The pineal recess of the opossum: a scanning and transmission electron microcospe study

Scanning and transmission electron microscope studies were performed in the pineal recess region of eighteen adult Didelphis albiventris opossums. With the scanning electron microscope, three concentric regions could be observed in the pineal recess: a central zone lined by cells free of cilia or microvilli, or by a meshwork of interdigitating cell processes; an intermediate zone lined by microvillous cells; and a peripheral zone, lined by ciliated cells. The transmission electron microscope revealed that the central zone is lined mainly by pinealocytes. The lining cells are frequently overlaid by a meshwork of pinealocytic and gliak oricesses. A <> (a meshwork of cellular processes underneath the lining cells) is contantly seen in the central zone. The intermediate zone is lined by elongated microvillous ependymal cells, and the peripheral zone by typical ependyma. The large liquor-contacting area in the pineal recess region, as well as the peculiar organization of its surface, suggest a complex interrelationship between the liquor and the pineal gland of the opossum

Noradrenaline content of the hypothalamus and brain-stem of rats inoculated with Trypanosoma cruzi.

O conteudo de noradrenalina do hipotalamo e do tronco encefalico de ratos controle e inoculados con a cepa Y (300.000 tripomastigotas, i.p.) de Trypanosoma cruzi foi medido pela tecnica fluorimetrica de Anton e Sayre. Os animais foram sacrificados 20 e 32 dias depois da inoculacao. Para avaliacao do grau de desnervacao simpatica do coracao dos animais infectados, a auricula direita foi observada com microscopio de fluorescencia apos tratamento histoquimico pela tecnica do acido glioxilico.O conteudo de noradrenalina do hipolatamo e do tronco encefalico dos animais infectados nao diferiu do medido nos animais controle Contudo, um quase completo desaparecimento das fibras adrenergicas foi observado no coracao dos animais chagasicos, sugerindo que o mecanismo envolvido na lesao discrimina neuronios adrenergicos centrais e perifericos