Battell Emma, Smith Neave, Woodhams Steve, Rich Laura, Donaldson Lucy, Brown Angus, Greenspon Charles, Chapman Victoria, Hathway Gareth
Physiology, Pharmacology and Neuroscience, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom.
Pain Centre Versus Arthritis, The University of Nottingham, Nottingham, United Kingdom.
Pain Rep. 2025 Sep 3;10(5):e1324. doi: 10.1097/PR9.0000000000001324. eCollection 2025 Oct.
The dorsal horn (DH) of the spinal cord is physiologically immature at birth. Spinal excitability increases and wide dynamic range (WDR) neurons in lamina V have lowered activation thresholds and larger receptive field sizes.
The DH is composed of 5 laminae containing diverse interneuronal populations yet our understanding of the physiology of the DH is based on behavioural studies or extrapolation of single cell WDR recordings to the whole network.
We have employed multi-electrode arrays to record contiguous activity across the whole DH in neonatal juvenile, adolescent, and young adult Sprague-Dawley rats after electrical stimulation of the ipsilateral hindpaw (0.01-5 mA).
Baseline DH activity increased significantly ( < 0.0001) over early life, as did DH responses in the post-stimulus period corresponding to A-fibre-mediated input. Age-dependent differences in DH activity during this period were not significantly different in the superficial and intermediate DH, but were in the deep DH. C-fibre-mediated activity was more variable and, unlike the A-fibre period, there were no significant differences in stimulus response profiles. However, significant C-fibre-evoked activity was detected in juvenile, adolescent, and adult groups across the whole array and particularly in the deep DH ( < 0.05 and < 0.01). Finally, short-term plasticity ("wind-up"), previously observed with single-unit approaches was detected in all regions of the adult rat DH, but not in younger ages.
Despite behavioural and single-cell responses being more excitable in early life, at a network level the DH is significantly less excited than in adulthood.
脊髓背角（DH）在出生时生理上不成熟。脊髓兴奋性增加，V层中的广动力范围（WDR）神经元的激活阈值降低，感受野更大。
DH由5层组成，包含不同的中间神经元群体，但我们对DH生理学的理解基于行为学研究或将单细胞WDR记录外推至整个网络。
我们使用多电极阵列记录了在对同侧后爪进行电刺激（0.01 - 5 mA）后，新生、幼年、青少年和年轻成年Sprague-Dawley大鼠整个DH的连续活动。
在生命早期，基线DH活动显著增加（<0.0001），对应于A纤维介导输入的刺激后时期的DH反应也增加。在此期间，浅部和中部DH的DH活动的年龄依赖性差异不显著，但深部DH有差异。C纤维介导的活动变化更大，与A纤维时期不同，刺激反应曲线没有显著差异。然而，在整个阵列中，尤其是在深部DH（<0.05和<0.01），在幼年、青少年和成年组中检测到显著的C纤维诱发活动。最后，在成年大鼠DH的所有区域均检测到了先前在单细胞研究中观察到的短期可塑性（“wind-up”），但在较年轻的年龄段未检测到。
尽管在生命早期行为和单细胞反应更易兴奋，但在网络水平上，DH的兴奋程度明显低于成年期。
