Diurnal Variation in Adrenal Cortical Function

Nichols, C.; Tyler, Frank H.

doi:10.1146/annurev.me.18.020167.001525

Cited by 51 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additional screening of potential modulators identified the melanocortin peptide adrenocorticotropic hormone (ACTH) as a candidate modulator of EOD and electrocyte AP waveform. ACTH is released by the action of 5-HT in the hypothalamus and pituitary (Brown, 1994), and its levels in circulation show a pronounced circadian rhythm (Nichols and Tyler, 1967). Circulating ACTH levels also are elevated by stress (for review, see Sapolsky, 2002) and social encounters (Lyons et al, 1995;Hoglund et al, 2000), consistent with our findings that stressors and social encounters modulate the EOD within minutes (Franchina et al, 2001;Stoddard et al, 2003).…”

Section: Introductionsupporting

confidence: 86%

Adrenocorticotropic Hormone Enhances the Masculinity of an Electric Communication Signal by Modulating the Waveform and Timing of Action Potentials within Individual Cells

Markham

Stoddard²

2005

J. Neurosci.

View full text Add to dashboard Cite

We report here that melanocortin peptides appear to serve as the mechanism by which weakly electric fish couple socially regulated and stress-regulated brain pathways to unique changes in the intrinsic excitability and action potential waveform of excitable membranes in peripheral cells involved in communication. Gymnotiform electric fish modulate their electric organ discharges (EODs) by reshaping the electric discharges of excitable cells in the periphery. These fish show circadian enhancement of the EOD waveform. They also enhance their EOD waveforms within minutes in response to stressors and changes in the social environment, thus altering the communication value of the signal. Changes in the EOD waveform that occur within minutes result from changes in the discharges of individual electrocytes (EODs) mediated by the cAMP/protein kinase A (PKA) pathway acting on ion channel kinetics. What activates the cAMP/PKA pathway in electrocytes has not been identified. In vivo injections of the melanocortin peptide adrenocorticotropic hormone (ACTH) increase the amplitude and duration of the electric signal waveform of the gymnotiform Brachyhypopomus pinnicaudatus over the course of 1 h. Applied to single electrocytes in vitro, ACTH increases EOD amplitude and duration within minutes by differentially modulating the action potentials of the two excitable membranes of the electrocyte and changing the timing of these two spikes. Serotonin modulates the EOD in vivo but has no effect on the EOD in vitro. The cAMP analog 8-bromo-cAMP mimicked the effects of ACTH, whereas inhibition of PKA by protein kinase A inhibitor 14 -22 amide blocked the modulatory effects of ACTH, confirming the role of the cAMP/PKA pathway in EOD modulation by ACTH.

show abstract

Section: Introductionsupporting

confidence: 86%

Adrenocorticotropic Hormone Enhances the Masculinity of an Electric Communication Signal by Modulating the Waveform and Timing of Action Potentials within Individual Cells

Markham

Stoddard²

2005

J. Neurosci.

View full text Add to dashboard Cite

show abstract

“…and stress 2 values were higher than prestress values, but significant differences were reached only in the healthy control group (Student's t test for paired observations, P =£ 0.025); asthmatic patients showed only a trend toward significance. Stress samples were drawn at the time when the diurnal cortisol curve is declining (35), thus diminishing the effect of our stressors. When this is taken into consideration, the increase from prestress to stress becomes more suggestive.…”

