High-dose intravenous metoprolol was well tolerated in patients with suspected AMI. There was a more rapid and almost complete pain relief in patients without signs of transmural ischaemia compared with the patients with ECG signs of transmural AMI at arrival. In the later group of patients, plasma clearance of metoprolol was significantly reduced.

Objectives. To compare the analgesic effect of metoprolol and morphine in patients with chest pain due to suspected or definite acute myocardial infarction after initial treatment with intravenous metoprolol.Design. All patients, regardless of age, admitted to the coronary care unit at Uddevalla Central Hospital due to suspected acute myocardial infarction were evaluated for inclusion in the MEMO study (metoprolol-morphine). The effects on chest pain and sideeffects of the two treatments were followed during 24 h. Pain was assessed by a numerical rating scale. Results.A total of 265 patients were randomized in this prospective double-blind study and 59% developed a confirmed acute myocardial infarction. In both treatment groups, there were rapid reductions of pain intensity. However, in the patient group treated with morphine, there was a more pronounced pain relief during the first 80 min after start of double-blind treatment. The side-effects were few and were those expected from each therapeutic regimen. During the first 24 h, nausea requiring anti-emetics was more common in the morphine-treated patients. Conclusion.In suspected acute myocardial infarction, if chest pain persists after intravenous betaadrenergic blockade treatment, standard doses of an opioid analgesic such as morphine will offer better pain relief than increased dosages of metoprolol.

Summary. Dale'S original definition of the different actions of ac. ch. stated that muscarinelike actions are those which are abolished by atropine, while the nicotinelike actions are not antagonized. Later experiments show that both kinds of actions are antagonized by atropine, even if several exceptions from this rule are described There is, however, a quantitative difference between muscarinelike and nicotinelike actions with regard to the atropine antagonism. As a rule, muscarinelike actions are inhibited by smaller concentrations, while nicotinelike actions require higher concentrations of atropine. This quantitative difference is by some authors looked upon as a criterion of a fundamental distinction between the two kinds of action. The nicotinelike actions require, however, not only larger amounts of atropine, but also large amounts of ac. ch. It seems possible that those properties of an organ which make large amounts of ac. ch. necessary also make it necessary to use large amounts of atropine before the antagonism can be demonstrated. It is shown in the present paper that there is a constant ratio between the amounts of atropine which are necessary to provoke a certain effect on various organs of frog and the amount of atropine which is necessary for diminishing this effect to a certain degree. Thus, the quantitative differences between the two kinds of action with regard to the atropine antagonism do not seem to constitute any real distinction. Striped muscles of frog must be exposed to atropine during 50 to 60 minutes, before the atropine exerts its full antagonistic power. Is has been shown previously that atropine antagonizes the effect of ac. ch. on striped muscles, when these are suspended in a bath, while the effect of intraarterially injected ac. ch. is not abolished. In the latter case too small amounts of atropine seem to have been used. In the present paper is shown that atropine prevents the “quick contractions” of skeletal muscles of frog or rabbit, provoked by intraarterial injections of ac. ch. Those amounts of atropine which abolish the “quick contractions” do not have any influence on the excitability of the muscles through their nerves. If, however, the muscles are suspended in very strong concentrations of atropine they lose at first their indirect excitability and then also their direct excitability. Several reasons—inter alia the effect of d and l‐hyoscyamine—show that this so‐called curare‐action” of atropine is not of the same nature as the ac. ch.‐antagonizing effects of atropine. Thus, while the effects of added ac. ch. is abolished, atropine exerts no action on the indirect excitability which can be explained as an antagonizing of ac. ch. It is emphasized that the theory of humoral transmission at present offers no acceptable explanation of this discrepancy.

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(With I figure in the text.) 'The digitalis substances exert a carclio-inhibitory vagal effect, causing bradycardia. Sometimes, however, a negative chronotropic digitalis effect, though usually moderate, may also be observed aftcr division of the vagal nerves and after isolation of the heart.In experiments on dogs G r e m e l s ( 1 9 3 5 ) has shown, that strophantin sensitizes the heart muscle to vagal stimulation. Recently A b d o n and N i e l s e n (1937) found, that the cardio-inhibitory vagal effect caused by the digitalis substances presumeably solely is due to this peripheral effect, the bradycardia being due to a sensitization of the myocardium to the normal vagal tone. With the demonstration by L ocwi of acetylcholin as the vagus substance the explanation appears reasonable, that the effect on the myocardium rcpreeents a sensitization of the latter towards acetylcholin.The chronotropic digitalis effect after vagotomy and on the isolated heart may be similarly explained, as these hearts must be assumed to contain acetylcholin.In the present paper the validity of this hypothesis has becil investigated by experiments on isolated hearts of frogs, rabbits and a newborn child by studying the response of the atria to acetylcholin before and after the administration of strophantin. Methods.The frog hearts were suspended according to Straub and immersed in various solutions (Ringer solution ; solution of strophantin or acetylcholin in Ringer solution); the cannula was kept filled with Ringer solution, which was changed at intervals. The rate of auricular contractions was registered by means of a stop watch.---1