Purification and biological activity of alligator bradykinin.
Incubation of plasma form the alligator (Alligator mississipiensis) with glass beads in the presence of a kininase inhibitor resulted in the activation of the kallikrein-kinin system and generation of bradykinin-like immunoreactivity. The kinin peptides were purified to homogeneity and were shown to comprise [Thr6]-bradykinin and des-Arg9[Thr6]bradykinin in the molar ratio of approximately 10:1. Bolus injections of synthetic [Thr6]bradykinin into the jugular vein of the anesthetized alligator resulted in a dose-dependent decrease in mean arterial blood pressure. The minimum dose of kinin producing a significant fall in pressure was 0.07 micrograms/kg body wt and the maximum response (25 +/- 6% fall; mean +/- SD, n = 8) was produced by a dose of 0.56 micrograms/kg body wt. The dose producing a half-maximum response was 0.19 +/- 0.08 micrograms/kg. The data indicate that alligator plasma contains all the components of the kallikrein-kinin system found in mammals and suggest that the system may be of physiological importance in the regulation of cardiovascular function in these reptiles.
Comeau
S
S
Regulatory Peptide Center, Creighton University School of Medicine, Omaha, Nebraska 68178.
Lance
V A
VA
Hicks
J W
JW
Conlon
J M
JM
D000489:Alligators and Crocodiles / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001920:Bradykinin / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D008297:Male
D000596:Amino Acids; C062689:bradykinin, Thr(6)-; D001920:Bradykinin