Involvement of steroids in anti-inflammatory effects of PK11195 in a murine model of pleurisy

BACKGROUND: Studies on peripheral benzodiazepine receptor function have yielded a diverse list of activities of which the anti-inflammatory effects need to be further examined. Aims: To evaluate the role of steroids, nitric oxide and adenosine-deaminase in the anti-inflammatory effect of PK11195. Methods: Pleurisy was induced by intrapleural injection of carrageenan in mice pre-treated or not with PK11195. Leukocytes, exudation, adenosine-deaminase (ADA) activity and nitric oxide ( NO) level were measured. Steroid involvement was evaluated by pretreatment with D, L-aminogluthetimide before PK11195. Results: Leukocytes, exudation and NO levels were reduced by PK11195 in the early ( 4 h) phase. In the late ( 48 h) phase, PK11195 decreased leukocytes and ADA activity. D, L-aminogluthetimide reversed the effect of PK11195 on exudate ( 4 h), as well as total and differential leukocytes and NO levels ( 48 h). Conclusions: Steroids, NO and ADA are implicated in the anti-inflammatory action of PK11195.