Section: Plasma Eortisolmentioning

confidence: 99%

Emotional and Adrenal Reactions to Stress in Bronchial Asthma

Mathé

Knapp

1971

Psychosomatic Medicine

View full text Add to dashboard Cite

Urinary epinephrine (E), norepinephrine (NE) and vanylmandelic acid (VMA), plasma cortisol and free fatty acids (FFA), respiratory and cardiovascular indices, and subjectively reported emotion were measured on successive days under conditions of stress and relaxation in 6 healthy males and 6 matched young males with perennial, mild-to-moderate bronchial asthma in remission. They had taken no medication for at least a week and no steroids for 6 months. Asthmatics, as compared to control Ss, had significantly lower urinary E values, during both stress and control periods. Initial levels of NE and VMA excretion in urine were normal; NE levels responded to stress as expected, but did not discriminate between groups. Plasma cortisol did not differ between groups in this small sample.These findings argue against a global sympathetic nervous system or adrenal cortical defect, and are consistent with the hypothesis of a specific hypothalamicadrenal medullary defect in bronchial asthma. Respiratory indices (unlike heart rate and blood pressure) differentiated between the groups: asthmatics had lower airway conductance and respiratory rate and an opposite direction of change in these indices under stress. Psychologically, asthmatic Ss exhibited a marked field independence and, although as emotionally aroused by stressors as were controls, gave evidence of inhibition of aggressive impulses.Study of endogenous catecholamines in bronchial asthma has been comparatively neglected, although epinephrine and isoproterenol are widely used and are eminently effective in asthmatic patients. Partial explanation may lie in the considerable From the

show abstract

“…Urinary epinephrine, norepinephrine and corticosteroid excretions are subject to diurnal variations of large amplitude (12,13). All are usually at a minimum during late evening and early morning hours and rise sharply during the last half of the habitual hours of sleep.…”

Section: Hormone Balance and Psychoendocrinologymentioning

confidence: 99%

“…The existence of a daily cycle of urine and plasma 17-OHCS levels has been known for several years, and the subject was reviewed recently by Nichols and Tyler (12). Plasma 17-OHCS levels are at their minimum during the first part of the habitual hours of sleep, reaching peak values around the habitual time of awakening.…”

Section: Periodicity Of Cortisol Secretionmentioning

confidence: 99%

See 1 more Smart Citation

Psychosomatics and Chronobiology: Possible Implications of Neuroendocrine Rhythms

Curtis

1972

Psychosomatic Medicine

View full text Add to dashboard Cite

Six of the variables involved in the psychoendocrine "catabolic-anabolic sequence" as defined by Mason-urinary corticosteroids, epinephrine, norepinephrine, aldosterone, urine volume and plasma growth hormoneundergo diurnal variations of large amplitude. Androgen secretion probably has, and estrogen, insulin and thyroid secretion may have, diurnal variations.The organization of the daily neuroendocrine cycle differs in important respects from that of the psychoendocrine catabolic-anabolic sequence. Alteration of normal phase relations among endocrine rhythms could have an impact on overall hormone balance equal to or greater than that of psychoendocrine responses as usually understood. Such alterations could occur either as a result of unusual living schedules or of impaired capacity of the organism to synchronize its rhythms with environmental cycles. The capacity to synchronize internal rhythms with each other and with environmental cycles appears to involve higher nervous activity and to depend on structural and functional integrity of the brain.Chronobiology is the study of biologic chronobiologic knowledge to the treatment of rhythms-ie, of the temporal structure of disease. organisms as opposed to the morphologic strucRecently the psychosomatic and chronobiture (1). Several subdivisions, including the fol-ology movements have begun to interact. It lowing, may be delineated: a) chronophysiolo-remains to be seen how fruitful the exchange gy, the study of normal rhythmic processes; b) will be, but a number of common interests are chronopharmacology, the study of rhythmic readily apparent. Both have strong commitfluctuations in the organism's response to drugs ments to the integrative approach in biologic and of drug effects on rhythmic functions; c) research; both are concerned with variations chronopathology, the study of the relationships within the physiologically normal range; both between rhythm abnormalities and disease; and have interests which extend from the molecular d) chronotherapeutics, the application of to the sociologic'levels of organization; and both aspire to improve the practice of clinical medicine. From the Eastern Pennsylvania Psychiatric Institute andA i m o f t e n s i o n i n t h e interaction is

show abstract

Diurnal Variation in Adrenal Cortical Function

Cited by 51 publications

References 0 publications

Adrenocorticotropic Hormone Enhances the Masculinity of an Electric Communication Signal by Modulating the Waveform and Timing of Action Potentials within Individual Cells

Adrenocorticotropic Hormone Enhances the Masculinity of an Electric Communication Signal by Modulating the Waveform and Timing of Action Potentials within Individual Cells

Emotional and Adrenal Reactions to Stress in Bronchial Asthma

Psychosomatics and Chronobiology: Possible Implications of Neuroendocrine Rhythms

Contact Info

Product

Resources

About