Receptor for the peptide hormones gastrin and cholecystokinin (CCK). Expressed throughout the central nervous system, where it modulates processes such as anxiety, analgesia, arousal and neuroleptic activity. Couples to both GNAI1 and GNAQ signaling pathways, but not to GNAS (PubMed:34556863). Upon gastrin activation, reduces glucose absorption in intestinal epithelial cells by downregulating SGLT1 and GLUT2 expression through suppression of the PI3K/Akt/eIF4B pathway (By similarity). In the kidney, decreases SGLT2 expression under high- glucose conditions via ERK/NF-kappa-B signaling (By similarity). {ECO:0000250|UniProtKB:P56481, ECO:0000269|PubMed:34556863, ECO:0000269|PubMed:35672283}. Isoform 2 is constitutively activated and may regulate cancer cell proliferation via a gastrin-independent mechanism. This is the function of CCKBR (cholecystokinin B receptor, Ensembl gene identifier ENSG00000110148).