Protective effect of T-type calcium channel blocker in histamine-induced paw inflammation in rat

The aim of this paper was to investigate the protective effect of the T-type calcium channel blocker in a model of acute local inflammation (histamine-induced). The intraplantar injection of histamine elicited an inflammatory response that was characterized by a time-dependent increase in paw oedema and neutrophil infiltration in paw tissue. The maximal increase in paw volume was observed at 90 min after histamine administration (maximal paw volume: 0.97 +/- 0.07). In addition, polymorphonuclear leucocyte (PNL) number was markedly increased in the histamine-treated paw tissue (144 +/- 25.56). However, histamine-induced paw oedema was significantly reduced in a dose-dependent manner by treatment with mibefradil (given at 10, 25, 50, and 100 mg kg(-1)) at 30, 60, 90, 120, 150, 180 min after injection of histamine. Mibefradil treatment also caused a significant reduction of the polymorphonuclear leucocyte number in the paw tissue. Our findings support the view that mibefradil exerts antiinflammatory effects. (C) 2001 Academic Press.