Acute stressors increase plasma corticosterone and decrease locomotor activity in a terrestrial salamander (Desmognathus ochrophaeus)

Three biological rhythms (locomotor activity, body temperature, and plasma corticosterone) were measured simultaneously in individual rats under light-dark cycles and continuous light. Spontaneous locomotor activity was recorded on an Animex and body temperature was telemetrically monitored throughout the experiments. Blood samples were obtained serially at 2-h intervals on the experimental days. Phase angles of these rhythms were calculated by a least-squares spectrum analysis. Under light-dark cycles, the acrophases of locomotor activity, body temperature, and plasma corticosterone were found at 0029, 0106, and 1940 h, respectively. When rats were exposed to 200 lx continuous light, locomotor activity and body temperature showed free-running rhythms with a period of 25.2 h on the average. Plasma corticosterone levels determined at 12 days after exposure to continuous light exhibited a circadian rhythm with the acrophase shifted to 0720. The acrophases of locomotor activity and body temperature, determined simultaneously on the same day, were found to be located at 1303 and 1358 h, respectively. Phase-angle differences among the three rhythms on the 12th day of continuous light were essentially the same with those under the light-dark cycle. These results suggest that circadian rhythms of locomotor activity, body temperature, and plasma corticosterone are most probably coupled to a common internal oscillator in the rat.

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Dissociation of circadian rhythms in rats with a hypothalamic island

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1984.246.6.r949 ◽

1984 ◽

Vol 246 (6) ◽

pp. R949-R954

Author(s):

S. Honma ◽

K. Honma ◽

T. Hiroshige

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Circadian Rhythm ◽

Locomotor Activity ◽

Corticosterone Level ◽

Direct Consequence ◽

Plasma Corticosterone ◽

Spontaneous Locomotor Activity ◽

Medial Basal Hypothalamus ◽

The Central Nervous System

Complete isolation of the medial basal hypothalamus, including the suprachiasmatic nuclei in the isolated island, from the rest of the central nervous system was performed in rats. The circadian rhythm of plasma corticosterone level remained essentially intact in 5 of 16 rats with complete islands, whereas that of spontaneous locomotor activity was decomposed into ultradian bursts in 15 rats, resulting in a clear dissociation of the two rhythms in four rats. One rat, whose circadian rhythm of both variables persisted after the hypothalamic isolation, showed a diurnal activity. The 24-h patterns of plasma corticosterone of the other rats could be characterized as either episodic or continuously low throughout the day. A prefeeding corticosterone peak was detected under restricted feeding in rats with episodic fluctuations but not in those with continuously low hormone levels. It is concluded that the hypothalamic island includes the fundamental structures necessary for the manifestation of the entrained circadian rhythm of plasma corticosterone in rats under ad libitum feeding, whereas it contains only a part of that for spontaneous locomotor activity. The coupling pathways from the circadian oscillator(s) to these overt rhythms seem to be separate in the central nervous system, and the circadian rhythm of plasma corticosterone is not a direct consequence of that of locomotor activity.

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Ethosecretogram: relation of behavior to plasma corticosterone in freely moving rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1984.247.1.r40 ◽

1984 ◽

Vol 247 (1) ◽

pp. R40-R45 ◽

Cited By ~ 1

Author(s):

I. Shiraishi ◽

K. Honma ◽

S. Honma ◽

T. Hiroshige

Keyword(s):

Locomotor Activity ◽

Animal Behavior ◽

Corticosterone Level ◽

Plasma Corticosterone ◽

Male Rats ◽

Conscious Rats ◽

Series Of Experiments ◽

Freely Moving ◽

The Right ◽

Temporally Correlated

An ethosecretogram, which illustrates the phase relation between animal behavior and plasma hormone levels, was constructed in conscious rats. A catheter was placed into the right atrium in male rats 2 days before blood sampling. Plasma corticosterone levels were monitored individually through the catheter every 5 min over a period of several hours under freely moving conditions on an Animex, which records spontaneous locomotor activity. The results showed that the bursts of locomotor activity were temporally correlated with those of plasma corticosterone level, the peak of the former preceding the hormone peak by 15 min. Regarding the type of locomotor activity, feeding and grooming were significantly correlated with the subsequent hormone elevation, whereas drinking was not. In a separate series of experiments, effects of feeding and drinking on plasma corticosterone levels were examined in conscious rats that had been fasted or water deprived for 24 or 48 h. In both cases, feeding induced a more pronounced elevation than drinking, although locomotor activity counts per se increased more sharply in the latter. It is concluded that in the ethosecretogram specific types of locomotor activity such as feeding and grooming induce a phase-locked elevation of plasma corticosterone under freely moving conditions.

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CIRCADIAN RHYTHMS OF PLASMA CORTICOSTERONE BINDING ACTIVITY IN THE RAT AND THE MOUSE

Acta Endocrinologica ◽

10.1530/acta.0.0910150 ◽

1979 ◽

Vol 91 (1) ◽

pp. 150-157 ◽

Cited By ~ 32

Author(s):

John E. Ottenweller ◽

Albert H. Meier ◽

Albert C. Russo ◽

Marie E. Frenzke

Keyword(s):

Locomotor Activity ◽

Circadian Rhythms ◽

Protein Binding ◽

Peak Level ◽

Plasma Corticosterone ◽

Binding Activity ◽

Plasma Samples ◽

Late Afternoon ◽

Competitive Protein Binding ◽

Rats And Mice

ABSTRACT Corticosterone binding activity (CBA) and corticosteroids were measured by competitive protein binding techniques in plasma samples drawn from rats and mice at different times of day. Circadian rhythms of plasma CBA were found in both rats (onset of 14-h daily photoperiod: 0600) and mice (onset of 14-h daily photoperiod: 0700). The plasma CBA rhythm was bimodal in rats with peaks at 1000 and 1800 and unimodal in mice with peak level from 0100 to 0500. Circadian rhythms of plasma corticosteroid concentration with peaks during the late afternoon were confirmed in both rats and mice. The plasma CBA rhythms appear to be related to the circadian rhythms of both locomotor activity and plasma corticosteroid concentration.

