Modulation of parasympathetic neuron phenotype and function by sympathetic innervation

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• 作者：Smith ; Peter G. ; Warn ; J. Donald ; Steinle ; Jena J. ; Krizsan-Agbas ; Dora ; Hasan ; Wohaib
• 关键词：Nitric oxide synthase ; Laser Doppler flowmetry ; Contraction ; Electron microscopy ; Nerve growth factor
• 刊名：Autonomic Neuroscience
• 出版年：2002
• 出版时间：February 28, 2002
• 年：2002
• 卷：96
• 期：1
• 页码：33-42
• 全文大小：409 K

文摘

Selective sympathetic nerve dysfunction occurs during aging and in certain disease states. Here, we review findings concerning the effects of chronic sympathetic denervation on parasympathetic innervation to orbital target tissues in the adult rat. Long-term sympathetic denervation was induced by excising the ipsilateral superior cervical ganglion for 5–6 weeks prior to analyses. Following sympathectomy, pterygopalatine ganglion parasympathetic neurons show reduced nitric oxide synthase protein in their somata and projections to vascular targets. Laser Doppler measurements of ocular blood flow indicate that sympathectomy is also accompanied by reduced nitrergic vasodilatation. In the superior tarsal muscle of the eyelid, parasympathetic varicosities, normally, are distant to smooth muscle cells but make axo-axonal contacts with sympathetic nerves, consistent with physiological evidence showing only prejunctional inhibitory effects on sympathetically mediated smooth muscle contraction. Following sympathectomy, parasympathetic varicosities proliferate and closely appose smooth muscle cells, and this is accompanied by establishment of parasympathetic–smooth muscle excitatory neurotransmission. Many pterygopalatine parasympathetic neurons normally contain nerve growth factor (NGF) protein and express NGF mRNA. However, following chronic sympathectomy or elimination of sympathetic impulse activity, NGF mRNA and protein are markedly reduced, indicating that sympathetic neurotransmission enhances NGF expression in parasympathetic neurons.