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Biomedical subjects

J Oliver

Publications and source records attributed to J Oliver.

At least 235 records · Page 13Linked to original sources
PubMed1975

Determinants of experimental neurosis in cats.

In order to assess the relative effectiveness of Masserman's contingent method and Wolpe's noncontingent method of inducing experimental neurosis in cats, cats in four independent groups were trained to a uniform criterion to eat in a standard apparatus and then shocked either contingently upon eating or noncontingently upon eating or noncontingently. Cats shocked noncontingently were matched with those shocked contingently for the number of shocks administered. Ss then were assessed for persistence and/or generalization of the inhibition of eating in the same or in a discriminably-different setting. Masserman's contingent method induced significantly greater inhibition at the 0.5 level. This finding is consistent with prediction that would be made on the basis of the delay-of-reinforcement gradient. It is suggested that the contrasting results obtained by Wolpe and Smart may be attributable to confounding variables introduced unintentionally.

Acoustic Stimulation↗
PubMed1975

Spontaneous and flash-induced multiple unit activity in the hypothalamic gonadotropic areas: effects of photoperiod and of optic nerve section in quail.

The present study was devoted to recording of spontaneous and flash-evoked multiple unit discharges in the gonadotropic areas of the quail hypothalamus and to investigate the influence of the length of the day and of bilateral optic nerve section. Blinding resulted in a marked decrease of MUA in the tuberal region which was musch less important in the dorsal part of the nuclear infundibular complex. Burst and continuous patterns of discharges subsisted in tuberal and dorsal areas of blinded quail but responses to flash were completely suppressed. Lengthening the photofraction led to a very strong reduction of firing rates in both tuberal and dorsal hypothalamic regions. Furthermore, flash stimulation was no longer effective in intact photostimulated quail (18L-6D). Flash-evoked modification of MUA in gonadotropic regions were differentiated in a clear-cut fashion from specific responses which were obtained in the visual system.

Animals↗
PubMed1975

Adaptations in urea ammonium excretion in metabolic acidosis in the rat: a reinterpretation.

1. The effects of oral hydrochloric acid, ammonium chloride, sodium bicarbonate and ammonium bicarbonate on urea and ammonium excretion in rats on a constant diet were studied. 2. Hydrochloric acid acidosis significantly reduced urea excretion in the rat, with an equimolar increase in NH+4 excretion and no change in their sum. In ammonium chloride acidosis, most of the additional nitrogen intake is excreted as NH+4 and a small percentage as urea. The converse holds true after administration of ammonium bicarbonate. The physiological significance of this is discussed. 3. The shift in nitrogen excretion from urea to NH+4 in acidosis is interpreted on the basis of bicarbonate production and utilization. Urea formation utilizes HCO-3. For amino acid sources, this utilization is offset by the metabolism of the carbon skeleton, which gives rise to HCO-3. When waste nitrogen is excreted as NH+4, no bicarbonate is utilized and the new HCO-3, generated by the carbon skeleton, hels to maintain hydrogen ion homeostasis.

Acidosis↗
PubMed1975

Multiple unit activity patterns of neuronal populations in gonadotropic areas of the quail hypothalamus: spontaneous and photically-induced firing.

Multiple-unit activity (MUA) was obtained from neuronal pools in the gonadotropic hypothalamus of quails. A special device allowed for exploration of various hypothalamic structures in unanesthetized birds. All recording sessions were made in the dark. Spontaneous and flash light-evoked MUAs were recorded from both tuberal and dorsal gonadotropic areas, either in the morning or in the afternoon, and were compared to extragonadotropic firing patterns. Firing rates (spikes/10 sec) and integrated MUA (200 addresses) provided distinctive spontaneous neuronal activities for various cell clusters. These spontaneous salient features appeared to be changeable throughout the photoperiod. Flash stimulations resulted in a marked increase in MUA recorded from the gonadotropic regions of the hypothalamus.

Animals↗
PubMed1975

Adaptations in metabolic acidosis: a reinterpretation.

Hydrochloric-acid induced acidosis reduced urea excretion in the rat, with an equimolar increase in NH+4 excreation and no change in their sum. By contrast, in the guinea pig, where ammonium excretion is small, HC1 administration did not effect urea excretion. Ammonium administered as NH4HCO3 was excreted mainly in the form of urinary urea, whereas that administered as NH4C1 was mainly in the form of ammonium. Methionine sulphoximine did not impair the increased ammonium excretion induced by acidosis, but did lead to a marked decrease in plasma glutamine levels and an overall increase in total urinary urea and ammonium nitrogen excretion. A reinterpretation of some aspects of the adaptations to metabolic acidosis is made based on these findings.

Acidosis↗