Myotropic peptide. In larvae, both sulfakinin and sulfakinin(6-14) are expressed in the CNS but not the ring gland, thoracic perisympathetic organs (tPSO) and abdominal perisympathetic organs (aPSO) (at protein level). In adults, both sulfakinin and sulfakinin(6-14) are expressed in the brain and thoracic-abdominal ganglion but not in corpora cardiaca and corpora allata (at protein level). Detected in larvae and adults. Belongs to the gastrin/cholecystokinin family.