Copeptin, a surrogate marker of arginine8 vasopressin, has no ability to modulate human and mouse gastric motility

Abstract Copeptin, a glycosylated peptide fragment derived from the C-terminal region of precursor arginine8 vasopressin (AVP), is co-secreted with AVP in equimolar amounts. Elevated plasma modulates gastric motility so we investigated whether copeptin had similar effect. Copeptin (10-9-10-7M), and (10-12-10-5M), were evaluated for their ability to modulate spontaneous electrically-evoked (EFS) contractions human proximal distal circular muscle vitro. Similar experiments performed on mouse stomach re-examined published effect aorta. In presence tetrodotoxin (10-6M), atropine (10-6M) L-NAME (3 × 10-4M), contracted spontaneously rhythmically as did stomach. no baseline tone or myogenic either However, concentration-dependently increased tone, amplitude frequency both regions potency (pEC50 9.0-9.5; n = 4) threshold concentration (10-11-10-10M). was similarly active EFS-evoked cholinergic (human mouse) unaffected by peptides relaxations copeptin. sub-maximally aorta elevated (10-7M) (cf. previously study) but reduced carbachol sodium nitroprusside (10-3M). We conclude that contrast AVP, over range reported has direct