Fig. 2.

tVTA/RMTg efferents in the VTA express μORs. (A) Microphotographs illustrating the GAD67 and μOR double labeling in the tVTA/RMTg at a cellular level. GAD67, glutamic acid decarboxylase 67 kDa. (B) Following BDA injection into tVTA/RMTg (Left), μORs were detected within anterogradely labeled axons in the VTA (Right). (C) Following CTb injection into VTA (Left), μORs were observed in retrogradely labeled cell bodies in the tVTA/RMTg (Right). fr, fasciculus retroflexus; IF, interfascicular nucleus; ml, medial lemniscus; RLi, rostral linear nucleus of the raphe; tth, trigeminothalamic tract; xscp, superior cerebellar peduncle decussation.