Blood Circulation in the Subcutaneous Tissue of the Living Bat's Wing

Nicoll, Paul A.; Webb, Richard L.

doi:10.1111/j.1749-6632.1946.tb31698.x

Cited by 101 publications

(12 citation statements)

References 10 publications

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“…6 Nicoll and Webb 6 described a powerful contraction of small arterioles or venules resulting from a sudden increase in internal pressure. Nicoll 7 observed constriction of arteriolar vessels at their origin during resumption of blood flow after flow had been artificially blocked.…”

Section: Discussionmentioning

confidence: 99%

Contractile Activity of Arterioles in the Bat Wing during Intraluminal Pressure Changes

Wiedeman

1966

Circulation Research

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Spontaneous contractile activity in the smooth muscle cells that invest arteriolar vessels is widely variable. Arteriolar branches originating from the same parent vessel contract independently of one another with no similarity in frequency or duration of individual contractions.Direct microscopic observations were made of these vessels in the wing of unanesthetized bats before and after surgical denervation or nerve block by procaine. A major artery of the wing was cannulated and buffered saline was perfused in retrograde fashion to produce periods of increased intra-arterial pressure. Elevation of intraluminal pressure led to enhanced contractile activity both before and after denervation of the vessels. It is concluded that these vessels respond by contraction to increased pressure and that the response is not dependent on nervous activity. ADDITIONAL KEY WORDSspontaneous arteriolar contractions intraluminal pressure denervation myogenic response autoregulation capillary blood flow• The fact that vascular smooth muscle has the inherent property of automaticity and that its contractile activity can be enhanced by stretching occupies an important place in present day discussions of autoregulation of blood flow. 1 -8 The contraction of arterial vessels in response to distention is a basis for the myogenic theory of autoregulation. According to Folkow, 2 flow resistance can be increased to a considerable extent over a period of time by increasing the frequency and duration of contraction of precapillary sphincters when intraluminal pressure is elevated.It seemed possible to determine directly whether precapillary vessels constrict more frequently and the contractions continue for a greater period of time when intraluminal pressure is increased within physiological limits by utilizing a technique of microscopic observation of the small blood vessels while varying intraluminal pressure. If they do, this would strengthen Folkow's contention that Supported in part by research Grant HE02280-10 from the National Heart Institute, U. S. Public Health Service.Accepted for publication March 24, 1966. basal vascular tone depends on this myogenic property and that it can produce autoregulation. ' 2Microscopic observation of vessels in the wing of the bat seemed ideal for such a study because neither anesthesia nor surgery are necessary and observations can be made at high powers of magnification without disturbing the normal circulation. Thus, interference which might obliterate or reduce autoregulation of blood flow is minimal. Also, direct observation of the vessels make it possible to ascertain when the perfusion pressure reaches a level that exceeds physiological limits and overdistends the vessel. MethodCommon brown bats (Myotis) were used. An unanesthetized bat was prepared for observation by placing it in a suitable holder and extending one wing over a glass plate. The wing was held in place by spring clips and a drop or two of mineral oil was put between the wing and the glass for visual clarity. To furthe...

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Section: Discussionmentioning

confidence: 99%

Contractile Activity of Arterioles in the Bat Wing during Intraluminal Pressure Changes

Wiedeman

1966

Circulation Research

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“…DISCUSSION-While the change in arterial flow observed here in response to venous distention is similar to results obtained with indirect methods, the explanation differs. The observations reported RESPONSE OF SUBCUTANEOUS VESSELS TO VENOUS DISTENT ION [2][3][4][5][6][7][8][9][10][11] here argue against a venoarteriolar reflex. The end result of elevated venous pressure in these subcutaneous vessels was an increased resistance to arterial inflow, but the resistance was not produced by any obvious or observed vasoeonstriction in small vessels, either arterial or venous.…”

Section: Response To Increased Venous Pressure With Saline Infused Inmentioning

confidence: 91%

“…7 The unanesthetized animal is slipped into a holder that allows the wings, lightly held by spring clips, to be extended over a glass plate. This permits normal circulation with active vasomotion prominent and rhythmical in the veins and irregular in arterioles and precapillary sphincters.…”

Section: Methodsmentioning

confidence: 99%

Response of Subcutaneous Vessels to Venous Distention

Wiedeman

1959

Circulation Research

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“…The vascular pattern in rat subcutaneous tissue is the "simple network pattern" [54] seen in the bat wing [55] and hamster cheek pouch [56] (Fig. 9a).…”

Section: Connection Relations Between Tumor-feeding Vessels and Host mentioning

confidence: 98%

Starvation tactics for solid tumors: tumor blood flow interruption via a combretastatin derivative (Cderiv), and its microcirculation mechanism

Hori

2011

Cancer Metastasis Rev

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Combretastatin can prevent the supply of nutrients to cancer cells by selectively interrupting tumor blood flow (TBF). Therefore, combretastatin may serve as a new anticancer drug that utilizes starvation tactics to attack solid tumors. Among combretastatin compounds, combretastatin A-4 and a combretastatin A-4 derivative (Cderiv) are now in phase III clinical trials. These two combretastatin compounds have similar chemical structures and provide marked TBF interruption. However, their mechanisms of action are reportedly quite different and remain controversial. Precise mechanisms of action of these agents must be elucidated so as to develop safe clinical treatments and wider clinical applications. By using various kinds of rodent tumors, we showed that Cderiv produced potent interruption of TBF in all primary tumors and metastatic foci, without exception, and had beneficial therapeutic effects including significantly improved survival. Cderiv caused host arterioles to constrict. However, a tumor vascular bed scarcely reacted to a direct topical application of Cderiv. In addition, the fact that Cderiv did not have cytotoxic drug-like accumulated toxicity usually caused by repeated administration means that inhibition of tubulin polymerization by Cderiv may not occur to a great degree in vivo. Therefore, at least for Cderiv, our studies demonstrated that TBF interruption was mainly caused indirectly, via enhancement of vascular resistance of host arterioles, rather than being caused by a direct effect of Cderiv on tumor vessels. In this review, I describe cancer therapy that utilizes such TBF interruption, which leads to Cderiv-induced necrosis, and discuss details of its microcirculation mechanism.

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Blood Circulation in the Subcutaneous Tissue of the Living Bat's Wing

Cited by 101 publications

References 10 publications

Contractile Activity of Arterioles in the Bat Wing during Intraluminal Pressure Changes

Contractile Activity of Arterioles in the Bat Wing during Intraluminal Pressure Changes

Response of Subcutaneous Vessels to Venous Distention

Starvation tactics for solid tumors: tumor blood flow interruption via a combretastatin derivative (Cderiv), and its microcirculation mechanism

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