The application of a scanning and computing cell analyser to neurocytological problems

Inverse enzymatic changes in neurons and glia during increased function and hypoxia

Following stimulation of the vestibular nerve in the rabbit, respiratory enzyme activities increased in Deiters' nerve cells. The anaerobic glycolysis, measured as 10^-4 µl CO₂ per hour per cell, was found to decrease concomitantly by 25 to 40 per cent, suggesting a Pasteur effect. By contrast, in the surrounding glia the anaerobic glycolysis increased and the respiratory enzyme activity decreased, suggesting a Crabtree effect. The evidence is discussed for a regulatory metabolic mechanism operating between the neuron and its glia. Hypoxia of 8 per cent O₂ caused an increase of both oxygen consumption and CO₂ production in the nerve cells, but did not change the glia values.

A kinetic study of the neuronglia relationship

Kinetic studies have been performed on the activity of the succinate oxidizing enzyme complex in living nerve cells and glial cells after increasing duration of stimulation. The nerve cells and glia of the lateral vestibular nucleus were used. The results show a clear difference between the neuron and its surrounding glia. The nerve cell reacted by highly increasing the capacity of the electron transporting system, reflecting an increased consumption of energy as a function of the stimulation. The glia, in contrast, did not change in this respect.

Changes in the base composition of nuclear ribonucleic acid of neurons during a short period of enhanced protein production

Nuclei from isolated nerve cells were sampled by microdissection. The content and composition of the nuclear RNA was studied and compared with that of the cytoplasmic RNA of Deiters' nerve cells of rabbits. Analyses were made of control nerve cells and of cells in which an enhanced RNA and protein production had been induced by chemical means, tricyano-amino-propene, for 60 minutes. The nuclear RNA content of the control nerve cells was 56 µµg, i.e. 3 per cent of the total RNA content of the nerve cell. The base ratios were: adenine 21.3, guanine 26.6, cytosine 30.8, uracil 21.3. Purine-pyrimidine analyses showed that the nuclear RNA differed significantly from the cytoplasmic RNA in having higher adenine and uracil values. The guanine and cytosine values were high, however, and the ratio G/C was 0.86 as compared with 1.16 for the cytoplasmic RNA. The composition of the nuclear RNA was interpreted as reflecting the extraordinarily strong development of the nucleolus in these neurons. During the 60 minutes of enhanced neuronal RNA production (+25 per cent) the guanine value increased and the uracil value decreased significantly in the nuclear RNA. In the cytoplasmic RNA the guanine value also increased although not so much as the nuclear guanine. The cytoplasmic cytosine value decreased. The result indicated that the production of the characteristic cytoplasmic RNA had been influenced by the change in the nuclear RNA

The Denver universal microspectroradiometer (DUM). II. Computer configuration and modular programming for radiometry

This paper describes and discusses for microscopists and spectroscopists the choice of computer equipment and the design of programs used in the Denver Universal Microspectroradiometer (DUM). This instrument is an accurate computerized photon-counting microspectrophotometer, microspectrofluorimeter and microrefractometer. The computer is used to control the operation of the system, to acquire radiometric data of various kinds, and to reduce, analyse and output the data in a readily usable form. Since the radiometer was designed to carry out many kinds of measurements in a variety of micro- and macroscopic specimens, and since different methods of microscopy or spectroscopy have to be combined in various ways fro the study of any one specimen, no single master-program could fulfill efficiently all foreseeable requirements. Therefore, the programming developed is interactive, modular, hierarchical and hybrid. Modular interactive programming makes it possible for almost any kind of main program, applicable to almost any kind of measurement, to be assembled quickly from a collection of hierarchical subroutines. Main programs are short and composed mainly of Fortran statements calling subroutines; subroutines, in turn, automatically call other subroutines over many levels. The subroutines are independently written and optimized for maximum operational efficiency in the computer system used, or for maximum ease of transfer to other systems. This approach to programming enables someone unfamiliar with computer languages to operate the radiometric system from the console of the CRT terminal. The writing of new main programs, by linking groups of existing subroutines, requires only a minimum acquaintance with Fortran; only the writing and revision of subroutines requires programming experience. Differences and similarities in the method of computer operation between the present system and other computerized radiometers are briefly discussed.

Mescaline-induced changes of brain-cortex ribosomes. Effect of mescaline on the stability of brain-cortex ribosomes

1. During the action of mescaline sulphate on goat brain-cortex slices the ribosomal particles become susceptible to breakdown, releasing protein, RNA, acidsoluble nucleotides and ninhydrin-positive materials, resulting in loss of ribosomal enzyme activities. 2. Ribosomes of the mescaline-treated cortex slices undergo rapid degradation in the presence of trypsin and ribonuclease. 3. Mescaline does not alter the chemical and nucleotide compositions or the u.v.-absorption characteristics of ribosomal particles, however.

Sodium and potassium distribution in puffer fish supramedullary nerve cell bodies

The Na and K concentration in single supramedullary neurons of the puffer fish (Spheroides maculatus) was measured using a dual channel integrating ultramicroflame photometer. The cells were frozen in situ, sectioned at low temperatures, and freeze-dried to prevent artefactual movements of cations. The density of the nuclear fragments was 0.15, significantly less than cytoplasm's 0.21. The sucrose-(14)C "space" was 2.1-4.7% in cytoplasm fragments and 0.9-2.1% in nuclear fragments. The K concentration in cytoplasm averaged 134 mmoles/liter tissue volume and in nuclei, 113. The Na concentration in cytoplasm fragments varied between 56 and 138 mmoles/liter per tissue volume; in nuclei between 40 and 135, and in perineural tissue between 55 and 114. This intracellular Na is several times greater than the Na concentration expected from previous estimates. It is probable, however, that the intracellular Na activity is less than half that of the Na concentration, suggesting that much of the intracellular Na is bound to organic molecules within the cell.