| abstract |
The present invention provides an agent for prevention and/or treatment of itching comprising a substance capable of suppressing the function involved in signal transduction of GPR4 as an active ingredient. It also provides a nitrogen-containing tricyclic compound represented by the formula (I) or a quaternary ammonium salt thereof, or a pharmaceutically acceptable salt thereof; n n n[wherein R 1 represents substituted or unsubstituted lower alkyl, etc.; R 2 represents hydrogen, substituted or unsubstituted lower alkyl, etc.; R 3 and R 4 are the same or different and each represents hydrogen, lower alkyl, etc.; n represents 0 or 1; X represents —(CH 2 ) 2 —, etc.; and Y represents the formula (II); n n n(wherein W represents CH or a nitrogen atom; Z 1 and Z 2 are the same or different and each represents hydrogen, substituted or unsubstituted lower alkyl, etc.; and Z 3 represents hydrogen, substituted or unsubstituted lower alkyl, etc.)] |