Imidazoline I(1) receptor-mediated reduction of muscle rigidity in the reserpine-treated murine model of Parkinson's disease.

Abstract

To explore the therapeutic potential of imidazoline I(1) receptor ligands in motor dysfunction related to the basal ganglia, rigidity was induced in mice by intraperitoneal administration of reserpine. The imidazoline I(1) receptor agonists moxonidine and tizanidine reduced rigidity in a dose-dependent manner. Although rigidity was reduced by efaroxan (an imidazoline I(1) receptor and alpha(2)-adrenoceptor antagonist) and idazoxan (an imidazoline I(1) and I(2) receptor and alpha(2)-adrenoceptor antagonist), SKF86466 and yohimbine, both of which are alpha(2)-adrenoceptor antagonists with no affinity for imidazoline receptors, also suppressed rigidity, suggesting that activation rather than blockade of imidazoline I(1) receptors contributes to reduction of reserpine-induced muscle rigidity.