Chick pineal serotonin acetyltransferase: a diurnal cycle maintained in vitro and its regulation by light

S. D. Wainwright; Lillian K. Wainwright

doi:10.1139/o79-088

Chick pineal serotonin acetyltransferase: a diurnal cycle maintained in vitro and its regulation by light

Canadian Journal of Biochemistry ◽

10.1139/o79-088 ◽

1979 ◽

Vol 57 (6) ◽

pp. 700-709 ◽

Cited By ~ 54

Author(s):

S. D. Wainwright ◽

Lillian K. Wainwright

Keyword(s):

Enzyme Activity ◽

Diurnal Cycle ◽

Prolonged Exposure ◽

Continuous Illumination ◽

Constant Darkness ◽

Light Cycle ◽

Acetyltransferase Activity ◽

Lighting Conditions

We have reproduced in vitro the diurnal cycles in levels of serotonin acetyltransferase activity found in the chick pineal gland in vivo. The more closely the lighting conditions of culture matched those under which the birds were raised, the closer was the similarity between cycles in levels of enzyme activity in vitro and in vivo. Repetitive cycles in levels of acetyltransferase activity persisted in culture for at least 4 days under a diurnal cycle of illumination, and at least 2 days in continuous darkness. When glands were explanted into culture in the light phase of a cycle, short periods of further exposure to light markedly stimulated subsequent increase of acetyltransferase in the dark (after a short lag). Prolonged exposure to light in culture markedly inhibited increase of enzyme activity. Cycles in the levels of enzyme activity in glands cultured under altered light cycles were regulated primarily by changes in illumination. However, the endogenous biological 'clock' remained at least partly entrained to the original light cycle. Increase of acetyltransferase activity in vitro was markedly stimulated by theophylline plus compound Ro. 20.1724 (4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone) under all lighting conditions. Kinetics (to the time of attaining maximum levels in situ) of the increase under diurnal lighting and in constant darkness were indistinguishable from those in vivo. A high concentration of dl-propranolol markedly stimulated an increase in acetyltransferase activity in glands cultured in constant darkness but had little effect on glands under diurnal lighting or continuous illumination.

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Adrenergic control of pineal N-acetyltransferase activity: developmental aspects.

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1977.233.3.e141 ◽

1977 ◽

Vol 233 (3) ◽

pp. E141

Author(s):

A Yuwiler ◽

D C Klein ◽

M Buda ◽

J L Weller

Keyword(s):

Enzyme Activity ◽

Adrenergic Receptors ◽

Neonatal Rat ◽

Adrenergic Stimulation ◽

Catecholamine Synthesis ◽

Acetyltransferase Activity ◽

Presynaptic Mechanisms ◽

Adrenergic Control

The activity of pineal N-acetyltransferase in the neonatal rat does not exhibit the large daily rhythm seen in the adult and is intermediate between the low day and high night adult values. These intermediate values appear to result from adrenergic stimulation. Blockade of adrenergic receptors or of catecholamine synthesis results in a decrease in enzyme activity in vivo. In vitro studies provide additional evidence of a completely developed postsynaptic adrenergic control system for pineal N-acetyltransferase activity at birth. Our observations indicate that the appearance of a circadian rhythm in pineal N-acetyltransferase at the end of the first week of life reflects the development of presynaptic mechanisms and structures necessary for the control of catecholamine release and uptake. These events follow the developmental appearance of the postsynaptic mechanisms required to mediate the adrenergic-cycle AMP regulation of pineal N-acetyltransferase activity, which can be detected prior to birth.

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Regulation of the diurnal cycle in activity of serotonin acetyltransferase in the chick pineal gland

Canadian Journal of Biochemistry ◽

10.1139/o78-102 ◽

1978 ◽

Vol 56 (7) ◽

pp. 685-690 ◽

Cited By ~ 7

Author(s):

S. D. Wainwright ◽

Lillian K. Wainwright

Keyword(s):

Enzyme Activity ◽

Organ Culture ◽

Pineal Gland ◽

Diurnal Cycle ◽

Adenosine Receptor ◽

Control Mechanism ◽

Negative Control ◽

Acetyltransferase Activity ◽

In Vivo Effects

When chick pineal glands were explanted into organ culture at midlight phase of a diurnal cycle of illumination and incubated in the dark, they developed marked increases in serotonin acetyltransferase (acetyl coA:arylamine N-acetyltransferase; EC 2.3.1.5) activity. Either this increase in activity was inhibited or its onset was retarded in glands incubated under constant illumination.Supplements of theophylline, isobutylmethylxanthine, quinidine, and compound Ro 20-1724 (4-(3-butoxyl-4-methoxybenzyl)-2-imidazolidinone) elicited very marked increases in serotonin acetyltransferase activity in glands cultured in the dark. Levels of activity attained after 6 h in culture approached or exceeded the maximum levels attained at middark phase of the diurnal cycle in vivo. Effects of theophylline and compound Ro 20-1724 were additive.Supplements of dibutryl cAMP had little or no effect upon levels of serotonin acetyltransferase activity when tested alone or in combination with theophylline but further enhanced the increase in the level of enzyme activity elicited by Ro 20-1724. Adenosine and cAMP had little or no effect upon levels of serotonin acetyltransferase activity.It is concluded that levels of serotonin acetyltransferase activity in the chick pineal gland are regulated by a repressive, negative-control mechanism, which probably involves a membranous adenosine receptor.

