This experimental method was obtained from the official website of Chongqing Medical University
Operation method
Morphologic experiments on the response of venous endothelial cells to histamine
Principle
It can be witnessed through experiments that when the human body comes into contact with allergens, the immune response process of macrophages-B lymphocytes-plasma cells produces IGE, and mast cells release histamine, which causes vasodilatation and permeability enhancement, which is known as the "rapid-onset transient reaction". This causes vasodilatation and increased permeability, which is called a "rapid-onset transient reaction", and red, swollen patches on the skin surface, which is called an "allergic reaction". Using the mesentery of toads or frogs to make live specimens, the phenomenon of histamine-induced changes in blood vessels can be observed, with changes in the diameter of the vasodilatation tubes, a widening of the axial flow (blood cell flow), and a loss of the boundary between axial and marginal flow (plasma flow), among other morphologic phenomena. Histamine (histamine) is a vasoactive amine released by mast cell degranulation initiated by the production of IGE by the immune system (B-lymphocytes-plasma cells). The primary effects of histamine cause dilation of microarterioles and increased permeability of microveins. When histamine is given, the sphincters of the microarterioles dilate and blood flow is accelerated. In turn, histamine binds to the receptor (H 1) of the endothelial cells of the microveins, and the endothelial cells immediately undergo contraction, leading to the formation of an endothelial cell gap. This process lasts 15-30 minutes and can be referred to as the "rapid onset transient response". This reaction generally occurs in veins with a diameter of 20-60 mm.
Materials and Instruments
Histamine Move Animal: Toad or Frog Common Problems Add 1-2 drops of 0.2% histamine to the mesentery, and continue to observe for several minutes, vasodilatation can be seen, blood flow slows down gradually, the boundary between axial and marginal flow disappears, and there is a clear back and forth oscillation of blood flow, with leukocytes flowing into the plasma layer and adhering to the vascular wall, i.e., the "wall-attached phenomenon". For more product details, please visit Aladdin Scientific website.
Instrument trays Probes Scissors Tweezers Large lancets Cotton balls Microscope
1. Destruction of frog spinal cord with a probe
2. In the supine position, cut the abdominal wall along the lateral abdominal wall, the incision is about 1.0 cm long.
3. Use forceps to gently pull out the small intestinal collaterals, unfold the mesentery connected to the collaterals on the instrument tray, and cut down the mesentery with the collaterals for about 1-1.5 cm. (Special attention should be paid to gently pulling the collaterals, and avoid pulling them too tightly or tearing the mesentery to prevent affecting the blood circulation).
4. Under low magnification, select a small vein field of view, observe the caliber of the blood vessels of the micro-vein, the blood flow rate and the blood flow condition, and distinguish the axial flow (blood cell layer) from the marginal flow (plasma layer). Add several drops of 0.2% histamine to the mesentery and continue observation for several minutes.