It has been reported that electrical or chemical(i.e. capsaicin) stimulation evoked nociceptive activation inhibits subsequent inflammatory reactions through either hypothalamic-pituitary-adrenal (HPA) axis or adrenal medullary activity, respectively. For these reasons, we evaluated the involvement of these systems, HPA or adrenal medullary activity, in the bee venom (BV) stimulation induced anti-inflammatory effect using zymosan induced leukocyte migration in mouse air pouch model. Subcutaneous BV injection (6 mg/kg) into lower hind limb produced a marked reduction of leukocyte migration. The BV induced inhibitory effect of leukocyte migration was significantly suppressed in adrenalectomized mice. Corticosteroid receptor antagonist (RU486) did not affect the BV induced inhibitory effect of leukocyte migration. Consistently, serum corticosteroid level was not changed by BV pretreatment during zymosan induced inflammation. On the other hand, pretreatment of beta-adrenoceptor antagonist, propranonol, partially but significantly reduced the BV induced inhibitory effect of leukocyte migration up to similar potency in the adrenalectomized animals. Peripheral chemical sympathectomy using 6-hydroxydopamine (6-OHDA) did not affect BV induced anti-inflammatory effect suggesting that symapathetic postganglionic nerve terminal was not involved in BV induced anti- inflammatory effect. However, central chemical sympathectomy by 6-OHDA injection dramatically reduced BV induced anti-inflammatory effect. Moreover, the BV induced inhibitory effect of leukocyte migration was totally suppressed by alpha2-adrenoceptor antagonist, idazoxan (s.c., i.t. and i.c.v. injection). Finally, the BV stimulation produced Fos expression in contralateral part of locus coeruleus (LC) in both normal and inflammatory states. Therefore, our results indicate that BV stimulation may activate the descending alpha2-adrenergic system originated from LC and modulated the adrenal medullary activity.
Source: Korean J Physiol Pharmacol.2001 Dec;5(Suppl II):S99-S100
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