INDIRECT ROLE OF beta(2)-ADRENERGIC RECEPTORS IN THE MECHANISM OF ANTI-INFLAMMATORY ACTION OF NSAIDS

In this study we investigated both intact and adrenalectomized rats to determine whether or not the anti-inflammatory effects of indomethacin, diclofenac sodium, ibuprofen, nimesulide, tenoxicam and aspirin (IDINTA) are related to adrenal gland hormones in carrageenan-induced inflammation model of rats. Also, we investigated the anti-inflammtory action mechanism of hormones (adrenalin, cortisol) which perform a role in the anti-inflammatory effect of IDINTA on the adrenergic receptors. The results show that IDINTA produces significant anti-inflammatory effects in intact rats (ID50: 9.82, 10.81, 95.21, 75.23, 8.21 and 61.84 mg/kg), but insignificant effects in adrenalectomized rats (ID50: 152.97, 188.17, 1275.0, 433.67, 188.16 and 1028.17 mg/kg). In addition, adrenalin and prednisolone caused anti-inflammatory effect rates of 78.3% and 95.7% respectively in adrenalectomized rats. The anti-inflammatory effects of adrenalin and prednisolone did not change when prazosin (alpha 1-receptor blocker), yohimbine (alpha 2-receptor blocker) and phenoxybenzamine- (alpha 1- and alpha 2- receptor blocker) were given to rat groups; however, in adrenal ecto in zed rats administered with propranolol (a non-selective blocker of beta 1 and beta 2-receptors) the anti-inflammatory effect of adrenalin was lost, and that of prednisolone decreased to 36.2%. It was also found that metoprolol (a selective blocker of PI-receptors) did not alter the anti-inflammatory effects of the drugs. As a result, it was shown that anti- inflammatory effects of IDINTA are related to adrenalin and cortisol (corticosterone in rats). It was also determined for the first time that adrenalin (totally) and prednisolone (partially) triggered anti- inflammatory effects via the beta(2)-receptors but not via the alpha(1), alpha(2) and beta(1)-receptors.