Guinea pig gallbladder and pancreas possess identical CCK-A receptor subtypes: receptor cloning and expression.
Cholecystokinin (CCK) receptors mediate pancreatic acinar secretion and gallbladder contraction. Pharmacological and functional studies in pancreas and gallbladder demonstrate a CCK-A receptor subtype in both tissues. However, some pharmacological studies and affinity cross-linking studies of CCK receptors on pancreatic acini and gallbladder suggest that these two tissues possess two different subtypes of the CCK-A receptor. We cloned these receptors in guinea pig using a cDNA clone of the CCK-A receptor from rat pancreas. The guinea pig gallbladder CCK-A receptor was cloned by hybridization screening of a gallbladder cDNA library using a cDNA probe from the rat CCK-A receptor coding region. The guinea pig pancreas CCK-A receptor cDNA was cloned via the polymerase chain reaction using primers corresponding to the guinea pig gallbladder CCK-A receptor 5'- and 3'-noncoding regions. CCK-A receptor clones from guinea pig pancreas and gallbladder had identical nucleotide sequences, which were 80% homologous to the rat CCK-A receptor cDNA sequence. The deduced amino acid sequence from guinea pig CCK-A receptors was 89% homologous to the rat CCK-A receptor sequence. Dose-inhibition binding studies of transiently expressed receptors by CCK agonists and antagonists exhibited a CCK-A receptor pharmacologically similar to the rat CCK-A receptor. These studies indicate that the CCK-A receptors in guinea pig pancreas and gallbladder are identical and do not support previous proposals that they may represent different receptor subtypes.
De Weerth
A
A
Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Pisegna
J R
JR
Wank
S A
SA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary / Q000302:isolation & purification / Q000378:metabolism; D005704:Gallbladder / Q000378:metabolism*; D015870:Gene Expression; D015723:Gene Library; D006168:Guinea Pigs; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D009928:Organ Specificity; D010179:Pancreas / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D043886:Receptor, Cholecystokinin A; D011949:Receptors, Cholecystokinin / Q000096:biosynthesis* / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012844:Sincalide / Q000031:analogs & derivatives / Q000378:metabolism; D013388:Succinimides / Q000378:metabolism; D014162:Transfection
C044758:Bolton Hunter-cholecystokinin octapeptide; D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D043886:Receptor, Cholecystokinin A; D011949:Receptors, Cholecystokinin; D011994:Recombinant Proteins; D013388:Succinimides; D012844:Sincalide