Abstract
The responses of four veins in the dog, the accessory cephalic, lateral saphenous, external iliac and the splenic, to several vasoconstrictor stimuli were observed. The agents used were acetylcholine, norepinephrine and sympathetic nerve stimulation. Only in two veins, the accessory cephalic and lateral saphenous, could vasoconstriction be induced by these treatments. It was observed that the responses were of a localized nature. Nicotine did not produce venoconstriction in any of the preparations. Histologic examination of these regions showed an area that contained valves and was richly invested with smooth muscle. Valves were present also in nonreactive veins; however, these veins lacked any appreciable amount of smooth muscle fibers in the tunica media. It would appear, then, that venoconstriction in these veins involves localized areas containing valves and rich in smooth muscle.
Footnotes
- Received April 26, 1966.
- Accepted June 23, 1966.
- © 1966 by The Williams & Wilkins Co.
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