Synaptic convergence of motor and somatosensory cortical afferents onto GABAergic interneurons in the rat striatum

Cortical afferents to the basal ganglia, and in particular the corticostriatal projections, are critical in the expression of basal ganglia function in health and disease. The corticostriatal projections are topographically organized but also partially overlap and interdigitate. To determine whether projections from distinct cortical areas converge at the level of single interneurons in the striatum, double anterograde labeling from the primary motor (M1) and primary somatosensory (S1) cortices in the rat, was combined with immunolabeling for parvalbumin (PV), to identify one population of striatal GABAergic interneurons. Cortical afferents from M1 and S1 gave rise to distinct, but partially overlapping, arbors of varicose axons in the striatum. PV-positive neurons were often apposed by cortical terminals and, in many instances, apposed by terminals from both cortical areas. Frequently, individual cortical axons formed multiple varicosities apposed to the same PV-positive neuron. Electron microscopy confirmed that the cortical terminals formed asymmetric synapses with the dendrites and perikarya of PV-positive neurons as well as unlabelled dendritic spines. Correlated light and electron microscopy revealed that individual PV-positive neurons received synaptic input from axon terminals derived from both motor and somatosensory cortices. These results demonstrate that, within areas of overlap of functionally distinct projections, there is synaptic convergence at the single cell level. Sensorimotor integration in the basal ganglia is thus likely to be mediated, at least in part, by striatal GABAergic interneurons. Furthermore, our findings suggest that the pattern of innervation of GABAergic interneurons by cortical afferents is different from the cortical innervation of spiny projection neurons.     

光度法测定咖啡因、烟酰胺、水杨酸等配体与萘普生在水溶液中的形成常数

本文通过萘普生和咖啡因、烟酰胺、水杨酸等配体紫外光谱的测定,Job连续递变法实验,确定了它们之间的相互作用。其形成物的比值均为1:1。并用紫外分光光度法测定了形成常数,进而推算了热力学函数,推测了其可能的形成机理。     

Anatomic and radiologic bases of surgery of the thoracic aorta

Summary Lesions of the thoracic aorta create problems related to their site and relations with the main aortic branches. The aim of surgery must be to treat the lesion while ensuring perfusion of the tissues excluded by clamping during the operation. Anatomic study of the aortic lesions is based on imaging. Angiography is still often the basic examination though it shows only the lumen and course of the aorta. However, CT and MRI visualise the aortic wall and especially the relations of the aorta to the mediastinal structures. A comparison of anatomic and imaging studies was made on 10 fresh subjects coming from the anatomy department of the Saints-Pères and from the school of surgery of Fer à Moulin. Sections were made every 3 to 5 mm in 3 planes (sagittal, coronal and axial) after CT localisation of the plane of section. This anatomic study was correlated with CT and MR images made on healthy volunteers. The choice of surgical management of a lesion of the thoracic aorta is based on preoperative anatomic assessment by imaging applied not only to the aorta but also to its branches and the territory supplied.

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Bases anatomo-radiologiques de la chirurgie de l'aorte thoracique

Résumé Les lésions de l'aorte thoracique posent le problème de leur siège et de leurs rapports avec les principales collatérales de l'aorte. La stratégie chirurgicale doit permettre de traiter la lésion et d'assurer pendant l'intervention la perfusion des tissus exclus par le clampage. L'étude anatomique des lésions de l'aorte repose sur l'imagerie. L'angiographie reste encore souvent l'examen de base bien qu'elle ne montre que la lumière et le trajet de l'aorte. En revanche, la tomodensitométrie et l'IRM visualisent la paroi aortique mais surtout les rapports de l'aorte avec les structures médiastinales. Une confrontation anatomie - imagerie a été entreprise sur 10 sujets frais du Laboratoire d'Anatomie des Saints-Pères et de l'Ecole de Chirurgie du Fer à Moulin coupés tous les 3 à 5 mm dans les 3 plans (sagittal, coronal et axial) après repérage tomodensitométrique (TDM) du plan de coupe. Cette étude anatomique a été correlée à l'imagerie tomodensitométrique et l'imagerie par résonance magnétique (IRM) obtenues sur des volontaires sains. Devant une lésion de l'aorte thoracique, le choix de la stratégie chirurgicale repose sur le bilan anatomique pré-opératoire (imagerie) qui doit tenir compte de l'aorte mais aussi de ses collatérales et du territoire vascularisé.