Interrelations between contracting striated muscle and precapillary microvessels

Abstract

Arterioles and capillaries in the hamster cremaster muscle were observed during electrical stimulation of striated muscle fibers in order to characterize the microcirculatory basis of functional hyperemia. When contraction was restricted to single muscle fibers, responses were variable and frequently transient. Stimulation of either small bundles of muscle fibers or the entire cremaster muscle resulted in reproducible responses typified by: 1) a latency period, 2) an early, often transient phase of dilation, and 3) a second, slower phase of dilation. The latency varied inversely with contraction frequency, and the magnitude of the dilation varied directly with contraction frequency over the range 1--8/s. With stimulation of single fibers and small groups of fibers, arteriolar vasodilation was highly localized to regions of the arterioles that were in close apposition to the stimulated fibers. The number of capillaries with red blood cell flow increased during contraction, and the increase was graded with contraction frequency. The changes observed suggest that the vascular response during functional hyperemia is a two-part process and that the control processes are influenced by contraction frequency.

Striated Perineal Muscles: Location of Autonomic, Sensory, and Somatic Neurons Projecting to the Male Pig Bulbospongiosus Muscle

“…In fact, during skeletal muscle contraction it is possible to observe a local functional vasodilation, rapidly followed by a sympathetic vasoconstriction (Thomas and Segal, 2004). Initially the rhythmic skeletal muscle contractions augment capillary perfusion (Sweeney and Sarelius, 1989) and promote the extraction of oxygen and nutrients from the blood (functional vasodilation) (Gorczynski et al, 1978;Marshall and Tandon, 1984;Van Teeffelen and Segal, 2003). Subsequently the blood flow is restricted by the autonomic nervous system to increase and preserve the local pressure (Van Teeffelen and Segal, 2003).…”

Sensory and Autonomic Neurons Project Both to the Smooth Retractor Penis and to the Striated Bulbospongiosus Muscles. Neurochemical Features of the Sympathetic Subset

“…In fact, during the contraction of a muscle it is possible to observe a local functional vasodilatation, quickly followed by a sympathetic vasoconstriction (Thomas and Segal, 2004). Initially, the contraction of muscle augment capillary perfusion (Sweeney and Sarelius, 1989) promote the extraction of oxygen and nutrients from the blood (functional vasodilation) (Gorczynski et al, 1978;Marshal and Tandon, 1984;Van Teeffelen and Segal, 2003). Afterwards the blood flow is restricted by the autonomic nervous system to increase and preserve the local pressure (Van Teeffelen and Segal, 2003).…”

Appearance of adenosine in venous blood from the contracting gracilis muscle and its role in vasodilatation in the dog.

“…It is likely that complete equilibration does occur, first because pre-capillary sphincters are absent and arterio-venous shunts are very scarce in skeletal muscles (Erikson & Myrhage, 1972;Gorczynski, Klitzman & Duling, 1978) so that all infused adenosine must pass through the capillaries, and secondly because adenosine is a small, highly mobile molecule and the diffusion distance is very short. Therefore, any underestimation of the effects of adenosine due to this factor would be small.…”