Abdul-Razzak R, Bagust J, Kerkut G A
Department of Physiology and Pharmacology, University of Southampton, U.K.
Comp Biochem Physiol Pharmacol Toxicol Endocrinol. 1994 Feb;107(2):205-13. doi: 10.1016/1367-8280(94)90042-6.
The frequency of spontaneous activity recorded from lumbar dorsal roots and the lumbar dorsal horn of isolated spinal cord preparations taken from hamsters aged between 2 days to 8 weeks showed an age dependent sensitivity to 1 mM Mg2+ and 5 microM AP5. Spontaneous dorsal root and dorsal horn activity in cords from animals less than 3 weeks of age was depressed by 1 mM Mg2+ and 5 microM AP5. Cords taken from animals older than 3 weeks showed significantly less depression of spontaneous activity. The application of 10 microM NMDA to the cord produced a small (33%) depression in spontaneous dorsal root and dorsal horn activity in cords from 4 to 6 week old animals. Cords from younger animals exhibited a complex response to NMDA, with an initial increase in spontaneous activity followed by a profound (77%) depression of the firing rate. These results indicate that there are substantial changes taking place in the pharmacology of the dorsal horn during the early weeks of life, and care must be exercised when extrapolating results obtained from neonatal preparations to adult animals.
从2日龄至8周龄仓鼠分离脊髓制备物的腰段背根和腰段背角记录到的自发活动频率，显示出对1 mM Mg2+和5 μM AP5的年龄依赖性敏感性。小于3周龄动物的脊髓中，自发背根和背角活动受到1 mM Mg2+和5 μM AP5的抑制。取自3周龄以上动物的脊髓，自发活动的抑制明显较少。对脊髓施加10 μM NMDA，在4至6周龄动物的脊髓中，自发背根和背角活动产生了轻微（33%）的抑制。较年幼动物的脊髓对NMDA表现出复杂的反应，自发活动最初增加，随后放电频率大幅（77%）降低。这些结果表明，在生命的最初几周内，背角的药理学发生了重大变化，在将从新生制备物获得的结果外推至成年动物时必须谨慎。
