Department of Anatomy and Neurobiology, Northeastern Ohio Universities Colleges of Medicine and Pharmacy Rootstown, OH, USA.
Front Neuroanat. 2010 Oct 19;4:137. doi: 10.3389/fnana.2010.00137. eCollection 2010.
The midbrain tegmentum is the source of cholinergic innervation of the thalamus and has been associated with arousal and control of the sleep/wake cycle. In general, the innervation arises bilaterally from the pedunculopontine tegmental nucleus (PPT) and the laterodorsal tegmental nucleus (LDT). While this pattern has been observed for many thalamic nuclei, a projection from the LDT to the medial geniculate body (MG) has been questioned in some species. We combined retrograde tracing with immunohistochemistry for choline acetyltransferase (ChAT) to identify cholinergic projections from the brainstem to the MG in guinea pigs. Double-labeled cells (retrograde and immunoreactive for ChAT) were found in both the PPT (74%) and the LDT (26%). In both nuclei, double-labeled cells were more numerous on the ipsilateral side. About half of the retrogradely labeled cells were immunonegative, suggesting they are non-cholinergic. The distribution of these immunonegative cells was similar to that of the immunopositive ones: more were in the PPT than the LDT and more were on the ipsilateral than the contralateral side. The results indicate that both the PPT and the LDT project to the MG, and suggest that both cholinergic and non-cholinergic cells contribute substantially to these projections.
中脑被盖是丘脑胆碱能神经支配的来源，与觉醒和睡眠/觉醒周期的控制有关。一般来说，神经支配是双侧的，来自脚桥核被盖部（PPT）和外侧背盖核（LDT）。虽然这种模式已经在许多丘脑核中观察到，但在某些物种中，LDT 到内侧膝状体（MG）的投射一直存在疑问。我们结合逆行追踪和胆碱乙酰转移酶（ChAT）免疫组织化学，以确定豚鼠脑桥到 MG 的胆碱能投射。在 PPT（74%）和 LDT（26%）中都发现了逆行和 ChAT 免疫反应阳性的双标细胞。在两个核中，同侧的双标细胞数量更多。大约一半的逆行标记细胞是免疫阴性的，这表明它们是非胆碱能的。这些免疫阴性细胞的分布与免疫阳性细胞相似：在 PPT 中比在 LDT 中更多，在同侧比在对侧更多。结果表明，PPT 和 LDT 都投射到 MG，并且提示胆碱能和非胆碱能细胞都对这些投射有很大贡献。
