LTB4R and Anxiety: GPCRs can not only function as monomers, but also form homodimers or heterodimers among themselves, so GPCRs are the target of numerous medications and are involved in neurological diseases.[40,41] Signal proteins will trigger the anxiety-like behaviors in the GPCR pathway including Akt, p11, and MKP-1 at activating GPCRs.[42] In addition, many orphan receptors are involved in numerous processes in the GPCR family, such as GPR3, GPR6, GPR16, and GPR40, etc. For instance, GPR3 plays a crucial role in various nervous system diseases and emotional reactions by regulating 5-HT and dopamine.