Observations on neurons and neuroglia from the area of the mesencephalic fifth nucleus of the cat in vitro

Summary Neurons from the mesencephalic root of the fifth nucleus from the kitten have been maintained in vitro for periods up to 70 days. During this time they retained their characteristic form and structure as seen in sectioned material. Axonic processes as long as 8 mm have been measured. The occurrence of recurrent axons intertwining with dendritic arborizations of the same neuron is discussed. Modulations are described for astrocytes in relation to their possible dependence on the scarcity of connective tissue elements and a lack of an outer mesenchymal tissue zone in cultures of mesencephalic explants.Grateful acknowledgment is made to Mrs. Walther Hild and Mrs. C. C. Morris for their generous contribution in the management of the tissue cultures and in executing staining procedures. Messrs G. Lefeber and E. Pitsinger offered indispensable aid with photographic work.This investigation was supported by a grant [PHS B-364 (C3)] from the National Institute of Neurological Diseases and Blindness, of the National Institutes of Health, Public Health Service, administered by C. M. Pomerat.