title: Inactivation of kallikrein and kininases and stabilization of whole rat brain kinin levels following focused microwave irradiation.
abstract: Focused microwave irradiation was employed to stabilize endogenous whole rat brain bradykinin levels prior to a simple extraction procedure. Skull microwave exposure (2450 MHz, 3.8 kW., 2.45 sec) resulted in inactivation to less than 5% of control of whole brain kallikrein and kininase activity. Using this adequate exposure duration whole rat brain kinin levels as measured by a sensitive radioimmunoassay were approximately 0.6 pmol/g (wet weight). Further purification of irradiated brain extracts using HPLC revealed that immunoreactive kinin eluted as a single peak that co-chromatographed with authentic bradykinin. Microwave fixation duration of 1.25 sec yielded greatly increased levels of immunoreactive kinin which following HPLC purification eluted in two peaks, corresponding to authentic bradykinin and T-kinin, respectively. The tissue injury resulting from incomplete microwave fixation resulted in the release of kinins. This excess immunoreactive kinin may be derived from cerebral blood, since the predominant form of kinin-generating protein in plasma is T-kininogen.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000528:radiation effects*; D002268:Carboxypeptidases / Q000378:metabolism*; D007610:Kallikreins / Q000037:antagonists & inhibitors* / Q000528:radiation effects; D007700:Kinetics; D007705:Kinins / Q000378:metabolism*; D001121:Lysine Carboxypeptidase / Q000378:metabolism* / Q000528:radiation effects; D008297:Male; D008872:Microwaves; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism* / Q000528:radiation effects; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007705:Kinins; D002268:Carboxypeptidases; D007703:Peptidyl-Dipeptidase A; D001121:Lysine Carboxypeptidase; D007610:Kallikreins