Response of Subcutaneous Vessels to Venous Distention

Wiedeman, Mary P.

doi:10.1161/01.res.7.2.238

Cited by 10 publications

(3 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In earlier experiments, intravenous injections of buffered saline in much larger amounts (0.2 ml) did not affect contractile activity in arteriolar vessels, so presumably the injected saline was not responsible for the enhanced activity. 5 Microscopic observation of the cannulated artery from the cannula tip to the area selected for recording activity in a terminal arteriole showed that the infusion of buffered saline caused the oncoming blood to be forced away from the cannula tip, and as pressure continued to rise in the perfusion system, the column of blood was pushed back upstream by the column of saline. The forward flow of arterial blood was diverted into arterial branches proximal to the cannula.…”

Section: Contractile Activity In Terminal Arterioles During Continuoumentioning

confidence: 99%

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

Wiedeman

1966

Circulation Research

Self Cite

View full text Add to dashboard Cite

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...

show abstract

Section: Contractile Activity In Terminal Arterioles During Continuoumentioning

confidence: 99%

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

Wiedeman

1966

Circulation Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…In translucent tissue it is possible to visualize a vein and to estimate its diameter by use of a microscope. This technique has been used to study venous responses in a bat's wing (Wiedeman 1959). An alternative approach which can be applied to non-translucent tissue and to deeper vessels is to inject a radio-opaque dye into a vessel and to estimate its diameter radiographically (Morris et al 1974).…”

Section: Direct Observation Of Cutaneous Veinsmentioning

confidence: 99%

Vascular capacitance: Its control and importance

Hainsworth

Reviews of Physiology, Biochemistry and Pharmacology

101

View full text Add to dashboard Cite

“…In studies of microcirculation involving surgical denervation of blood vessels in bat wings (8)(9)(10), microscopic observation of the vessels following denervation revealed that (1) major arterial vessels increased markedly in diameter following denervation; (2) small arterial vessels such as arterioles and terminal arterioles did not show such an increase; 84 WIEDEMAN (3) major arterial vessels lost their ability to contract in circumstances which had previously provoked active contraction; and (4) small arterial vessels continued to contract spontaneously after denervation. It appeared that only the large arterial vessels were rendered inactive by denervation, and it was assumed that only they were predominantly under nervous control.…”

mentioning

confidence: 99%

Blood Flow through Terminal Arterial Vessels after Denervation of the Bat Wing

Wiedeman

1968

Circulation Research

Self Cite

View full text Add to dashboard Cite

Previous studies of microcirculation in the denervated wing of the unanesthetized bat showed that major arterial vessels increased markedly in diameter and lost their ability to contract spontaneously. Arteriolar vessels did not show such an increase in diameter, and furthermore their spontaneous contractile activity increased. These observations led to the idea that regulation of blood flow and blood pressure might be continued to some degree in the absence of central nervous control through enhanced activity of arteriolar vessels which just precede the capillary nets.Therefore a thorough study by direct microscopic observation of the behavior of arterial vessels in the following surgical and pharmacological denervation was made. The data support the hypothesis that loss of tone and loss of contractile activity in the large arterial vessels following denervation produce an increase of tone and activity in the smaller, more distally located vessels, thereby causing a redistribution of the site of regulation of flow through capillary nets. The largest arterial vessels showed an increase in average diameter of 383! after surgical denervation, while the terminal arterioles showed a decrease in average diameter of 24%. Neither phenoxybenzamine (Dibenzyline) nor pentolinium (Ansolysen) were as effective as surgical denervation in producing relaxation of the large arterial vessels. Neither drug inhibited spontaneous contractile activity of the terminal vessels.

show abstract

Response of Subcutaneous Vessels to Venous Distention

Abstract: Direct observations of circulation in small vessels of the bat wing indicated that increased resistance to arterial flow could be produced by venous distention without active vasoconstriction.

Cited by 10 publications

References 12 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

Vascular capacitance: Its control and importance

Blood Flow through Terminal Arterial Vessels after Denervation of the Bat Wing

Contact Info

Product

Resources

About