Kinins, a special class of
polypeptides, are represented by
bradykinin (BK),
kallidin (Lys-BK), as well as their metabolites. The biological actions of these
polypeptides binding on their receptors (B1 and B2) have been related to
inflammation process,
cytokines action,
glutamate release and
prostaglandins production. Usually,
kinin B1 receptor is not expressed at a significant level under physiologic conditions in most tissues, but its expression is induced by injury, or upon exposure in vivo or in vitro to pro-inflammatory mediators. The
kinin B2 receptor subtype is constitutively and widely expressed throughout the central and peripheral nervous system. These data raise the possibility for de novo expression of those receptors during the
temporal lobe epilepsy (TLE), which has been related to cell death,
gliosis and hippocampal reorganization. To correlate
kinin system and TLE, adult male Wistar rats were submitted to
pilocarpine model of
epilepsy. The hippocampi were removed 6 h, 5 and 60 days after
status epilepticus (SE) onset. The collected tissues were used to study the expression of
kinin B1 and B2
mRNA receptors, using Real-Time PCR. Immunohistochemistry assay was also employed to visualize
kinin B1 and B2 distribution in the hippocampus. The results show increased
kinin B1 and B2
mRNA levels during acute, silent and chronic periods and changes in the
kinin B1 and B2 receptors distribution. In addition, the immunoreactivity against
kinin B1 receptor was increased mainly during the silent period, where neuron clusters of could be visualized. The
kinin B2 receptor immunoreactivity also showed augmentation but mainly during the acute and silent periods. Our results suggest that
kinin B1 and B2 receptors play an important role in the epileptic phenomena.