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

1981 ◽  
Vol 59 (8) ◽  
pp. 593-601 ◽  
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.

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

1979 ◽  
Vol 57 (6) ◽  
pp. 700-709 ◽  
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.

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

1975 ◽  
Vol 53 (4) ◽  
pp. 438-443 ◽  
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.

Manifestation of circadian rhythm under constant light depends on lighting conditions during lactation

1997 ◽  
Vol 272 (4) ◽  
pp. R1039-R1046 ◽  
Author(s):  
T. Cambras ◽  
M. M. Canal ◽  
A. Torres ◽  
J. Vilaplana ◽  
A. Diez-Noguera
Keyword(s):  
Circadian Rhythm ◽  
Motor Activity ◽  
Activity Rhythm ◽  
Bright Light ◽  
Constant Light ◽  
Continuous Illumination ◽  
Continuous Darkness ◽  
Adult Rats ◽  
Lighting Conditions ◽  
Variance Explained

Adult rats transferred to continuous illumination (LL) show a disruption of circadian rhythms, although the mechanisms underlying this effect are not yet well known. In previous experiments, we found that when rats were born and raised under LL they showed an ultradian pattern during the first 10 days after weaning, but afterward they generated a circadian rhythm that was maintained until adulthood. It was not clear whether this evolution was attributable to the influence of the rhythm of the mother or to the effect of constant light. Here, we have studied the motor activity rhythm of young rats maintained under LL after weaning, taking into account the conditions to which they were exposed during lactation [LL or continuous darkness (DD)]. To check the possible effect of the rhythm of the dam, on the day of delivery some of the dams were blinded, others were subjected to a restricted feeding schedule of 3 h/day, and the others were used as controls. For each rat, the period of the circadian rhythm and the percentage of variance explained by this rhythm were calculated. Results show that all rats maintained under LL during lactation expressed a circadian rhythm in their motor activity. However, rats maintained under DD during lactation did not. This effect did not seem to be dependent on the type of dam. These results suggest that the rhythm of the dams does not affect the manifestation of the rhythm of the pups and that the expression of circadian rhythmicity under constant bright light depends on the lighting conditions under which the animals were maintained during lactation, which could affect the development of the circadian pacemaker or the retina.

scholarly journals Dunce mutants of Drosophila melanogaster: mutants defective in the cyclic AMP phosphodiesterase enzyme system.

1981 ◽  
Vol 90 (1) ◽  
pp. 101-107 ◽  
Author(s):  
R L Davis ◽  
J A Kiger
Keyword(s):  
Enzyme Activity ◽  
Drosophila Melanogaster ◽  
Cyclic Amp ◽  
Enzyme System ◽  
Residual Enzyme Activity ◽  
Wild Type ◽  
Camp Content ◽  
Mutant Strains ◽  
Normal Enzyme ◽  
Type Strains

The cyclic AMP and cyclic GMP phosphodiesterase activities present in flies of six mutant strains of the dunce gene and in the parent wild-type strains are characterized. All of the mutants exhibit aberrant cyclic AMP metabolism. The mutant strains dunceM14, dunceM11, and dunceML appear to be amorphic, because they completely lack the cAMP-specific phosphodiesterase normally present in adult flies. These strains exhibit extremely high levels of cAMP. The mutant strains dunce1, dunce2, and dunceCK are hypomorphic and exhibit reduced levels of the cAMP-specific phosphodiesterase. These strains exhibit less marked increases in cAMP content compared with the three amorphic strains. The dunce2 strain possesses a residual enzyme activity that exhibits anomalous kinetics compared with those of the normal enzyme. The possibility that the dunce locus is the structural gene for the cAMP-specific phosphodiesterase is discussed.

scholarly journals Learning and Working Memory In Mice Under Different Lighting Conditions

2013 ◽  
Vol 21 (3) ◽  
pp. 349-355
Author(s):  
Shayenne Elizianne Ramos ◽  
Luis David Solis Murgas ◽  
Monica Rodrigues Ferreira ◽  
Carlos Alberto Mourao Junior
Keyword(s):  
Working Memory ◽  
Object Recognition ◽  
Recognition Task ◽  
Constant Darkness ◽  
Behavioral Tests ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Object Recognition Task ◽  
Swiss Mice ◽  
Lighting Conditions

