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Changes during growth in the volume and surface area of cortical neurons in the rabbit

1960; Elsevier BV; Volume: 2; Issue: 2 Linguagem: Inglês

10.1016/0014-4886(60)90005-4

1090-2430

J. P. Schadé, Claude F. Baxter,

Photoreceptor and optogenetics research

A method was developed to measure the surface area of cortical nerve cells. It consists of measuring the proportional volume of the constituents of cortical neurons and their diameter. A modification of the method of Chalkley is developed to determine the volume and surface area of the dendrites. This measurement is accomplished by cementing four tungsten microelectrodes to the diaphragm of the ocular. An attempt has been made to find parallels between quantitative histological measurements and biochemical composition in a specific area of the developing rabbit brain cortex. The proportional volume and surface area of the perikaryal membranes decreased during the first 5 days after birth and then remained practically constant during development. The proportional volume and surface area of the apical and basal dendrites increased markedly from 5 to 30 days after birth. The change in the levels of glutamic acid decarboxylase, γ-aminobutyric acid, and some other amino acids have been measured as a function of age. The largest changes in glutamic acid decarboxylase coincided with the most rapid phase in the development of the surface area of the dendrites. Surface area measurements of neurons in the cerebral cortex may be of value to both the physiologist and the biochemist. For the physiologist the surfaces of the perikarya and dendrites form the receptive part of the neuron. Any interpretation of ion movements and potential differences must take into account the extent of these surfaces. The biochemist might find these measurements a basis for a comparison of enzyme systems associated with cytoplasmic membranes.