Urban I J, Killian M J
Rudolf Magnus Institute Medical Faculty, University of Utrecht, The Netherlands.
Neuropeptides. 1990 Jun;16(2):83-90. doi: 10.1016/0143-4179(90)90116-g.
Vasopressin (VP), applied by brief iontophoretic pulses on ventral hippocampus neurons in vivo, excited approximately 30% of the neurons tested. Glutamate (Glu) and acetylcholine (ACh) excited nearly all neurons recorded. A selective antagonist of vasopressin V1 receptors suppressed the VP-induced excitation and, in addition, suppressed the excitations induced by Glu but not those by ACh. The specificity of the action in the brain of this VP antagonist must therefore be doubted. Two excitatory amino acid antagonists, D(-)-2-amino-5-phosphonovaleric acid (2APV) and glutamic acid diethyl ester (GDEE), suppressed the responses to Glu and also those to VP. ACh excitations, tested in the same neurons, were little affected by 2APV and GDEE. The remaining 70% of VH neurons were not excitable with VP. However, the responses of these neurons to Glu but not to Ach, increased markedly both while the peptide was released and for tens of minutes thereafter. The increase in Glu responses induced by VP could not be prevented by the VP or excitatory amino acid receptor antagonists applied before the peptide. The possibility that the excitation and the potentiation of Glu responses caused by VP originated from two different actions of the peptide is discussed.
在体内通过短暂的离子电渗脉冲作用于腹侧海马神经元时，血管加压素（VP）使大约30%接受测试的神经元兴奋。谷氨酸（Glu）和乙酰胆碱（ACh）使几乎所有记录到的神经元兴奋。血管加压素V1受体的选择性拮抗剂抑制了VP诱导的兴奋，此外，还抑制了Glu诱导的兴奋，但不抑制ACh诱导的兴奋。因此，必须怀疑这种VP拮抗剂在脑中作用的特异性。两种兴奋性氨基酸拮抗剂，D-（-）-2-氨基-5-磷酸戊酸（2APV）和谷氨酸二乙酯（GDEE），抑制了对Glu的反应以及对VP的反应。在相同神经元中测试的ACh兴奋，几乎不受2APV和GDEE的影响。其余70%的腹侧海马神经元不能被VP兴奋。然而，这些神经元对Glu而不是对ACh的反应，在肽释放时以及此后的数十分钟内都显著增加。在肽之前应用的VP或兴奋性氨基酸受体拮抗剂不能阻止VP诱导的Glu反应增加。文中讨论了VP引起的Glu反应的兴奋和增强可能源于该肽的两种不同作用的可能性。
