Ultrastructural transneuronal degeneration study of axonal elements within the paratrigeminal nucleus in sinoaortic deafferented rats

Abstract

Objective: Morphological study that searched to authenticate thepresence of sinoaortic baroreceptor inputs within the dorsolateralmedullary nucleus under electron microscopy analysis. Methods:After a 5-day survival period, 9 baroreceptor-denervated rats deeplyanaesthetized with equithesin were transcardially perfused andtheir brains were histologically processed. Results: The neuronalcytoarchitecture of the paratrigeminal nucleus comprehends afferentprojections from other nuclei that have a distributive characterregarding visceral and nociceptive functions in the cardiovascularreflex integration response. Conclusion: The medial portion of thenucleus receives afferent projections of the rostral ventrolateralmedulla, as shown by retrograde neurotracing studies. The presentresults show that the medial extent of the paratrigeminal nucleuscontains degenerated axoplasmic cellular components in sinoaorticdeafferented rats. The number of degenerated axonal fibers was alsolarger in this area of the nucleus.

Keywords

• Nerve degeneration
• Trigeminal nucleus
• spinal
• Baroreflex
• Denervation
• Microscopy
• electron
• Medulla oblongata