Mooney R D, Bennett-Clarke C, Chiaia N L, Sahibzada N, Rhoades R W
Department of Anatomy, Medical College of Ohio, Toledo 43699.
J Comp Neurol. 1990 Feb 8;292(2):214-30. doi: 10.1002/cne.902920205.
Immunocytochemistry using antisera directed against dopamine-beta-hydroxylase (DBH) was used to determine the organization of the noradrenergic (NE) input to the hamster's superior colliculus (SC). Immunocytochemistry for DBH was combined with retrograde transport of fluorogold (FG) to determine the sources of NE input to SC. Microiontophoretic techniques were used together with extracellular single unit recording and receptive field mapping techniques to determine the manner in which NE influenced the responses of individual SC neurons. The hamster's SC contained numerous DBH-positive fibers but no immunopositive cells. These fibers formed a plexus that was most dense in the lower stratum griseum superficiale (SGS). The density of DBH-positive fibers was very low in the stratum opticum (SO) and increased in density in the stratum griseum intermediale (SGI) and the other deep layers. When FG injections into the SC were combined with immunocytochemical detection of DBH, double-labeled cells were observed in the contralateral locus ceruleus. DBH-positive neurons were observed in several other portions of the mesencephalon and pons, but none of these were labelled with FG. The effects of NE iontophoresis were assessed for a total of 135 SC neurons. In 74% (N = 100), NE reduced spontaneous and/or stimulus evoked activity. In 3% (N = 4 cells), NE increased activity, and in 23% (N = 31 cells) it had no effect. These percentages were essentially the same for superficial layer visual cells and somatosensory neurons in the deep laminae. The effect of NE iontophoresis upon signal to noise ratios was assessed for 46 visual and 56 somatosensory neurons. For 54% (N = 25) of the visual cells and 16% (N = 9) of the somatosensory cells, NE iontophoresis decreased signal to noise ratios. For 13% (N = 6) of the visual cells and 21% (N = 12) of the somatosensory cells, NE iontophoresis increased signal to noise ratios. The effects of NE on the responsivity of SC neurons were antagonized by propranolol (86% of the 21 cells tested), sotalol (67% of the six cells tested), and atenolol (effective in the single cell tested). All these agents are beta-adrenergic antagonists. The single alpha-adrenergic antagonist that we evaluated, corynanthine, potentiated the effects of NE on the responsivity of the two SC neurons that we tested.
利用针对多巴胺-β-羟化酶（DBH）的抗血清进行免疫细胞化学，以确定去甲肾上腺素能（NE）输入到仓鼠上丘（SC）的组织结构。将DBH的免疫细胞化学与荧光金（FG）的逆行转运相结合，以确定NE输入到SC的来源。微离子电泳技术与细胞外单细胞记录和感受野映射技术一起使用，以确定NE影响单个SC神经元反应的方式。仓鼠的SC含有大量DBH阳性纤维，但没有免疫阳性细胞。这些纤维形成一个丛，在下浅灰质层（SGS）中最密集。DBH阳性纤维在视层（SO）中的密度非常低，在中间灰质层（SGI）和其他深层中密度增加。当将FG注射到SC中并结合DBH的免疫细胞化学检测时，在对侧蓝斑中观察到双标记细胞。在中脑和脑桥的其他几个部分观察到DBH阳性神经元，但这些都没有被FG标记。总共对135个SC神经元评估了NE离子电泳的作用。在74%（N = 100）的神经元中，NE降低了自发和/或刺激诱发的活动。在3%（N = 4个细胞）的神经元中，NE增加了活动，在23%（N = 31个细胞）的神经元中没有影响。对于浅层视觉细胞和深层体感神经元，这些百分比基本相同。对46个视觉神经元和56个体感神经元评估了NE离子电泳对信噪比的影响。对于54%（N = 25）的视觉细胞和16%（N = 9）的体感细胞，NE离子电泳降低了信噪比。对于13%（N = 6）的视觉细胞和21%（N = 12）的体感细胞，NE离子电泳增加了信噪比。普萘洛尔（测试的21个细胞中的86%）、索他洛尔（测试的6个细胞中的67%）和阿替洛尔（在所测试的单个细胞中有效）拮抗了NE对SC神经元反应性的影响。所有这些药物都是β-肾上腺素能拮抗剂。我们评估的单一α-肾上腺素能拮抗剂可力南定，增强了NE对我们测试的两个SC神经元反应性的影响。
