Identification of bradykinin in mammalian brain.
Bradykinin-like activity was purified from acetic acid extracts of saline-perfused rat brains by gel filtration chromatography and two reverse-phase HPLC systems capable of resolving bradykinin from lysyl-bradykinin and other bradykinin analogs and fragments. Addition of [3H]bradykinin to extracts permitted calculation of recoveries and monitoring of chromatographic fractions. Fractions were examined by radioimmunoassay using a potent and highly specific antiserum raised against bradykinin-human albumin conjugates in rabbits. Bradykinin receptor-active material was also measured by radioreceptor assay using guinea pig ileum, as well as by a bioassay with the estrous rat uterus. Active material chromatographed as authentic bradykinin in all systems. Levels of 0.6 pmol/g whole rat brain were detected, with eight times higher levels in the hypothalamus. Activity increased up to 10-fold following treatment with trypsin; treatment with alpha-chymotrypsin or angiotensin-converting enzyme substantially reduced activity. Similar levels and distribution of bradykinin-like activity were also detected in guinea pig brain extracts. These data substantiate the existence of authentic bradykinin in mammalian brain.
D000818:Animals; D000918:Antibody Specificity; D001920:Bradykinin / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D006168:Guinea Pigs; D007031:Hypothalamus / Q000032:analysis; D007106:Immune Sera / Q000276:immunology; D008297:Male; D011863:Radioimmunoassay; D011869:Radioligand Assay; D051381:Rats; D014018:Tissue Distribution; D014357:Trypsin / Q000494:pharmacology
D007106:Immune Sera; D014357:Trypsin; D001920:Bradykinin