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The relationship between variations in levels of serotonin acetyltransferase activity and cGMP content in cultured chick pineal glands

Canadian Journal of Biochemistry ◽

10.1139/o81-082 ◽

1981 ◽

Vol 59 (8) ◽

pp. 593-601 ◽

Cited By ~ 13

Author(s):

S. D. Wainwright ◽

Lillian K. Wainwright

Keyword(s):

Enzyme Activity ◽

Circadian Rhythm ◽

Cyclic Amp ◽

Diurnal Cycle ◽

Constant Darkness ◽

Continuous Darkness ◽

Camp Content ◽

Lighting Conditions ◽

Subsequent Loss ◽

The Relationship

Chick pineal glands cultured in continuous darkness exhibited a circadian rhythm in 3′,5′-cyclic GMP (cGMP) content. cGMP content increased earlier and fell later than in glands incubated under diurnal lighting. A "spike" of further increase in cGMP content preceded start of decline in acetyl-CoA:arylamine N-acetyltransferase (NAT) activity.Theophylline or 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (compound Ro 20.1724) alone markedly stimulated increase of NAT activity in the dark, and retarded subsequent loss of activity either in the dark or in the photoperiod of a diurnal cycle of illumination. In constant darkness a combination of the two agents elicited greater increases of NAT than either alone and suppressed subsequent loss of activity for several hours. Under diurnal lighting conditions the combination was only slightly more effective than either alone. Compound Ro 20.1724 suppressed the precipitous loss of NAT activity seen when glands are transferred prematurely to the light. However, neither the rate or extent of loss of activity was greatly affected by theophylline.Effects of theophylline and compound Ro 20.1724 upon levels of NAT activity appeared to be due primarily to effects upon the process(es) by which enzyme activity is lost. They could not be attributed solely to effects upon pineal contents of cGMP and (or) 3',5'-cyclic AMP (cAMP). Theophylline alone was as effective as the drug combination in eliciting and maintaining elevated pineal content of cGMP, but had little effect upon cAMP content. Compound Ro 20.1724 alone elicited large increases in pineal contents of both nucleotides but did not sustain them.

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Effects of Changes in Environmental Lighting Upon Levels of Hydroxyindole O-Methyltransferase Activity in the Developing-Chick Pineal Gland

Canadian Journal of Biochemistry ◽

10.1139/o75-060 ◽

1975 ◽

Vol 53 (4) ◽

pp. 438-443 ◽

Cited By ~ 9

Author(s):

S. D. Wainwright

Keyword(s):

Enzyme Activity ◽

Pineal Gland ◽

Diurnal Cycle ◽

Enzymic Activity ◽

Constant Light ◽

Constant Darkness ◽

Methyltransferase Activity ◽

Constant Illumination ◽

Lighting Conditions ◽

Environmental Lighting

The level of hydroxyindole O-methyltransferase (HIOMT) activity in the pineal gland of developing chicks raised under constant illumination rose more rapidly and to higher values than in the gland of birds maintained in constant darkness. Rates of net increase in activity, and levels of activity attained, for birds raised under a diurnal cycle of illumination were intermediate between those maintained in constant light or darkness. Under each of the lighting conditions, the course of increase in enzymic activity was markedly affected by variations in an unidentified factor, the source of which appeared to be the hatching eggs.Birds transferred from constant light to the dark showed either an arrest of increase in enzyme activity or a loss of activity until the level equalled that observed for chicks of the same age raised in constant darkness. Chicks transferred from constant darkness to constant illumination showed marked increases in levels of enzyme activity at rates comparable with the maximal values observed with birds maintained under constant illumination, regardless of age and without delay. No diurnal cycle in level of HIOMT activity was observed in the pineals of 15-day birds.

