Receptors for cholecystokinin and gastrin

Cholecystokinin (CCK) and gastrin belong to one family of gastrointestinal peptides that regulate a variety of functions in the gastrointestinal tract and in the central nervous system. On the basis of pharmacological, physio logical and molecular studies, receptors for these peptides can be divided into at least two different types: CCKA- and CCKB-receptors. CCKA- and CCKB -receptors are both G-protein coupled receptors and are highly conserved be tween species. Molecular techniques have revealed a distinct species- and t issue-specific variation in receptor expression and pharmacology. In additi on, previously unknown targets for CCK and gastrin such as the kidney were identified. This review discusses the physiological functions of the hormon es CCK and gastrin and their receptors. The molecular structure of these re ceptors and the results of recent structure-function analysis are reviewed.