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Lofstroni, B., B. Pernow and J. Wahren. Vasodilating action of substance P in the human forearm. Acta physiol. scand. 1965. 63. 31 1-324. -The vasodilator activity of substance P in the human forearm has been studied using venous occlusion plethysmography. The effects have been compared to those of bradykinin. The compounds were given as single injections or infusions into the brachial artery or the antecubital vein. 1.a. administration caused a significant increase in skin and muscle blood flow in doses of more than 0.5 units of substance P per min. The oxygen saturation of blood from both deep and superficial veins of the forearm increased. These effects were not influenced bv atropine, antihistaminics or guanethidine. Stellate ganglion block increased the resting blood flow as well as the vasodilating action of both polypeptides. I.v. infusion c f substance P and bradykinin also caused an increase in forearm blood flow coincident with tachycardia and flushing of the face and the neck. During substance P infusion the increase in forearm blood flow and flushing appeared simultaneously, while bradykinin caused an increase in the forearm blood flow only in doses which were almost intolerable for the subjects due to severe pulsations and flushing of the skin of the head and the neck. T h e ratios between equieffective doses of substance P and bradykinin on the forearm blood flow were about 1 : 10 at i.a. infusion and about 1 : 200 at i.v. infusion.Already in the first publication on substance P (Euler and Gaddum 1931) it was suggested that the hypotensive effect obtained after i. v. administration of the substance was due to a peripheral vasodilatation. Holton and Holton (1952) found an increased blood flow through the rabbit ear following i. v. injection ofsubstance P. During studies on the effect of substance P on the intestinal motility (Liljedahl, Mattsson and Pernow 1958) and the central hemodynamics in man (Duntr and Pernow 1960) it was observed that i. v. infusion of the substance caused an intensive flushing in the face and neck, obviously due to cutaneous vasodilatation. This paper deals with the effects of substance P, following i. a. and i. v. administration, on skin and muscle blood flow in the human forearm. The effects of substance P 31 1 312 BERTIL LOFSTROM ET AL. Forearm blood flow (ml/lOO ml?issuc/rnln)

SUMMARY Mepivacaine and lidocaine were infused intravenously and into the brachial artery in healthy human subjects. The effects on arterial blood pressure, forearm blood flow, forearm vascular resistance and venous tone were studied. Intravenous infusion of mepivacaine at a rate of 0.25 mg per kg body weight per min during 20 minutes increased the mean arterial blood pressure, forearm blood flow and venous tone. Blockade of the sympathetic nerves to the arm abolished die effect on blood flow, while the increase in blood pressure and venous tone persisted. Intra‐arterial infusions of 0.5‐6 mg per min of mepivacaine increased the venous tone and decreased the forearm blood flow. The mean arterial blood pressure was unchanged, while the calculated forearm vascular resistance increased. Following sympadietic blockade, the effect on forearm vascular resistance and blood flow was almost completely eliminated, while the increase in venous tone persisted. Intra‐arterial infusion of 1‐3 mg per min of lidocaine increased the venous tone, but did not significantly influence die arterial blood pressure of forearm blood flow. ZUSAMMENFASSUNG Mepivacain und Lidocain wurden gesunden Versuchspersonen sowohl intravenos als auch in die Armaterie infundiert. Dabei wurde die Wirkung auf den arteriellen Blutdruck, die Durchblutung des Unterarmes, der Gefass‐widerstand des Unterarmes und auch der Venentonus untersucht. Die intra venose Infusion von Mepivacain mit einer Geschwindigkeit von 0,25 mg pro kg Korpergewicht und Minute wahrend 10 Minuten erhohte den mittleren arteriellen Blutdruck, die Durchblutung des Unterarmes und den Venentonus. Blockade der sympadiischen Nerven des Armes loschte die Wirkung auf die Durchblutung aus, wahrend der erhohte Blutdruck und Venentonus bestehen blieben. Intraarterielle Infusion von Mepivacain 0,5‐0,6 mg pro Minute er‐hohten den Venentonus und verminderten die Durchstromung des Unterarmes. Der mittlere arterielle Blutdruck blieb unverandert, wahrend der er‐rechnete Gefasswiderstand des Unterarmes anstieg. Nach Sympathikusblockade verschwand die Wirkung auf den Gefasswiderstand des Unterarmes und auf die Durchblutung nahezu vollstandig, wahrend der erhohte Venentonus bestehen blieb. Die intraarterielle Infusion von Lidocain 1‐3 mg/Minute erhohte wohl den Venentonus, hatte aber keinen signifikanten Einfluss auf den arteriellen Blutdruck und die Durchblutung des Unterarmes.

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Chest wall mechanics were studied in six healthy volunteers before and during anesthesia prior to surgery. The intratracheal, esophageal, and intragastric pressures were measured concurrently. Gas flow was measured by pneumotachography and gas volume was obtained from it by electrical integration. Rib cage and abdomen movements were registered with magnetometers, these being calibrated by "isovolume" maneuvers. During spontaneous breathing in the conscious state, rib cage volume displacement corresponded to 40% of the tidal volume. During anesthesia and artificial ventilation, this rose to 72% of the tidal volume. The relative contributions of rib cage and abdomen displacements were not influenced by a change in tidal volume. Compliance was higher with a larger tidal volume, a finding which could be due to a curved pressure-volume relationship of the overall chest wall.