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Biomedical subjects

W B Quay

Publications and source records attributed to W B Quay.

At least 55 records · Page 3Linked to original sources
PubMed1979

Daily rhythmic changes in synaptic vesicle contents of nerve endings on adrenomedullary adrenaline cells, and their modification by pinealectomy and sham operations.

Nerve endings on adrenaline cells in male rat adrenal medullas were investigated by quantitative electron microscopy, with sampling at 8 times during a standard light: dark (12:12) photoperiod. Number (N) per unit area of 2 vesicle types (small clear vesicle, SCV; large granular vesicle, LGV) and % of LGV per total vesicle N were determined. Normal (non-operated) animals showed a circadian rhythm (p less than 0.005) in mean SCVN and one with nearly opposite phase relations in % LGVN. Doubly sham-operated animals had a similar rhythm in %LGVN but diminished circadian change in SCVN. Pinealectomized animals had a circadian pattern in SCVN, but this differed from that of normals in having a 2nd peak, a delay or phase shift of the primary peak, and an increased amplitude of the rhythmic changes.

Adrenal Medulla↗
PubMed1979

Biogenic amines in neuroendocrine systems: multiple sources, messages, targets and controls.

Biogenic amines are small chemical mediator molecules synthesized from amino acids by the body. Our research has centered on functions and controls of three categories of biogenic amines in neuroendocrine and neural systems of laboratory species of mammals as models of similar processes in the human body. Experimental analyses have been made of possible contributions of particular of these compounds, or their sources, to regulation of reproductive and 24-hour rhythms, and to responses and adaptations to stress. Results from this and related work, by many other investigators as well, have general implications for biomedical research, including: (A) Biogenic amines have multiple sources, messages, targets and possible controls, depending on species (genetics), developmental stage and age, and in relation to tissue regions and responses during both adaptations and disease states. (B) Functions or actions of biogenic amines in either the nervous or the neuroendocrine system go beyond what can be accommodated by the classical paradigms or terms of neurophysiology. Labeling these compounds in their various tissue sites as "neurotransmitters", or "neuromodulators", or "neurohormones" adds little to our understanding of their actions and roles. (C) Future understanding of how these chemical mediators function and are controlled in health and in disease should be enhanced by investigation of the spectrum of adaptive tissue changes in which these compounds and their control mechanisms participate. This suggested approach contrasts with the usual and classic paradigm in which primary, if not unitary, sources, actions and controls are emphasized to the exclusion and ignoring of others that may have vital significance at particular times or in particular circumstances.

Animals↗
PubMed1978

Quantitative characteristics of the Feyrter cells and neuroepithelial bodies of the fetal rabbit lung in normoxia and short term chronic hypoxia.

We report here quantitative data on the Feyrter (single) cells (APUD cells) and neuroepithelial bodies (grouped Feyrter cells), in the lungs of rabbit fetuses at 26, 27.5 and 29 days gestational age, during normoxia and short term chronic hypoxia. The apparent number of these cells declines during this period; we suggest that this might be due to increased hypoxemia. Moreover, the number of cells in the lungs of fetuses from short term chronically hypoxic mothers is lower than in the normoxic animals. These findings are in agreement with our previous studies in short term chronically hypoxic neonatal rabbits, and suggest that the increased hypoxemia in the fetus, caused by the induction of hypoxia in the mother, constitutes a stimulus for secretory activity of the Feyrter cells and neuroepithelial bodies (NEBs). This in turn could be part of the mechanism responsible for maintaining the pulmonary vasoconstriction due to hypoxemia. Our results from fetuses of normoxic does provide base line data on the chronological importance of the Feyrter cells and NEBs.

APUD Cells↗
PubMed1978

A radioautographic study of the neuroepithelial bodies of the lungs in fetal and neonatal rabbits.

The neuroepithelial bodies (NEB's) of the lung of 29-day-old fetuses and 1-day-old rabbits, under the conditions of this study, neither take up 3H-thymidine nor undergo mitosis. Also the NEB's are not derived at these times from proliferations of other kinds of epithelial cells in the intrapulmonary airways. It is, therefore, suggested that the difference in numbers of NEB's previously observed by us, between the 29-day fetus and the 1-day-old rabbit, is due either to regranulation or acquisition of argyrophilic material by the NEB's or differentiation of other epithelial types. It is concluded that the NEB's are composed of well differentiated cells, which have a greatly reduced capacity to undergo mitosis.

