in order to provide anatomical information for a possible pathway involved in pain mechanisms , rats were injected with horseradish peroxidase wheat germ agglutinin ( wga-hrp ) in the centralis lateralis nucleus of the thalamus ( cl ) or in the medial prefrontal cortex ( pfcx ) from which originated retrogradely labelled cells in the dorsal raphe nucleus ( dr ) , locus ceruleus ( lc ) and surrounding structures .
C0019941
horseradish peroxidase
C0078473
wga-hrp