van den Hooff P, Seger M A, Burbach J P, Urban I J
Rudolf Magnus Institute for Pharmacology, University of Utrecht, The Netherlands.
Neuroscience. 1990;37(3):647-53. doi: 10.1016/0306-4522(90)90096-m.
Effects of peptides synthesized from the same precursor as vasopressin, i.e. the C-terminal 39-amino acid long glycopeptide and neurophysin II, were investigated for biological activities in electrophysiological experiments in brain slices of the rat lateral septum. These slices contained the glycopeptide as the predominant form and a fragment of it, amino acid sequence 22-39, as a minor form (8% of the glycopeptide 1-39), as shown by high performance liquid chromatography of extracts and by radioimmunoassay. None of the peptides, neurophysin II, the glycopeptide 1-39 and the fragment 22-39, tested in a concentration of 10(-12) M, had measurable effects on the resting membrane potential of the neurons. The glycopeptide and the fragment 22-39, however, increased, in some cells, for tens of minutes the excitatory postsynaptic potentials evoked in these neurons by stimulation of the fimbria fibers. The increase in input resistance, seen in many septal neurons treated with either of the peptides was not correlated with the excitatory postsynaptic potential increase. Neurophysin II affected neither the excitatory postsynaptic potentials nor the input resistance of the neurons. It is concluded that the glycopeptide 1-39 and the fragment 22-39 possess biological activities amongst which the facilitation of excitatory amino acid transmission on lateral septum neurons. Therefore, these peptides derived from the vasopressin precursor may act in concert with vasopressin to establish facilitation of excitatory transmission in the brain.
研究了与加压素由同一前体合成的肽，即C端39个氨基酸长的糖肽和神经垂体素II，在大鼠外侧隔脑片的电生理实验中的生物活性。如提取物的高效液相色谱法和放射免疫测定所示，这些脑片中以糖肽为主要形式，其一个片段（氨基酸序列22 - 39）为次要形式（占糖肽1 - 39的8%）。所测试的肽、神经垂体素II、糖肽1 - 39和片段22 - 39，浓度为10^(-12) M时，均未对神经元的静息膜电位产生可测量的影响。然而，糖肽和片段22 - 39在一些细胞中可使刺激穹窿纤维诱发的这些神经元的兴奋性突触后电位增加数十分钟。在用任一种肽处理的许多隔区神经元中观察到的输入电阻增加与兴奋性突触后电位增加无关。神经垂体素II对神经元的兴奋性突触后电位和输入电阻均无影响。得出的结论是，糖肽1 - 39和片段22 - 39具有生物活性，其中包括促进外侧隔神经元上兴奋性氨基酸的传递。因此，这些源自加压素前体的肽可能与加压素协同作用，在脑中建立兴奋性传递的促进作用。
