Murrain M, Murphy A D, Mills L R, Kater S B
Department of Anatomy and Neurobiology, Colorado State University, Fort Collins.
J Neurobiol. 1990 Jun;21(4):611-8. doi: 10.1002/neu.480210408.
We have investigated the cell-specific effect of serotonin (5-HT) on regenerating neurons within the adult central nervous system of the pond snail, Helisoma trivolvis. In culture, 5-HT arrests outgrowth of buccal neurons B19 but not neurons B5 (Haydon, McCobb, and Kater, 1984). After axotomy, neurons within the Helisoma nervous system typically exhibit profuse regenerative outgrowth. This study, on neurons within the CNS, shows that 5-HT selectively inhibits the outgrowth of specific identified neurons, and also causes significant elevations in intracellular calcium concentrations as measured by the calcium indicator dye, Fura-2. The outgrowth of neurons B19 and C1 was selectively inhibited when ganglia were incubated in 5 X 10(-5) M 5-HT. The outgrowth of buccal neurons B5, however, was not affected. Moreover, 5-HT caused significant transient elevations of calcium concentrations in neurons B19 over 30 minutes, but neurons B5 did not show any increases in calcium concentrations with the addition of 5-HT. These results suggest that the effect of 5-HT upon outgrowth of regenerating neurons may be due to an increase in the intracellular calcium concentration.
我们研究了血清素（5-羟色胺，5-HT）对池塘蜗牛（三角帆蚌，Helisoma trivolvis）成体中枢神经系统内再生神经元的细胞特异性作用。在培养过程中，5-HT会抑制颊神经元B19的生长，但不会抑制神经元B5的生长（海登、麦科布和卡特，1984年）。轴突切断后，三角帆蚌神经系统内的神经元通常会表现出大量的再生生长。这项针对中枢神经系统内神经元的研究表明，5-HT会选择性地抑制特定已识别神经元的生长，并且通过钙指示剂染料Fura-2测量发现，它还会导致细胞内钙浓度显著升高。当神经节在5×10⁻⁵ M的5-HT中孵育时，神经元B19和C1的生长受到选择性抑制。然而，颊神经元B5的生长不受影响。此外，5-HT在30分钟内导致神经元B19中的钙浓度显著短暂升高，但加入5-HT后，神经元B5的钙浓度没有任何增加。这些结果表明，5-HT对再生神经元生长的影响可能是由于细胞内钙浓度的增加。