APUD Cells↗
PubMed1978

Quantitative morphology and environmental responses of the pineal gland in the collared lemming (Dicrostonyx groenlandicus).

Collared lemmings from Churchill, Manitoba, and their descendants were studied in captivity to define neuroendocrine and related histophsiological characteristics and responses, particularly in relation to photic and temperature conditions. Relatively great pineal size (0.1755 +/- 0.0167 mm3, or 3.08 +/- 0.30 = pineal volume in mm3 X 10(3)/body weight in gm; N = 16) shown in this arctic rodent is consistent with the suggestion that pineal size and significance may tend to be greater in more northern (higher latitude) species. Total number of nucleated cells per pineal averaged 137,000 +/- 10,500. Pinealocytes (105,000 +/- 8,700/pineal) and other cell types were present in relative numbers typical of mammalian pineal glands, and were not numerically correlated with age, sex, or location or circumstances of birth and early postnatal life. Chronic exposure to warmer (21-27 degrees C) in comparison with colder (-9 to -6 degrees C) environments, whatever the illumination, led to greater pinealocyte activity, as shown especially by nucleolar diameter, throughout most of the nine regions of the organ analyzed cytologically (all regions combined: P less than 0.001). Increased pinealocyte activity in chronic darkness was suggested by similar evidence (P less than 0.01), but in comparison with the thermal effects, was less marked and more variable in different regions of the organ. These and other findings of this study indicate that the Dicrostonyx pineal organ is morphologically unique, relatively large in size, and cytologically responsive to environmental conditions.

Animals↗
PubMed1978

Hypothalamic dopamine-beta-hydroxylase activity: fluctuations with time of day and their modifications by intracranial surgery, adrenalectomy, and pinealectomy.

Hypothalamic and plasma dopamine-beta-hydroxylase [DBH, EC 1.14.2.1] activites were measured by a coupled radioenzymatic method. Animals representing five experimental groups [intact controls, adrenalectomized, pinealectomized, adrenalectomized pinealectomized, doubly sham-operated] were killed and sampled at 8 times through the 24-hr daily cycle, 15 days postoperation, and at 50-52 days of age. Hypothalamic DBH in intact control animals had statistically significant fluctuations in relation to time of day. These changes were lost or dampened in groups that had had intracranial surgery and were characteristically shifted by adrenalectomy, either alone or with pinealectomy. Plasma DBH fluctuations in the same animals resembled those in hypothalamus in some features (e.g., peak near mid-dark; shift in daily maxima and minima after adrenalectomy) and differed in others [e.g., no effect of intracranial surgery or of sham operation; adrenalectomized pinealectomized animals resembled the solely pinealectomized]. Although temporal patterns in hypothalamic DBH activity thus differed in the experimental animal groups, the daily means of hypothalamic DBH activity were similar.

Adrenalectomy↗
PubMed1978

Effects of pinealectomy and of sham-pinealectomy on blood glucose levels in the alloxan-diabetic rat.

Alloxan-diabetic male rats were used to test effects of pinealectomy (PX) and of sham-pinealectomy (SPX) on blood glucose levels at mid-dark in the daily light-dark (LD 12:12) cycle. Animals received a diabetogenic dose of alloxan 10 days postoperatively. Blood glucose was measured on days -1,1,2,3,4,5,7,10 and 15 after 8-hour fasts. Pinealectomized (PX) and non-operated (C) animals were equivalent in their hyperglycemia following alloxan. SPX animals contrastingly showed significantly less response to alloxan than did animals of the other two groups. This difference of the SPX animals was in terms of lower hyperglycemia, better maintenance of body weight and of survival. It is concluded that intracranial surgery alone (SPX) and without visible brain damage can affect mechanisms of glucose homeostasis, and that at least in some circumstances such a surgical effect is not only different from effects of surgical pinealectomy (PX), but is also probably not pineal-dependent.

Alloxan↗
PubMed1977

Modification of hydroxyindole-O-methyltransferase activity in experimental pineocytomas induced in hamsters by a human papovavirus (JC).

Hydroxyindole-O-methyltransferase (HIOMT) (HIOMT) activity was studied and compared in 7 pineal tumors (pineocytomas) induced in vivo in Syrian hamsters after postnatal inoculation with strains of human papovavirus (JC). Levels of tumor HIOMT activity were correlated with degree of cytologic differentiation of the pineocytes of each neoplasm, as judged from electrom micrographs. The relative capacities of the HIOMT in the tumors to methylate three related substrates gave similar ratios in the individual tumors and were not different from those of HIOMT in normal hamster pineal glands.

