Inhibitory Effect of Methanol Extract of Ganoderma lucidum on Acute Itch-Associated Responses in Mice

In this study, the antipruritic effect of the methanol extract of Ganoderma lucidum (MEGL) was studied in mice. Oral administration of MEGL (10-1000 mg/kg) produced a dose-dependent inhibition of scratching, an itch-related response, induced by intradermal 5-hydroxytryptamine (5-HT) (100 nmol/site), alpha-methyl-5-HT (100 nmol/site), and proteinase-activated receptor-2 (PAR(2))-activating peptide SLIGRL-NH(2) (50 nmol/site). However, MEGL (100-1000 mg/kg) did not inhibit the scratching induced by histamine (100 nmol/site), substance P (100 nmol/site), and compound 48/80 (10 microg/site). These results raise the possibility that MEGL is effective against pruritus mediated by proteinases and 5-HT and that primary afferents expressing PAR(2) and 5-HT(2A) receptors are the sites of its action.