Objective. This study aimed to investigate the effect of different light/ dark cycles and light intensity during behavioral tests of learning and working memory in Swiss mice. Method. Fifty-seven Swiss mice were kept in a housing room in either a 12:12h light/dark cycle (LD), con­stant light (LL), or constant darkness (DD). The animals were then tested in Lashley maze and Object recognition task under either 500 or 0 lux illumination, resulting in six treatments (LD-500, LD-0, LL- 500, LL-0, DD-500, and DD-0). Results. There were no significant differences between the conditions of light/dark, or between tests at 500 and 0 lux. Animals kept in constant darkness and tested at 0 lux (DD-0) had learning and working memory impaired, as demon­strated by slower learning in Lashley III maze, and no object recogni­tion in Object recognition task. Conclusion. Continuous darkness throughout the experiment affected the learning and working mem­ory of Swiss mice.

scholarly journals Circadian Blood Pressure Rhythm in Cardiovascular and Renal Health and Disease

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 868
Author(s):  
Jiayang Zhang ◽  
Ruoyu Sun ◽  
Tingting Jiang ◽  
Guangrui Yang ◽  
Lihong Chen
Keyword(s):  
Blood Pressure ◽  
Circadian Rhythm ◽  
Molecular Mechanisms ◽  
Current Understanding ◽  
Renal Outcomes ◽  
Circadian Blood Pressure ◽  
Health And Disease ◽  
The Relationship

Blood pressure (BP) follows a circadian rhythm, it increases on waking in the morning and decreases during sleeping at night. Disruption of the circadian BP rhythm has been reported to be associated with worsened cardiovascular and renal outcomes, however the underlying molecular mechanisms are still not clear. In this review, we briefly summarized the current understanding of the circadian BP regulation and provided therapeutic overview of the relationship between circadian BP rhythm and cardiovascular and renal health and disease.

Influence of Enzyme Activity of Bacteria and Leucocytes in Raw Milk on Age Gelation after UHT Processing

1984 ◽  
Vol 47 (2) ◽  
pp. 105-107 ◽  
Author(s):  
BARBARA P. KEOGH ◽  
G. PETTINGILL
Keyword(s):  
Enzyme Activity ◽  
High Temperature ◽  
Inhibitory Action ◽  
Raw Milk ◽  
Bacterial Counts ◽  
High Temperature Processing ◽  
The Relationship ◽  
Ultra High Temperature

An investigation was undertaken into the relationship between the enzyme activity of cells harvested from raw milk and time taken for age gelation (TAG) to occur in the milk after ultra-high-temperature processing. It was shown that there was no relationship between the TAG and the bacterial counts on milk agar at 30°C or 7°C nor was there a relationship between the counts and the level of enzyme activity of the harvested cells. There was, however, a significant correlation between the level of enzyme activity of the harvested cells and the TAG. When extra bovine leucocytes were added to raw milk before processing, the TAG was increased. This suggested that there was an inhibitory action of leucocytes in development of age gelation.

The Relationship of the −5, −8, and −24 Variant Alleles in African Americans to Triosephosphate Isomerase (TPI) Enzyme Activity and to TPI Deficiency

Blood ◽  
1998 ◽  
Vol 92 (8) ◽  
pp. 2959-2962 ◽  
Author(s):  
Arthur Schneider ◽  
Linda Forman ◽  
Beryl Westwood ◽  
Catherine Yim ◽  
James Lin ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
African American ◽  
African Americans ◽  
Triosephosphate Isomerase ◽  
Small Subset ◽  
Nucleotide Substitutions ◽  
Severe Deficiency ◽  
American Society ◽  
Relationship Of ◽  
The Relationship

Abstract In 424 African-American and 75 white subjects, we found that the −5 (TPI 592 A→G), −8 (TPI 589 G→A), and −24 (TPI 573 T→G) variants in the triosephosphate isomerase (TPI) gene occurred frequently (41.0%) in the African-American subjects but did not occur in the whites. These data suggest that this set of polymorphisms may turn out to be one of the higher-incidence molecular markers of African lineage, a surprising finding because others had reported that these nucleotide substitutions were restricted to a small subset of African Americans who had been characterized as TPI-deficiency heterozygotes. Additionally, we investigated the relationship of these variants to TPI-enzyme activity. Although the variant substitutions (occurring in three haplotypes: −5 alone, −5 −8, and −5 −8 −24) were associated with moderate reduction in enzyme activity, severe-deficiency heterozygotes could not be identified with certainty, and none of the haplotypes were restricted to subjects with marked reduction of enzyme activity. Three subjects were homozygous for the −5 −8 haplotype, a finding inconsistent with the putative role of this haplotype as the cause of a null variant incompatible with life in homozygotes. Despite these findings, the possibility remains that the −5 −8 or −5 −8 −24 haplotypes may in some instances contribute to compound heterozygosity and clinical TPI deficiency. © 1998 by The American Society of Hematology.

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