Possible Interaction: Oxytocin and Sincalide

“Recent studies have shown that CCK stimulates neurohypophyseal secretion of oxytocin (OT) in rats and arginine vasopressin (AVP) in monkeys, and that gastric distention also stimulates OT release in rats.”

“However, intravenous injection of nonsulfated CCK-8 stimulated a significant increase in plasma levels of both OT and VP.”

“Intraperitoneal injection of both nonsulfated and sulfated CCK-8 significantly increased plasma OT levels and had no effect on plasma VP levels.”

“SummaryStudies performed in conscious female … that iv injection of cholecystokinin octapeptide (CCK; 20µ/kg) increased … circulating concentration of oxytocin but not that of vasopressin, and confirmed that the stimulation of oxytocin release was markedly … after iv administration of naloxone (1mg/kg), indicating attenuation of oxytocin release by endogenous opioids.”

“The magnitude of the oxytocin response to the second sucrose solution was increased in a manner related to CCK doses.”

“Stimulation of gastric vagal afferents by systemic administration of cholecystokinin octapeptide (CCK) inhibits gastric motility, reduces food intake, and stimulates pituitary secretion of oxytocin and adrenocorticotropic hormone in rats.”

“The decrease of hypothalamic and neurohypophysial oxytocin content (as brought about by the salt load) was significantly less marked in animals treated simultaneously with CCK-8.”

“injection of CCK-8 (50 ng/day) to euhydrated rats significantly decreased vasopressin and oxytocin content in the hypothalamo-neurohypophysial system.”

“Administration of CCK-8 (20 micrograms/kg iv) increased oxytocin contents in 30-min microdialysates sampled simultaneously within the SON (1.8-fold) and blood (2.4-fold, both P < 0.05) compared with prestimulation levels.”

“In another experiment, after bilateral administration of CCK-8 directly into the SON (10 ng/0.5 microliter) via a microdialysis/infusion probe, oxytocin contents in dialysates sampled from the left and right SON were increased 2.3- and 1.7-fold (P < 0.05), respectively.”

“These results showed that only a small part in the role of OT enhancing EA analgesia was blocked by CCK-8 and naloxone.”

“The decrease of neurohypophysial vasopressin and oxytocin content, brought about by dehydration, was significantly less marked in animals treated with CCK-8.”

“Injection of 5 micrograms CCK-8 IP, but not feeding, caused a marked increase in plasma oxytocin levels.”