The cremaster muscle has proven to be an excellent tissue for the study of the microcirculation. Its ease of dissection, along with good visibility, provide a tissue that all laboratories can use for the study of the microcirculation. The availability of different hypertension models, along with different species, allows investigators a wide range of preparations to study microcirculatory function. The use of the mouse cremaster in the study of microcirculatory function will undoubtedly lead to the development of new trans-genic models.
Arteriole: A small arteriole, one which, at its distal end, leads to a capillary.
Cremaster: One of the fascia-like muscles suspending and enveloping the testicles and the spermatic cord.
Red cell velocity: The average speed of the blood in blood vessels. The centerline velocity is measured by various optical techniques, and average blood velocity is calculated as Velocityaverage = Velocitycenterljne / 1.6.
Venule: A tiny vein which, at it most proximal end, collects blood from capillaries.
1. Grant, R. T. (1964). Direct observations of skeletal muscle blood vessels (rat cremaster). J. Physiol. 172, 123-137.
2. Majno, G., Gilmore, V., and Leventhal, M. (1967). Atechnique for the microscopic study of blood vessels in living striated muscle (cremaster). Circ. Res. 21, 823-832.
3. Baez, S. (1973) An open cremaster muscle preparation for the study of blood vessels by in vivo microscopy. Microvasc. Res. 5, 384-394. This was the first paper describing the open cremaster preparation. This manuscript is the classic paper that all others reference for the methodology.
4. Sarelius, I. H., Maxwell, L. C., Gray, S. D., and Duling, B. R. (1983). Capillarity and fiber types in the cremaster muscle of rat and hamster.
Am. J. Physiol. 245, H368-H376. The cremaster muscle is used as a model of skeletal muscle. This manuscript provides information about the muscle types in different animal models for the investigator to compare to other animal models.
5. Morff, R. J., and Granger, H. J. (1980). Measurement of blood flow with radioactive microspheres in the intact and surgically exposed rat cremaster muscle. Microvasc. Res. 19, 366-373.
6. Proctor, K. G., and Busija, D. W. (1985). Relationships among arterio-lar, regional, and whole organ blood flow in cremaster muscle. Am. J. Physiol. 249, H34-H41.
7. Klitzman, B., and Duling, B. R. (1979). Microvascular hematocrit and red cell flow in resting and contracting striated muscle. Am. J. Physiol. 237, H481-H490. This manuscript provides information about capillary hematocrit along with muscle blood flow. It is also important because it presents the hypothesis about the role of an unstirred layer in capillaries as a source of the low capillary hematocrit.
8. Meininger, G. A., Harris, P. D., and Joshua, I. G. (1984). Distributions of microvascular pressure in skeletal muscle of one-kidney, one clip, two-kidney, one clip, and deoxycorticosterone- salt hypertensive rats. Hypertension 6, 27-34.
9. Hungerford, J. E., Sessa, W. C., and Segal, S. S. (2000). Vasomotor control in arterioles of the mouse cremaster muscle. FASEB J. 14, 197-207.
10. Hester, R. L., and Duling, B. R. (1988). Red cell velocity during functional hyperemia: Implications for rheology and oxygen transport. Am. J. Physiol. 255, H236-H244.
11. Falcone, J. C., Granger, H. J., and Meininger, G. A. (1993). Enhanced myogenic activation in skeletal muscle arterioles from spontaneously hypertensive rats. Am. J. Physiol. 265, H1847-H1855.
These references were used because they provide normal cardiovascular values for microvessel diameters, red cell velocities, and pressures. The three references by Morph and Granger, Proctor and Busija, and Klitzman and Duling provide normal values for whole tissue blood flows. These references will allow readers to decide the usefulness of this preparation for their experiments.
Dr. Robert Hester is a Professor in the Department of Physiology at the University of Mississippi Medical Center, Jackson, Mississippi. Dr. Hester received his Ph.D. at the University of Mississippi Medical Center and completed a postdoctoral fellowship at the University of Virginia. He has been using the cremaster muscle for the study of functional hyperemia for approximately 20 years.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...