The effect of opioid antagonism and environmental restriction on plasma oxytocin and vasopressin concentrations in parturient gilts.

摘要: Oxytocin plays an important role at parturition due to its involvement in uterine contractions, foetal expulsion and the onset of maternal behaviour. The related neurohypophysial hormone, vasopressin, is less clear; however, there some evidence that it also involved behaviour osmotic regulation well established. aim this study was investigate inhibitory effects endogenous opioids on these hormones during expulsive phase pig, examine how opioid restraint interacts with environmental restriction. subjects were 31 Large White × Landrace primiparous sows (gilts). An indwelling jugular catheter implanted under general anaesthesia 12 days before expected day (EPD). From 5 EPD 15 gilts individually housed a restrictive crate without straw 16 straw-bedded pen. Blood samples taken increasing frequency towards through extension reduce disturbance. At 7.5 min after birth first piglet half each environment received dose receptor antagonist naloxone (1 mg/kg, i.v.) remaining receiving saline as control. Overall, no effect either circulating oxytocin or vasopressin. However, both vasopressin inhibited by phase. did not appear have any adverse progress judged cumulative intervals. inhibition discussed relation other neurotransmitters whether part normal' physiological response stress-induced.