A. Deweerth et al., GUINEA-PIG GALLBLADDER AND PANCREAS POSSESS IDENTICAL CCK-A RECEPTOR SUBTYPES - RECEPTOR CLONING AND EXPRESSION, The American journal of physiology, 265(6), 1993, pp. 70001116-70001121
Cholecystokinin (CCK) receptors mediate pancreatic acinar secretion an
d gallbladder contraction. Pharmacological and functional studies in p
ancreas and gallbladder demonstrate a CCK-A receptor subtype in both t
issues. However, some pharmacological studies and affinity cross-linki
ng studies of CCK receptors on pancreatic acini and gallbladder sugges
t that these two tissues possess two different subtypes of the CCK-A r
eceptor. 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 polyme
rase chain reaction using primers corresponding to the guinea pig gall
bladder CCK-A receptor 5'- and 3'-noncoding regions. CCK-A receptor cl
ones from guinea pig pancreas and gallbladder had identical nucleotide
sequences, which were 80% homologous to the rat CCK-A receptor cDNA s
equence. The deduced amino acid sequence from guinea pig CCK-A recepto
rs was 89% homologous to the rat CCK-A receptor sequence. Dose-inhibit
ion 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 recep
tors in guinea pig pancreas and gallbladder are identical and do not s
upport previous proposals that they may represent different receptor s
ubtypes.