Computerization of a bioassay: quantitation of slow reacting substance of anaphylaxis (SRS-A)

The bioassay for SRS-A using isolated guinea-pig ileum bathed in atropine and pyrilamine has been computerized resulting in a more accurate collection and calculation of data. Areas under the polygraph tracings are calculated by a computer interfaced with the recording polygraph. After comparison of ileal responses obtained with known amounts of SRS-A standard, the computer determined the relative amounts of SRS-A in unknown samples. The program provided for a correction to adjust for changes in tissue responsiveness. Using this bioassay, we showed that ovalbumin-induced release of SRS-A from sensitized guinea-pig lung was parallel to the release of histamine measured fluorometrically. Ethanol inhibited release of these mediators of anaphylaxis in a similar fashion. Conversely, isoproterenol reduced ovalbumin-induced release of SRS-A to a greater extent than the release of histamine. The versatility of this technique should enable other bioassays to be improved in addition to greatly facilitating the determination of various pharmacologic analyses.