Bombesin is a 14-amino-acid peptide found in frog-skin. The human equivalent, gastrin releasing peptide (GRP) has been detected in itch pathways and plays a role in eating behaviors. GRP regulates numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation. Bombesin-SAP specifically targets GRP receptor-positive cells. All other cells are left untouched. Elimination of cells expressing GPR receptor is useful in studying the role of bombesin in itch and eating behaviors.
Bombesin-SAP is a chemical conjugate of bombesin and the ribosome-inactivating protein, saporin. It specifically targets GRP receptor-positive cells.