Hyatt-Sachs H, Schreiber R C, Bennett T A, Zigmond R E
Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
J Neurosci. 1993 Apr;13(4):1642-53. doi: 10.1523/JNEUROSCI.13-04-01642.1993.
The expression of neurotransmitters/neuromodulators in sympathetic neurons is regulated by anterograde and retrograde mechanisms. We have examined the role of such mechanisms in the regulation of the neuropeptide vasoactive intestinal peptide (VIP). The adult rat superior cervical ganglion (SCG) contains low levels of peptide-like immunoreactivity (IR) and mRNA for VIP. Some VIP-IR nerve processes, but only a few VIP-IR cell bodies, are detectable. Previous evidence demonstrates, however, that after the SCG is placed in organ culture for 48 hr, the level of VIP-IR and VIP mRNA and the number of VIP-IR cell bodies and fibers increase considerably. Two of the possible causes for these changes in peptide expression in sympathetic neurons are deafferentation and axotomy, both of which occur when the SCG is placed in culture. To determine the importance of deafferentation, the preganglionic cervical sympathetic trunk was cut and the ganglion left in situ. Forty-eight hours later, VIP-IR increased twofold. A corresponding increase in the number of VIP-IR nerve processes was seen, but there was no detectable change in the number of VIP-IR cell bodies. The content of VIP/PHI mRNA also increased by 1.8-fold. The effect of axotomy on VIP-IR was examined by cutting the postganglionic internal and external carotid nerves and leaving the ganglion in situ. Forty-eight hours later, the level of VIP-IR increased 22-fold, many immunostained neurons were found, and the content of VIP mRNA increased over fivefold. After either deafferentation or axotomy, changes in VIP-IR were accompanied by comparable changes in the related molecule peptide histidine isoleucine amide (PHI)-IR. Neuropeptide Y-IR, on the other hand, decreased after deafferentation and increased only twofold after axotomy. The results indicate plasticity in the expression of VIP- and PHI-IR in adult sympathetic neurons in vivo, and suggest that the changes previously seen in organ culture were primarily a response to axotomy.
交感神经元中神经递质/神经调质的表达受顺行和逆行机制调控。我们研究了这些机制在调节神经肽血管活性肠肽（VIP）中的作用。成年大鼠颈上神经节（SCG）中VIP的肽样免疫反应性（IR）和mRNA水平较低。可检测到一些VIP-IR神经纤维，但只有少数VIP-IR细胞体。然而，先前的证据表明，将SCG置于器官培养48小时后，VIP-IR和VIP mRNA水平以及VIP-IR细胞体和纤维的数量会显著增加。交感神经元中肽表达的这些变化的两个可能原因是去传入神经作用和轴突切断，这两种情况在将SCG置于培养时都会发生。为了确定去传入神经作用的重要性，切断节前颈交感干并将神经节留在原位。48小时后，VIP-IR增加了两倍。观察到VIP-IR神经纤维数量相应增加，但VIP-IR细胞体数量没有可检测到的变化。VIP/PHI mRNA的含量也增加了1.8倍。通过切断节后颈内和颈外颈动脉神经并将神经节留在原位来研究轴突切断对VIP-IR的影响。48小时后，VIP-IR水平增加了22倍，发现许多免疫染色的神经元，并且VIP mRNA的含量增加了五倍多。在去传入神经作用或轴突切断后，VIP-IR的变化伴随着相关分子肽组氨酸异亮氨酸酰胺（PHI）-IR的类似变化。另一方面，去传入神经作用后神经肽Y-IR减少，轴突切断后仅增加两倍。结果表明成年交感神经元在体内VIP-和PHI-IR表达具有可塑性，并表明先前在器官培养中看到的变化主要是对轴突切断的反应。