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Long-term effects of pre-pubertal fluoxetine on behaviour and monoaminergic stress response in stress-sensitive rats

Acta Neuropsychiatrica ◽

10.1017/neu.2016.53 ◽

2016 ◽

Vol 29 (4) ◽

pp. 222-235 ◽

Cited By ~ 6

Author(s):

Nico Johan Badenhorst ◽

Linda Brand ◽

Brian Herbert Harvey ◽

Susanna Maria Ellis ◽

Christiaan Beyers Brink

Keyword(s):

Locomotor Activity ◽

Stress Responses ◽

Forced Swim Test ◽

Early Adulthood ◽

Plasma Corticosterone ◽

Long Term Effects ◽

Swim Stress ◽

Term Outcome ◽

Long Term Outcome

ObjectiveAlthough prescription rates of antidepressants for children and adolescents have increased, concerns have been raised regarding effects on neurodevelopment and long-term outcome. Using a genetic animal model of depression, this study investigated the long-term effects of pre-pubertal administration of fluoxetine (FLX) on depressive-like behaviour in early adulthood, as well as on central monoaminergic response to an acute stressor. We postulated that pre-pubertal FLX will have lasting effects on animal behaviour and monoaminergic stress responses in early adulthood.MethodsFlinders sensitive line (FSL) rats received 10 mg/kg/day FLX subcutaneously from postnatal day 21 (PnD21) to PnD34 (pre-pubertal). Thereafter, following normal housing, rats were either subjected to locomotor testing and the forced swim test (FST) on PnD60 (early adulthood), or underwent surgery for microdialysis, followed on PnD60 by exposure to acute swim stress and measurement of stressor-induced changes in plasma corticosterone and pre-frontal cortical monoamine concentrations.ResultsPre-pubertal FLX did not induce a late emergent effect on immobility in FSL rats on PnD60, whereas locomotor activity was significantly decreased. Acute swim stress on PnD60 significantly increased plasma corticosterone levels, and increased pre-frontal cortical norepinephrine (NE) and 5-hydroxyindole-3-acetic acid (5-HIAA) concentrations. Pre-pubertal FLX significantly blunted the pre-frontal cortical NE and 5-HIAA response following swim stress on PnD60. Baseline dopamine levels were significantly enhanced by pre-pubertal FLX, but no further changes were induced by swim stress.ConclusionPre-pubertal FLX did not have lasting antidepressant-like behavioural effects in genetically susceptible, stress-sensitive FSL rats. However, such treatment reduced locomotor activity, abrogated noradrenergic and serotonergic stressor responses and elevated dopaminergic baseline levels in adulthood.

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TEMPORAL RELATIONSHIPS BETWEEN THE DIURNAL RHYTHM OF HYPOTHALAMIC CORTICOTROPHIN RELEASING FACTOR, PITUITARY CORTICOTROPHIN AND PLASMA CORTICOSTERONE IN THE RAT

Journal of Endocrinology ◽

10.1677/joe.0.0720113 ◽

1977 ◽

Vol 72 (2) ◽

pp. 113-120 ◽

Cited By ~ 40

Author(s):

GUY IXART ◽

ALAIN SZAFARCZYK ◽

JEAN-LUC BELUGOU ◽

IVAN ASSENMACHER

Keyword(s):

Locomotor Activity ◽

Extreme Values ◽

Plasma Corticosterone ◽

Female Rats ◽

Pituitary Cells ◽

Adrenal Cells ◽

Corticotrophin Releasing Factor ◽

Temporal Relationships ◽

Central Origin ◽

Phase Relationships

SUMMARY Plasma corticosterone (fluorometric assay), pituitary ACTH (bioassay using isolated adrenal cells) and hypothalamic corticotrophin releasing factor (CRF) (bioassay using isolated pituitary cells) were measured singly in groups of six female rats which were killed at 11.00, 15.00, 19.00, 21.00, 23.00, 01.00, 03.00, 05.00, 07.00 and 11.00 h, after 5 weeks of adaptation to a photoperiod of 12 h light:12 h darkness. Locomotor activity was recorded continuously, using actographic cages, and the waking/sleep pattern was recorded by electroencephalography from chronically implanted control rats during the first hours of the light span. The three hormones measured fluctuated with a 24 h rhythmicity, with extreme values ranging between 4·12 ± 1·42 and 31·78 ± 194 (s.e.m.) μg/100 ml for corticosterone, 4486 ± 269 and 16629 ± 882μu./mg pituitary for ACTH, and 439 ± 20 and 1270 ± 39μu. ACTH production/hypothalamus/105 pituitary cells. The onset of the ascending phase of the rhythm started during the first 2 h of light for CRF, 2 h later for ACTH, and again 2 h later for corticosterone. Similarly, the estimated acrophase of the rhythms occurred respectively, 9·4 (CRF), 10·3 (ACTH) and 14·4 h (corticosterone) after onset of light. These phase relationships point to a central origin of the adrenal rhythm. The diurnal activation of CRF at the very beginning of the light phase was concomitant with an almost immediate reduction of the locomotor activity and onset of sleep. These correlations favour the hypothesis of a common temporal control of both the adrenal and the sleep/waking rhythms.

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