Acetylserotonin O-Methyltransferase↗
PubMed1977

Quantitative characteristics of the Feyrter (APUD) cells of the neonatal rabbit lung in normoxia and chronic hypoxia.

Our studies show that the apparent number of Feyrter cells in the lung declines during the neonatal period in normoxic rabbits, and that in hypoxic animals a uniformly and significantly lower number of cells occurs as compared with the normoxic rabbits. There is some indication of degranulation of cells in the hypoxic groups. It is suggested that environmental and/or physiological factors associated with the start of extrauterine life, or lung development, may affect the apparent number and probable level of activity of these cells. These changes seem to be enhanced by hypoxia. Mast cells are scarce, and Feyrter cells are relatively more numerous along the airways. These cell types could possibly represent storage sites for 5-hydroxytryptamine, as suggested also by other investigators. Intraepithelial nerve fibres in bronchi and bronchioles were found but they were not limited to innervations of Feyrter cells or related cell bodies.

APUD Cells↗
PubMed1976

Effects of continuous light and darkness, and of pinealectomy, adrenalectomy and gonadectomy on uptake of 3H-serotonin by the suprachiasmatic nuclear region of male rats.

Rats exposed to continuous light show no significant differences in serotonin (5-HT) uptake by the suprachiasmatic nuclear region (SNR) at 10.00 and 22.00 L, while in continuous darkness, the uptake at 10.00 D is significantly higher than uptake at 22.00 D. In consideration of the role of the suprachiasmatic nucleus in light-mediated control of neuroendocrine activity, this suggests endogenous generation or control of this uptake rhythm. An effect of sham-pinealectomy in decreasing 5-HT uptake was found, but cannot be fully interpreted at this time. The lack of effect of castration or adrenalectomy suggests that these endocrines have little if any direct effect on 5-HT mechanisms in the SNR.

Adrenalectomy↗
PubMed1976

Hypothalamic and suprachiasmatic uptake of serotonin in vitro: twenty-four-hour changes in male and proestrous female rats.

Twenty-four-hour changes in the in vitro serotonin (5-HT) uptake capacity of hypothalamic homogenates and of "Vibratome" slices of the suprachiasmatic nuclear region (SNR) of the hypothalamus were studied in 60-90-day-old Holtzman (albino) rats. Animals acclimated to artificially illuminated (fluorescent, LD 12:12) and temperature controlled (22 +/- 2 C) rooms were killed 6% each of 8 time points. Synaptosomal fractions from homogenates of whole hypothalamus, and slices of the SNR were incubated for 20 min in Krebs-Henseleit buffer with [3H]5-HT. Males showed a single daily peak in SNR uptake at the start of darkness, and a minimum near the onset of light, while a more complex pattern containing 3 peaks and minima occurred in uptake by hypothalamic homogenates. Proestrous females showed a single high amplitude peak SNR uptake during the critical period, just prior to the plasma LH peak determined in the same animals by radioimmunoassay. It is suggested that this short-term and 4-fold increase in SNR uptake of 5-HT may serve to limit free 5-HT and its inhibitory or other effects on the gonadotropin release hormone system and thereby on LH release and ovulation.

Animals↗
PubMed1975

Hypothalamic 24-hour rhythms in histamine, histidine, decarboxylase and histamine-N-methyltransferase.

Twenty-four hour rhythms of histamine (H), its biosynthetic enzyme, L-histidine decarboxylase (EC 4.1.1.22, HD) and its inactivation enzyme, histamine N-methyltransferase (EC 2.1.1.8, HMT) were assayed in the 63-day-old male rat hypothalamus using a modified single isotopeenzyme microassay. H was found to have a 24-h rhythm with a maximum concentration at 11:00 h (lights on 10:00-22:00 h) and a minimum at 23:00 h. In vitro HD and HMT activities were also found to have 24-h rhythms with peak activites in both occurring at 04:00 h. HMT also had a broad secondary peak throughout the day, whereas HD activity during the day was dominated by a mid-light trough at 16:00 h. These rhythms are considered significant for evaluation of the control and physiological role of histamine in the mammalian hypothalamus.

Animals↗