Galanin influences on vasopressin and oxytocin release: In vitro studies

Galanin (Gal) acts in the central nervous system as the neuromodulator of the hypothalamo-neurohypophysial system function. Present investigations in vitro were undertaken to study the influence of Gal, added to the incubative media at the concentrations of 10−10, 10−9, 10−8 or 10−7 M, on AVP and OT release from isolated rat hypothalamus (Hth), neurohypophysis (NH) and hypothalamo–neurohypophysial system (Hth–NH).The present results showed that Gal at the concentrations of 10−10, 10−9 and 10−8 M inhibited basal AVP secretion from the all incubated tissues as well as OT release from the NH and Hth–NH explant. On the contrary, 10−10 M Gal was the reason of intensified basal hypothalamic OT secretion.The presence of Gal at the concentrations of 10−10 and 10−8 M in the incubative media enriched in potassium ions excess was the cause of diminished AVP release from the NH and from the Hth–NH explant, respectively. Any effect of Gal on AVP release from the Hth has been observed. All the concentrations of Gal did not exert any effect on OT release from the NH as well as Hth–NH explants. However, the K+-evoked OT release from the Hth was distinctly intensified under influence of 10−10 M as well as 10−8 M Gal.It may be concluded that:–Gal modifies AVP and OT release in vitro at every level of Hth–NH system.–Gal has been supposed to perform the role of central inhibitory neuromodulator for AVP release from the Hth–NH system.–Gal exerts inhibitory effect on OT release in vitro from NH as well intact Hth–NH system but stimulatory influence on OT secretion at the level of Hth.