Studies on the Slow Contraction of Smooth Muscle Produced by Human Plasma

Abstract

The slow contraction of smooth muscle produced by human plasma becomes less potent after storage of the plasma for six months at room temperature and after processing of the plasma with kaolin. These observations fall into line with the fact that 40% of the initial smooth-muscle-contracting activity of the plasma can be accounted for in the deposit which is formed during the six-months period of storage, and also with the fact that the recovery of G acid from human plasma treated with kaolin is about 50% of the yield which is obtained from the same plasma before kaolin treatment.Plasma is known to produce a quick contraction of the isolated guinea-pig ileum which is due to the presence of histamine or 5-hydroxytryptamine. It has recently been shown that after dialysis, which removes these agents, certain plasmas produce a delayed (at least 15 sec), slowly developing contraction of the ileum which is probably due to the formation of kallidin (or bradykinin) due to activation, by dilution, of an enzyme in plasma which releases it from a precursor which is also present (Schachter, 1956).When larger volumes of human plasma are tested, evidence of another agent producing a delayed contraction appears. In this case there is a delay of only 4 to 10 sec after the addition of plasma to the isolated ileum, which then shortens fairly quickly, the response reaching a maximum within 30 sec. Recently, Gabr (1956) described the isolation from human plasma of a fatty acid which has a similar effect on the guinea-pig intestine. The present paper deals with the slow contraction produced by pooled plasma treated with kaolin (Maizels, 1944) and by pooled plasma stored at room temperature over a period of six months (Allen, Sykes, Enerson, Moulder, Elghammer, Grossman, McKeen & Galluzzi, 1950). The effect of pooled plasma on this contraction has also been studied.In the method in which plasma is treated with kaolin, fibrinogen is removed from citrated plasma by adsorption, so that a fibrinogen-free plasma results which will not clot on filtration. Transfusion with this material has been particularly free from reactions, which suggests that kaolin may remove toxic substances.According to Allen et al. (1950), pooled plasma stored in the liquid state without preservatives at room temperature for six months or longer before use produced no cases of homologous serum jaundice on transfusion when this was the only product administered. The virus of homologous serum jaundice in pooled plasma, which

Possible Role of Lecithin in the Development of the Slow Muscle Contracting Activity of Human Plasma

“…effect produced by lecithin on incubation with human plasma The slow contraction of smooth muscle produced by human plasma becomes less potent after treatment with kaolin according to the method devised by Maizels (1944) for the clarification of the plasma. The recovery of G acid from such kaolin treated plasma is about 50% of the yield which is obtained from the same plasma before kaolin treatment (Gabr, 1961). Parallel experiments showed that the S.M.C.…”

“…Sterility control, treatment with kaolin, and effect of calcium ions Sterility control (Gabr, 1961) was carried out on all experiments before and after incubation. Aliquots of normal plasma and lecithin-plasma were treated with kaolin (Maizels, 1944).…”

“…The determinations on the isolated guinea-pig ileum were made, as previously described (Gabr, 1961), using a chamber of 55 ml. capacity filled with oxygenated Tyrode solution, the standard of reference being a specimen of the same plasma pool which had been incubated for the same period of time as the lecithin-plasma incubate.…”

“…effect produced by human plasma is best observed after dialysis, since dialysis removes the quick contracting agents. Gabr & Aly (1959) and Gabr (1961) observed that the S.M.C. effect produced by human plasma becomes less potent after storage for six months at room temperature.…”

Arachidonic acid is responsible for the smooth muscle-contracting activity of G-acid.

“…In 1956, Gabr reported the isolation of a substance from human blood plasma which slowly contracted isolated guinea pig jejunum or ileum and was thought to cause certain adverse plasma transfusion reactions (1,2). He named this substance, associated with the globulin fraction, G-acid, and deduced that it was a fatty acid containing 18 carbons and one double bond.…”