Article Title: Appearance of Adenosine in Venous Blood From The Contracting Gracilis Muscle and its Role in Vasodilatation in the Dog
Authors: H. J. Ballard, D. Cotterrell and F. Karim
Journal: The Journal of Physiology
Key Points leading to why this study was conducted
- The relationship between adenosine and exercise hyperemia is unclear.
- Some studies showed adenosine level increase in muscles during constant blood flow and ischemic contraction. However, previous studies had some errors in regards to measurements and they did not use sensitive measurement tools such as the high performance liquid chromatography (h.l.p.c.).
Purpose or hypothesis
- The study had two purposes. First, to determine whether adenosine level would increase…show more content… - The design of the study is experimental and quantitative.
- The first part of the experiment was that dogs were anaesthetized, and the femoral artery and vein were isolated from the circulation and connected to a perfusion circuit.
- This perfusion circuit connected proximal femoral artery with its distal end through a roller pump, and connected by the same way the femoral vein with the external jugular vein.
- The tendon of the gracilis muscles was attached to a force transducer.
- The experiment started with denervation of the muscle and maintaining constant blood through the roller pump.
- Then, the muscle was electrically stimulated for 20-21 minutes (five dogs), 10 minutes (four dogs), and 20 minutes (one dog).
- The blood samples were collected at predetermined sets of intervals during the contractions and also for 10 minutes after the contractions.
- After that, adenosine was administered to the muscle for four minutes until the perfusion pressure was stable and then venous blood samples were collected.
- The procedure was repeated multiple times.
- By the end of the experiments, gracilis muscle was taken out, and the dogs were killed.…show more content… - Venous adenosine was significantly higher than arterial adenosine during contractions.
- Infusion of adenosine led to vasodilation and decrease in arterial perfusion pressure (6 %).
- Even though adenosine has shown to increase blood flow, there are other factors help to initiate and maintain vasodilatation during and after contractions.
Take Home Message
- The role of adenosine in increasing blood flow to skeletal muscle was not clear. However, this studies showed not only that adenosine contributed to exercise hyperemia but also showed that adenosine was not the most important factor and there are other factors responsible for initiating and maintaining vasodilation besides adenosine.
- H.p.l.c. was used to analyze adenosine concentration, which is a sensitive technique that was not used in previous studies.
- There were a lot of details in the methods that clearly explain how experiment was done.
- The researchers did a great job controlling variables that could affect the results, like body temperature, blood gasses, systemic pH, blood flow rate and so