. The Rough ER allows the cell to function by producing proteins and the celiac ganglion allows the vagus nerve to connect to the spleen via the parasympathetics nervous system showing that their connection to other parts of the cell or body is what makes them essential.

(I took these photos at the Feinstein Institute this summer!)