Departamento de Neurociencias, FES-Iztacala, Universidad Nacional Autónoma de México (UNAM), Av. Los Barrios #1, Col. Los Reyes Iztacala, Tlalnepantla, Mexico, DF, CP 54090, Mexico.
Cell Mol Neurobiol. 2010 Jul;30(5):743-50. doi: 10.1007/s10571-010-9499-7. Epub 2010 Feb 6.
Intracellular recordings were obtained from brain slice preparation in neurons of the striatum of the turtle Trachemys scripta elegans, analogous to the mammalian striatum in its topographic organization, synaptic connectivity, cytoarchitecture, and neurochemistry. Here we show that these similarities extend to the electrophysiological properties of its neurons. Biocytin staining revealed that 85% of the recorded neurons were medium spiny neurons while 15% were aspiny neurons. Spiny neurons of the turtle resembled those found in the mammalian and avian striatum and express dopaminergic D(1) and D(2) class receptors. Because the striatum of the turtle receives a dense dopaminergic innervation from tegmental dopaminergic neurons we investigated the postsynaptic actions of selective dopamine receptor agonists in the excitability of spiny neurons. As in mammals and birds, activation of D(1)-receptors enhances, whereas activation of D(2)-receptors decreases the evoked discharge. Apparently, actions of dopamine agonists occur via the modulation of L-type (Ca(V)1) Ca2+-conductances. Strong cellular evidence suggests that the role of dopamine in the modulation of motor networks is preserved along vertebrate evolution.
在龟 Trachemys scripta elegans 的纹状体脑片制备中获得了细胞内记录，其在地形组织、突触连接、细胞结构和神经化学方面类似于哺乳动物的纹状体。在这里，我们表明这些相似性延伸到其神经元的电生理特性。生物素标记显示，85%的记录神经元为中型棘神经元，而 15%为无棘神经元。龟的棘神经元与在哺乳动物和鸟类纹状体中发现的棘神经元相似，并表达多巴胺 D（1）和 D（2）类受体。由于龟的纹状体从脑桥的多巴胺能神经元接收密集的多巴胺能神经支配，我们研究了选择性多巴胺受体激动剂在棘神经元兴奋性中的突触后作用。与哺乳动物和鸟类一样，D（1）受体的激活增强，而 D（2）受体的激活降低诱发放电。显然，多巴胺激动剂的作用是通过调节 L 型（Ca(V)1）钙电导来实现的。强有力的细胞证据表明，多巴胺在运动网络调制中的作用在脊椎动物进化过程中是保守的。