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Effects of Hyperglycemia on Vascular Smooth Muscle Ca2+Signaling

BioMed Research International ◽

10.1155/2017/3691349 ◽

2017 ◽

Vol 2017 ◽

pp. 1-16 ◽

Cited By ~ 6

Author(s):

Nahed El-Najjar ◽

Rashmi P. Kulkarni ◽

Nancy Nader ◽

Rawad Hodeify ◽

Khaled Machaca

Keyword(s):

Insulin Resistance ◽

Smooth Muscle ◽

Sarcoplasmic Reticulum ◽

Vascular Smooth Muscle ◽

Complex Disease ◽

Prolonged Exposure ◽

In Vitro System ◽

A7r5 Cells

Diabetes is a complex disease that is characterized with hyperglycemia, dyslipidemia, and insulin resistance. These pathologies are associated with significant cardiovascular implications that affect both the macro- and microvasculature. It is therefore important to understand the effects of various pathologies associated with diabetes on the vasculature. Here we directly test the effects of hyperglycemia on vascular smooth muscle (VSM) Ca2+signaling in an isolated in vitro system using the A7r5 rat aortic cell line as a model. We find that prolonged exposure of A7r5 cells to hyperglycemia (weeks) is associated with changes to Ca2+signaling, including most prominently an inhibition of the passive ER Ca2+leak and the sarcoplasmic reticulum Ca2+-ATPase (SERCA). To translate these findings to the in vivo condition, we used primary VSM cells from normal and diabetic subjects and find that only the inhibition of the ER Ca2+leaks replicates in cells from diabetic donors. These results show that prolonged hyperglycemia in isolation alters the Ca2+signaling machinery in VSM cells. However, these alterations are not readily translatable to the whole organism situation where alterations to the Ca2+signaling machinery are different.

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Metabolic importance of Na+/K+-ATPase activity during sea urchin development.

Journal of Experimental Biology ◽

10.1242/jeb.200.22.2881 ◽

1997 ◽

Vol 200 (22) ◽

pp. 2881-2892 ◽

Cited By ~ 3

Author(s):

P Leong ◽

D Manahan

Keyword(s):

Enzyme Activity ◽

Atpase Activity ◽

Sea Urchin ◽

Sodium Pump ◽

Sea Water ◽

Strongylocentrotus Purpuratus ◽

Lytechinus Pictus ◽

Stimulation Of

Early stages of animal development have high mass-specific rates of metabolism. The biochemical processes that establish metabolic rate and how these processes change during development are not understood. In this study, changes in Na+/K+-ATPase activity (the sodium pump) and rate of oxygen consumption were measured during embryonic and early larval development for two species of sea urchin, Strongylocentrotus purpuratus and Lytechinus pictus. Total (in vitro) Na+/K+-ATPase activity increased during development and could potentially account for up to 77 % of larval oxygen consumption in Strongylocentrotus purpuratus (pluteus stage) and 80 % in Lytechinus pictus (prism stage). The critical issue was addressed of what percentage of total enzyme activity is physiologically active in living embryos and larvae and thus what percentage of metabolism is established by the activity of the sodium pump during development. Early developmental stages of sea urchins are ideal for understanding the in vivo metabolic importance of Na+/K+-ATPase because of their small size and high permeability to radioactive tracers (86Rb+) added to sea water. A comparison of total and in vivo Na+/K+-ATPase activities revealed that approximately half of the total activity was utilized in vivo. The remainder represented a functionally active reserve that was subject to regulation, as verified by stimulation of in vivo Na+/K+-ATPase activity in the presence of the ionophore monensin. In the presence of monensin, in vivo Na+/K+-ATPase activities in embryos of S. purpuratus increased to 94 % of the maximum enzyme activity measured in vitro. Stimulation of in vivo Na+/K+-ATPase activity was also observed in the presence of dissolved alanine, presumably due to the requirement to remove the additional intracellular Na+ that was cotransported with alanine from sea water. The metabolic cost of maintaining the ionic balance was found to be high, with this process alone accounting for 40 % of the metabolic rate of sea urchin larvae (based on the measured fraction of total Na+/K+-ATPase that is physiologically active in larvae of S. purpuratus). Ontogenetic changes in pump activity and environmentally induced regulation of reserve Na+/K+-ATPase activity are important factors that determine a major proportion of the metabolic costs of sea urchin development.

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Anti-Diabetic Retinopathy Potential of Noni: The beneficial effect and possible mechanism

Diabetes and Islet Biology ◽

10.31579/2641-8975/021 ◽

2020 ◽

Vol 3 (1) ◽

pp. 01-21

Author(s):

Faisal Ali

Keyword(s):

