Wodowska Justyna, Ciosek Joanna
Department of Neuropeptides Research, Faculty of Health Sciences, Medical University of Lodz, Narutowicza 60, 90-136 Lodz, Poland.
Department of Neuropeptides Research, Faculty of Health Sciences, Medical University of Lodz, Narutowicza 60, 90-136 Lodz, Poland.
Neuropeptides. 2014 Dec;48(6):387-97. doi: 10.1016/j.npep.2014.10.005. Epub 2014 Nov 10.
Galanin (Gal) and galanin-like peptide (GALP) may be involved in the mechanisms of the hypothalamo-neurohypophysial system. The aim of the present in vitro study was to compare the influence of Gal and GALP on vasopressin (AVP) and oxytocin (OT) release from isolated rat neurohypophysis (NH) or hypothalamo-neurohypophysial explants (Hth-NH). The effect of Gal/GALP on AVP/OT secretion was also studied in the presence of galantide, the non-selective galanin receptors antagonist. Gal at concentrations of 10(-10 )M and 10(-8 )M distinctly inhibited basal and K(+)-stimulated AVP release from the NH and Hth-NH explants, whereas Gal exerted a similar action on OT release only during basal incubation. Gal added to the incubation medium in the presence of galantide did not exert any action on the secretion of either neurohormone from NH and Hth-NH explants. GALP (10(-10 )M and 10(-9 )M) induced intensified basal AVP release from the NH and Hth-NH complex as well as the release of potassium-evoked AVP from the Hth-NH. The same effect of GALP has been observed in the presence of galantide. GALP added to basal incubation medium was the reason for stimulated OT release from the NH as well as from the Hth-NH explants. However, under potassium-stimulated conditions, OT release from the NH and Hth-NH complexes has been observed to be distinctly impaired. Galantide did not block this inhibitory effect of GALP on OT secretion. It may be concluded that: (i) Gal as well as GALP modulate AVP and OT release at every level of the hypothalamo-neurohypophysial system; (ii) Gal acts in the rat central nervous system as the inhibitory neuromodulator for AVP and OT release via its galanin receptors; (iii) the stimulatory effect of GALP on AVP and OT release is likely to be mediated via an unidentified specific GALP receptor(s).
甘丙肽（Gal）和甘丙肽样肽（GALP）可能参与下丘脑 - 神经垂体系统的机制。本体外研究的目的是比较Gal和GALP对离体大鼠神经垂体（NH）或下丘脑 - 神经垂体外植体（Hth - NH）中血管加压素（AVP）和催产素（OT）释放的影响。还在非选择性甘丙肽受体拮抗剂加兰他敏存在的情况下研究了Gal / GALP对AVP / OT分泌的作用。浓度为10^(-10) M和10^(-8) M的Gal明显抑制NH和Hth - NH外植体中基础和K(+)刺激的AVP释放，而Gal仅在基础孵育期间对OT释放有类似作用。在加兰他敏存在下添加到孵育培养基中的Gal对NH和Hth - NH外植体中任何一种神经激素的分泌均无作用。GALP（10^(-10) M和10^(-9) M）诱导NH和Hth - NH复合体中基础AVP释放增强以及Hth - NH中钾诱发的AVP释放增强。在加兰他敏存在的情况下也观察到了GALP的相同作用。添加到基础孵育培养基中的GALP是刺激NH以及Hth - NH外植体中OT释放的原因。然而，在钾刺激条件下，观察到NH和Hth - NH复合体中OT释放明显受损。加兰他敏并未阻断GALP对OT分泌的这种抑制作用。可以得出以下结论：（i）Gal以及GALP在下丘脑 - 神经垂体系统的各个水平调节AVP和OT释放；（ii）Gal在大鼠中枢神经系统中作为通过其甘丙肽受体对AVP和OT释放的抑制性神经调节剂起作用；（iii）GALP对AVP和OT释放的刺激作用可能通过未确定的特定GALP受体介导。
