Pineda J, Ruiz-Ortega J A, Martín-Ruiz R, Ugedo L
Department of Pharmacology, Faculty of Medicine, University of the Basque Country, Vizcaya, Spain.
Neurosci Lett. 1996 Nov 22;219(2):103-6. doi: 10.1016/s0304-3940(96)13180-3.
Agmatine (decarboxylated arginine) has been proposed as an endogenous ligand for non-adrenoceptor, imidazoline binding sites, but also binds to alpha 2-adrenoceptors. The interaction of agmatine with alpha 2-adrenoceptors was evaluated by studying the effect of agmatine on the firing rate of locus coeruleus (LC) neurones using extracellular recordings in anesthetized rats and rat brain slices. In vivo, local application of agmatine into the LC caused a slight and short-lasting increase in cell firing rate (P < 0.005). In vitro, agmatine failed to change the firing rate of LC neurones nor did it antagonize the inhibitory effect of noradrenaline on these cells. Since alpha 2-adrenoceptors are known to inhibit the firing of LC cells, we conclude that agmatine does not have agonist or antagonist properties at alpha 2-adrenoceptors of these neurones.
胍丁胺（脱羧精氨酸）已被提出作为非肾上腺素能咪唑啉结合位点的内源性配体，但它也能与α2-肾上腺素能受体结合。通过在麻醉大鼠和大鼠脑片中进行细胞外记录，研究胍丁胺对蓝斑（LC）神经元放电频率的影响，以此来评估胍丁胺与α2-肾上腺素能受体的相互作用。在体内，向LC局部应用胍丁胺会导致细胞放电频率轻微且短暂增加（P < 0.005）。在体外，胍丁胺未能改变LC神经元的放电频率，也未拮抗去甲肾上腺素对这些细胞的抑制作用。由于已知α2-肾上腺素能受体可抑制LC细胞的放电，我们得出结论：胍丁胺在这些神经元的α2-肾上腺素能受体上不具有激动剂或拮抗剂特性。
