Antisera raised against eledoisin and kassinin detect immunoreactive material in rat tissue extracts: tissue...

Radioimmunoassays were developed for the tachykinins eledoisin (ELE) and kassinin (KAS) using antisera raised in rabbits. The antisera exhibited low (less than 0.1%) cross-reactivities to substance P (SP) and physalaemin (PHY), but crossreacted (with one exception, antiserum K7) to varying extents with neurokinin A (NKA) and neurokinin B (NKB). In the rat, the tissue distribution of the immunoreactive material detected by antiserum (E7) raised against ELE and by another antiserum (K1) raised against KAS both resembled that previously described for SP. Using the highly KAS-specific antiserum K7, no or only very low levels of immunoreactivity could be detected in extracts of various rat tissues. Gel permeation chromatography and ion-exchange chromatography of tissue extracts indicated that all antisera (except K7) detected the same population of immunoreactive molecules. One of the components was chromatographically indistinguishable from NKA. The tissue distribution of this component also resembled that of SP. Another immunoreactive component co-chromatographed with NKB at cation exchange chromatography. Acid tissue extracts, but not neutral tissue extracts, were found to contain immunoreactive components which appeared more basic than NKA and NKB. The total levels of immunoreactivity were higher in neutral than in acid tissue extracts. However, the ratio between the amounts of immunoreactivities in the two types of extracts varied considerably between tissues, indicating that tachykinin immunoreactive components may be present in different relative proportions in various tissues.