Neurotransmitter metabolites in the cerebrospinal fluid of man following physostigmine.

A 3.0 mg dose of physostigmine or normal saline was given intravenously to 23 normal subjects who had been treated with probenecid. Homovanillic acid and 3-methoxy-4-hydroxyphenylglycol concentrations were significantly higher in the lumbar cerebrospinal fluid of subjects who received physostigmine than subjects who received normal saline. This establishes biochemical evidence for a cholinergic link in the central nervous system of man.     

Local generation of kinins in working skeletal muscle tissue in man

The effect of standardized isometric forearm work on circulating and local kinin concentrations was investigated in 12 healthy volunteers using the forearm catheter technique. Radioimmunological kinin determination in arterial blood and in the venous effluent of forearm muscle tissue was performed using a modification of Shimamoto's technique of blood sampling and kinin extraction. Under basal conditions, there was no arterio-venous difference of kinins. Throughout the whole experiment, arterial--reflecting systemically circulating--kinins did not change. In muscle venous blood, immunoreactive kinins were not significantly elevated during work, whereas a marked increase was detected in the recovery period (5.0 +/- 0.6 vs. 10.2 +/- 2.0 pmol/l; p less than 0.01). The data demonstrate, that kinins are locally generated in calculated amounts (32.7 +/- 8.4 fmol/(100 g x min) that are known to be sufficient to induce local vasodilatory and metabolic effects at the site of muscle contraction, but below the threshold for systemic cardiovascular actions.