Diabetic Retinopathy ◽

Prolonged Exposure ◽

Morinda Citrifolia ◽

In Vivo Studies ◽

Laboratory Research ◽

Tropical Region ◽

Bioactive Substances ◽

High Blood Glucose

Noni (Morinda citrifolia L.) is being evaluated in laboratory research for its benefits as an antioxidant and immunity booster, as well as for its properties to prevent tumors and cure diabetes. The vast spread of Noni in tropical region of the globe, from America reaching to Africa and Southeast Asia, contributed in enhancing its usage and potency due to the diversity in harvest zone. Noni parts comprise fruits, seeds, leaves, and flowers are being used for individual nutritional and therapeutical values. Nevertheless, the fruit is widely characterized to contain the most valuable bioactive substances. On the other hand, diabetic retinopathy (DR) is a microvascular disorder impacting the small blood vessels in the retina, which includes microaneurysms, retinal hemorrhages, and hard exudates results from prolonged exposure to high blood glucose levels. The anti-diabetes effect of Noni extract and juice has been examined but the beneficial role of Noni and its potential mechanisms against the development of diabetic retinopathy phenotype is still ambiguous. This review, therefore, will discusses in details the pharmacological actions of M. citrifolia fruit, along with their isolated phytochemical compounds on diabetic retinopathy markers, through describing the conducted in vitro and in vivo studies as well as clinical data.

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Abstract 585: Endothelial Cells from Adipose Tissue of Obese Humans Display Mesenchymal Characteristics

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.585 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Bronson A Haynes ◽

Eric J Lehrer ◽

Giann J Bhatt ◽

Ryan W Huyck ◽

Ashley N James ◽

...

Keyword(s):

Endothelial Cells ◽

Adipose Tissue ◽

Prolonged Exposure ◽

Endothelial Permeability ◽

Fold Increase ◽

Atp Production ◽

Functional Changes ◽

Twist 1

The mechanisms underlying vascular dysfunction in adipose tissue (AT) in obesity are not clearly understood. Our hypothesis is that in response to pro-inflammatory cytokines (PIC) present in obese AT, endothelial cells (EC) can de-differentiate and acquire a mesenchymal-like phenotype (EndoMT) that leads to endothelial dysfunction. To test our hypothesis, we measured endothelial and mesenchymal markers of CD31 + CD34 + EC isolated from omental (OM) and subcutaneous (SC) AT of bariatric subjects (BAMVEC) using RT-PCR and western blot. Permeability and oxidative metabolism were determined by ECIS and Seahorse analyzer XF e 24, respectively. BAMVEC isolated from both OM and SC fat showed very low protein expression of vWF and VE-Cadherin (EC markers) and abundantly expressed αSMA and the EMT transcription factor twist-1. To determine effects of PIC on EndoMT, commercially available primary endothelial cells from AT (HAMVEC) were treated in vitro with PIC (2.5ng/mL TNFα, IFNγ and TGFβ) for 1, 3 or 6 days. We found progressive down-regulation by >2-fold (p<0.001) of the EC markers vWF, VE-Cadherin, and Occludin compared to controls. As early as 1 day of PIC treatment twist-1 (p<0.001) and snail1 (p<0.05) showed an increase by >2-fold. Similarly, OM and SC BAMVEC expressed >2-fold increase in the mesenchymal genes twist-1, FSP1, αSMA, and snail1 compared to untreated HAMVEC. Metabolically, BAMVEC had increased ATP production and maximal respiration compared to HAMVEC suggesting increased oxidative phosphorylation, a marker of mesenchymal-like cells. PIC stimulation of HAMVEC yielded significant increases in endothelial permeability and motility (p<0.001). Notably, there were no significant differences in any of the markers between OM and SC BAMVEC. These results show that EC in obese AT exhibit a mesenchymal-like phenotype which may account for functional changes such as increased permeability and migration and are not depot specific. Using primary EC from human AT we showed that prolonged exposure to PIC induces a phenotype similar to CD31+CD34+ EC from obese AT. This supports the concept that AT inflammation can promote EC de-differentiation in vivo and our in vitro model is suitable for future studies to uncover the relevant mechanisms.

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Hereditary Nonspherocytic Hemolysis With Erythrocyte Phosphofructokinase Deficiency

Blood ◽

10.1182/blood.v39.3.415.415 ◽

1972 ◽

Vol 39 (3) ◽

pp. 415-425 ◽

Cited By ~ 25

Author(s):

Larry Waterbury ◽

Eugene P. Frenkel

Keyword(s):

Enzyme Activity ◽

Adenosine Triphosphate ◽

Lactate Production ◽

Kinetic Studies ◽

Glycogen Storage ◽

Muscle Disease ◽

Phosphofructokinase Activity ◽

Phosphofructokinase Deficiency

Abstract Hereditary nonspherocytic hemolysis associated with abnormal erythrocyte phosphofructokinase activity was demonstrated in a young man. Enzyme activity in the propositus, his mother, and maternal grandmother was approximately 60% of normal controls. There was markedly increased lability of enzyme activity on in vitro storage. Kinetic studies revealed increased sensitivity to adenosine triphosphate inhibition. Erythrocyte adenosine triphosphate levels were depressed. The absence of muscle disease and the presence of normal in vivo lactate production following ischemic exercise differentiated this kindred from those with Type VII glycogen storage disease.

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