INFLUENCE OF SOME LOCAL ANESTHETICS UPON THE ADRENALINE CONTRACTION OF ISOLATED STRIPS OF RABBIT AORTA.

Several local anesthetic agents have been tested for their ability to counteract adrenaline-and noradrenaline-induced contractions of the spirally cut strip of rabbit aorta. The method used includes a calibrated spiral spring arrangement attached to a conventional strain gauge transducer. This device which is very useful also for several other isolated organs, is described in detail. All the local anesthetics tested possess anti-adrenaline activity in appropropiate concentrations (1–3 mM), but procaine, mepivacaine and o-methyl-α-propylamino-propionanilide (L 67) are about 5 times more active than lidocaine and cocaine in this respect. The antagonism is non-specific in nature and contractions induced by histamine are counteracted in a similar manner. The results are discussed in relation to the known anesthetic properties of the agents. The conclusion is drawn that the non-specific anti-adrenaline action varies independently of the local anesthetic effect as measured in vitro on the isolated nerve preparation.