Kallikrein-kinin system in regulation of submandibular gland blood flow
Orstavik, T.B.; Carretero, O.A.; Scicli, A.G.
American Journal of Physiology 242(6): H1010-H1014
1982
ISSN/ISBN: 0002-9513 PMID: 6283904 Document Number: 194327
Although the glandular kallikrein-kinin system was implicated in the regulation of blood flow (BF) in the salivary glands, its role remains controversial. The role of the kallikrein-kinin system in the regulation of BF in the rat submandibular gland was investigated by increasing endogenous kinin concentration with the kininase II or angiotensin converting enzyme inhibitor (CEI), captopril. To minimize the effect of the CEI mediated by the inhibition of conversion of angiotensin I to II, all rats were nephrectomized 48 h before the experiments. After the administration of the CEI, glandular BF immediately increased from 71 .+-. 6 .mu.l.cntdot.min-1 to 172 .+-. 15 (P < 0.001). To confirm that this effect was mediated by kinins, a group of rats was pretreated with rabbit antibodies to kinins. In response to the CEI, this group's glandular BF only increased from 107 .+-. 12 to 129 .+-. 18 .mu.l.cntdot.min-1. In a group pretreated with Ig from nonimmunized rabbits, BF increased from 103 .+-. 16 to 217 .+-. 16 .mu.l.cntdot.min-1. This response to CEI was not significantly different from that of the nonpretreated rats. The antibodies to kinins did not alone significantly alter glandular BF. Inhibition of plasma kallikrein by administration of soybean trypsin inhibitor did not alter the response to CEI, indicating that plasma kallikrein was not the kininogenase involved. In all the groups studied, the increases in glandular BF after CEI administration were significantly greater (P < 0.001) than in the group pretreated with antibodies to kinins. CEI has no effect on hindlimb blood flow. The increase in submandibular gland BF produced by CEI in the nephrectomized rat apparently is due to kinins probably generated by glandular kallikrein within the organ. The glandular kallikrein-kinin system may participate in the regulation of local BF in organs rich in glandular kallikrein such as the rat submandibular gland.