As a group of intestinal hormones and neurotransmitters, cholecystokinins (CCKs) regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as
Hyla nigrovittata,
Xenopus laevis
, and
Rana catesbeiana
, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander
Tylototriton verrucosus
. This CCK contained an amino acid sequence of DYMGWMDF-NH
2 as seen in other CCKs. A cDNA encoding the CCK precursor containing 129 amino acid residues was cloned from the cDNA library of
T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0x10
-11 mol/L and inducing maximal contraction at a concentration of 2.0x10
-6 mol/L. The EC
50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian.
