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;
[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);
(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.)]
本发明提供了一种用于预防和/或治疗瘙痒的药剂,其包括一种能够抑制GPR4信号传导功能的物质作为活性成分。它还提供了一种氮杂
三环化合物,其表示为式(I)或其季
铵盐,或其药学上可接受的盐;其中,R1表示取代或未取代的低碳基等;R2表示氢,取代或未取代的低碳基等;R3和R4相同或不同,每个表示氢,低碳基等;n表示0或1;X表示—(
CH2)2—等;Y表示式(II);(其中,W表示CH或氮原子;Z1和Z2相同或不同,每个表示氢,取代或未取代的低碳基等;Z3表示氢,取代或未取代的低碳基等。)