A quantitative study of the response to acetylcholine and histamine of the blood vessels of the human hand and forearm

Abstract

Many investigators have injected acetylcholine and histamine into man both intra-arterially and intravenously. The effects of intra-arterial injection of acetylcholine on the circulation in the legs were studied by Carmichael & Fraser (1933) who observed skin colour, and by Ellis & Weiss (1932) who measured skin temperature and arterio-venous oxygen differences. We have been unable, however, to find detailed quantitative measurements of their effects on the vessels. Since such observations were required for another purpose we have made them, and this paper describes the results. METHODSObservations have been made on twenty-six men and three women between the ages of 19 and 34. All were in good health, and none suffered from peripheral vascular disease. They arrived at the laboratory at least 1 hr before observations started and were recumbent during, and for half an hour before, the observations. They wore normal indoor clothing, and the trunk and legs and as much as possible of the arms were wrapped in blankets. The laboratory temperature was 20-23' C.Blood flow The blood flow through the hands and forearms was measured every 15 sec, or more frequently, by venous occlusion plethysmography. In most experiments the plethysmographs were filled with stirred water at 32°C for the hand and at 340 C for the forearm. They were fitted with loose gloves for the hands or loose sleeves for the forearms. In some experiments, in which it was desired to measure simultaneously the hand and forearm flow on the same side, a light celluloid air-filled plethysmograph was used on the forearm.The venous occlusion cuffs, at the wrist for the hand, and above the elbow (proximal to the needle in the brachial artery) for the forearm, were, unless otherwise stated, inflated to 70 mm Hg during the periods of collection. A wrist cuff was inflated to 200 mm Hg for 1 min before, and during, observations of forearm blood flow. When, however, the hand and forearm blood flows

The response to vasodilator substances of the blood vessels in fingers immersed in cold water

“…Intra-arterial injections of 45-75 jug histamine (ten experiments) or 5-10 mg acetylcholine (ten experiments) during the 3rd min following the insertion of the fingers into the cold, that is, when the cold vasoconstriction was well established, did not cause a premature vasodilatation (Fig. 2a, b), although smaller doses of histamine always, and of acetylcholine usually, cause a large increase in hand blood flow at 32°C (Duff, Greenfield, Shepherd & Thompson, 1953). The complete or almost complete arrest of the circulation during the first few minutes of immersion in the cold water (Greenfield & Shepherd, 1950) must, however, restrict the amount of drug reaching the finger.…”

A quantitative study of the response to adenosine triphosphate of the blood vessels of the human hand and forearm

“…ATP in suitable doses can cause just as large an increase in forearm and hand blood flow as does acetylcholine or histamine (Fig. 6) without the uncomfortable local bursting sensation which sometimes occurs with the former, or the facial flushing and headache associated with the latter (Duff et al 1953). …”

“…The possibility of an unequal distribution of a drug solution throughout the limb following intra-arterial infusions (Duff et al 1953) must be kept in mind when comparing the local circulatory effects of the same or different drugs on different subjects. In three subjects in the present series, the distribution was so localized that there was practically no increase in hand blood flow or in the flow through the segment of forearm inside the plethysmograph.…”

The Action of 5‐hydroxytryptamine on the Blood Vessels of the Human Hand and Forearm

“…Feldberg and Smith (1953) have shown that large doses of 5-HT cause release of histamine from the perfused skin flap of the cat, accompanied by vasoconstriction and oedema formation. Although histamine, in a wide range of doses, injected intraarterially into the forearm or hand in man, always causes dilatation of the resistance vessels and an increase in flow (Duff, Greenfield, Shepherd, and Thompson, 1953), it is conceivable that the direct constrictor action of 5-HT on the resistance vessels might counteract the dilator action of histamine on these vessels while leaving unopposed its action on the capillaries. On the other hand, Reid (1952) demonstrated that the flush of the skin caused by intradermal injection of 5-HT was not accompanied by itching or a weal, and preliminary exp:riments in this department indicate that there is no diminution of the flush following intra-arterial injection of antihistamine.…”