Release of oxytocin and substance P-like peptides from the rat posterior pituitary lobe incubated in situ after infusion of hypertonic solution into the third cerebral ventricle.

Release of oxytocin and Substance P-like peptides from the rat posterior pituitary lobe incubated in situ after infusion of hypertonic solution into the third cerebral ventricle. Acta Physiol. Pol., 1978, 29 (1): 9-16. The experiments were carried out on male rats. Under general urethane and chloralose anaesthesia the ventral surface of the hypothalamus and the pituitary gland were exposed by a transpharyngeal approach and the anterior pituitary lobe was entirely removed. The posterior lobe with the remaining neural and partially vascular connections with the hypothalamus was incubated in situ. Oxytocin and Substance P-like peptides were assayed biologically in six 20-min samples of the fluid outflow from the posterior pituitary lobe incubated in situ. At the beginning of collection of the fourth sample a hypertonic solution was infused into the third ventricle through a micropipette. This infusion increased significantly the release of oxytocin and insignificantly that of Substance P-like pepides from the posterior pituitary lobe into the incubation fluid.