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Researchers have sought to characterize the brain stem neuronal network which instigates vagal innervation of the trachealis muscle in developing sheep. This involved bringing together two complementary retrograde labeling techniques, single neuronal labeling and transneuronal labeling. It was found that the parasympathetic preganglionic neurons which project to the airway smooth muscle of sheep fetuses receive inputs from a regulatory network which covers many of the regions providing premotor control for the respiratory muscles.

The climatology and atmospheric turbidity of Niger are examined using spectral aerosol optical depths from the West African Sahel. The climatic features of this area are conducive to satellite remote-sensing, but such data much be verified by ground observations. The results were similar to those obtained by Ben Mohamed and Frangi (1983, 1986). A localized dust source is not evident in the region, implying that a model of regional dust transport is possible only when Niger's dust transport system is fully understood.

Labeling of vagal motoneurons and central afferents after injection of cholera toxin B into the airway lumen. Am J Physiol Lung Cell Mol Physiol 280: L152-L164, 2001.--We tested the hypothesis that application of the subunit B of cholera toxin (CTB) to the airway mucosa would produce labeling of neuronal somata and sensory fibers in the medulla oblongata. Using [sup.125]I-CTB as a tracer, we demonstrated first that CTB is transported across the trachea] epithelium, but once in the airway wall, it remains confined to the subepithelial space and lamina propria. Despite the rarity of intrinsic neurons in these areas, intraluminal CTB labeled [approximately equals] 10-60 neurons/rat in the nucleus ambiguus and a smaller number of neurons in the dorsal motor nucleus of the vagus. Well-defined sensory fiber terminals were also labeled in the commissural, medial, and ventrolateral subnuclei of the nucleus of the tractus solitarius. Approximately 50 and 90% of the neurons labeled by intraluminal CTB were also labeled by injections of FluoroGold into the tracheal adventitia and lung parenchyma, respectively. These findings demonstrate that a substantial number of medullary vagal motoneurons innervate targets in the vicinity of the airway epithelium. These neurons do not appear to be segregated anatomically from vagal motoneurons that project to deeper layers of the airway wall or lung parenchyma. parasympathetic system; airway ganglia; airway epithelium; retrograde neuronal markers

Perez Fontan, J. Julio, Catherine T. Diec, and Christine R. Velloff. Bilateral distribution of vagal motor and sensory nerve fibers in the rat's lungs and airways. Am J Physiol Regulatory Integrative Comp Physiol 279: R713-R728, 2000.--This study combined single and transneuronal labeling to define the origin of midline-crossing vagal fibers projecting to the rat's lungs. Injections of the [Beta]-subunit of cholera toxin (CT-[Beta]) into the lungs labeled similar numbers of neuronal somata in the nucleus ambiguus and dorsal motor nucleus of the vagus on both sides of the medulla, even though vagal stimulation increased lung resistance 50% less in the contralateral than in the ipsilateral lung. Unilateral cervical vagotomy prevented CT-[Beta] labeling of ipsilateral neuronal somata and sensory fibers, indicating that lung-bound vagal fibers undergo decussation only inside the thorax. Injections of CT-[Beta] and FluoroGold into opposite main stem bronchi double labeled 30% and 11% of all neuronal somata immunoreactive for CT-[Beta] and FluoroGold, respectively, showing that one single vagal motoneuron can innervate airways on both sides. Injections of pseudorabies virus into the right lung revealed a bilateral network of infected neurons, even after unilateral vagotomy. The latter did not prevent infection of the ipsilateral vagal nuclei. These findings demonstrate that vagal motoneurons that project to the lungs receive contralateral inputs from the airway premotor network and vagal bronchomotor centers. parasympathetic system; nucleus ambiguus; dorsal motor nucleus of the vagus; cholera toxin; pseudorabies virus

Perez Fontan, J. Julio, Daniel N. Cortright, James E. Krause, Christine R. Velloff, Vladimir V. Karpitskyi, Terry W. Carver, Jr., Steven D. Shapiro, and Bassem N. Mora. Substance P and neurokinin-1 receptor expression by intrinsic airway neurons in the rat. Am. J. Physiol. Lung Cell. Mol. Physiol. 278: L344-L355, 2000.--Tachykinins and their receptors are involved in the amplification of inflammation in the airways. We analyzed the expression of preprotachykinin-A (PPT-A) and neurokinin-1 (NK-1) receptor genes by intrinsic airway neurons in the rat. We also tested the hypothesis that PPT-A-encoded peptides released by these neurons fulfill the requisite role of substance P in immune complex injury of the lungs. We found that ganglion neurons in intact and denervated airways or in primary culture coexpress PPT-A and NK-1 receptor mRNAs and their protein products. Denervated ganglia from tracheal xenografts (nu/nu mice) or syngeneic lung grafts had increased PPT-A mRNA contents, suggesting preganglionic regulation. Formation of immune complexes in the airways induced comparable inflammatory injuries in syngeneic lung grafts, which lack peptidergic sensory fibers, and control lungs. The injury was attenuated in both cases by pretreatment with the NK-1 receptor antagonist LY-306740. We conclude that tachykinins released by ganglia act as a paracrine or autocrine signal in the airways and may contribute to NK-1 receptor-mediated amplification of immune injury in the lungs. parasympathetic nervous system; autonomic denervation; trachea

La question traitée dans cet article porte sur le monde d’après la pandémie… Représente-t-elle un moment décisif qui va nous faire basculer vers une société plus responsable sur les plans sociaux et environnementaux ? De nouvelles habitudes et de nouveaux comportements responsables vont-ils se mettre en place de manière durable ? Pour répondre à ces enjeux, cet article mobilise des théories plurielles associées aux changements d’habitudes. Des préconisations s’adressant autant aux entreprises, qu’aux décideurs publics ou citoyens sont proposées pour dessiner les contours d’un après-Covid-19 socialement et écologiquement plus acceptable.