Effects of high doses of diazepam on carrageenin-induced paw edema in rats
Lazzarini, R.; Paulino, C.A.; Malucelli, B.E.; Palermo-Neto, J.
Brazilian Journal of Medical and Biological Research 29(11): 1525-1529
1996
ISSN/ISBN: 0100-879X PMID: 9196557 Document Number: 457002
Benzodiazepine (BDZ) receptor sites play a relevant role in immune/inflammatory reactions. Acute BDZ treatments were shown not only to suppress cell proliferation in rat thymus but also to decrease TNF-alpha, IL-1 and IL-6 release from adult mouse macrophages. In the present investigation the effects of acute (10.0 and 20.0 mg/kg) and long-term (10.0 mg kg-1 day-1, for 21 days) diazepam treatment on carrageenin-induced paw edema were studied in rats. The results showed that acute treatment with high doses of diazepam decreased paw edema volume in a dose-dependent manner, and this effect was observed as early as 1 h after the administration of the 20.0 mg/kg dose and continued until the last measurement was performed (8 h). In contrast, long-term diazepam administration did not modify the phlogistic-induced edema. Taken together, these data show that 1) acute diazepam treatment with high doses decreases the volume of the acute inflammatory paw edema developed by the organism as a response to carrageenin-induced injury, and 2) long-term diazepam treatment induces tolerance to this effect. These results are discussed in the light of a possible effect of diazepam on the components of the rat cellular and humoral immune/inflammatory reaction such as T lymphocytes and/or interleukins.