Hypothalamicα2- and β-adrenoceptor rhythms are correlated with circadian feeding: evidence from hronic methamphetamine treatment and withdrawal

Kräuchi, Kurt; Wirz‐Justice, Anna; Morimasa, Tadaomi; Willener, Rosi; Feer, H.

doi:10.1016/0006-8993(84)90683-8

Cited by 51 publications

(13 citation statements)

References 25 publications

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“…From the results described here, a lowered level of a2-receptor binding during the dark phase might be predicted; however, this appears not to have been the case in the study of Krauchi et al (1984) where peak binding occurred at dusk. Never¬ theless, it is apparent that there is a large degree of diversity, not only between different strains of rat (Di Lauro, Giannini, Muscettola et al 1986), but also between lines of rat strains (Jenni-Eiermann, von figure 5.…”

Section: Resultscontrasting

confidence: 71%

“…There is some evidence suggesting a circadian vari¬ ation in hypothalamic a2-adrenergic receptor binding (Krauchi, Wirz-Justice, Morimasa et al 1984), an effect probably due to a variation in receptor number rather than affinity. From the results described here, a lowered level of a2-receptor binding during the dark phase might be predicted; however, this appears not to have been the case in the study of Krauchi et al (1984) where peak binding occurred at dusk.…”

Section: Resultsmentioning

confidence: 99%

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Diurnal variation in the effect of potassium depolarization on vasoactive intestinal polypeptide release from rat hypothalamus: a possible role for adrenaline

Burns

Brown²,

Dobson³

1988

Journal of Endocrinology

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We have previously reported a lack of effect of a depolarizing concentration of K+ on the release of vasoactive intestinal polypeptide (VIP) from the perifused rat hypothalamus, and suggested that this was due to the presence of an endogenous inhibitor of the release of VIP. In this study we report that the VIP response to K+ was restored if the hypothalami were obtained from animals killed during the dark phase of the light-dark cycle. Adrenaline blocked the K+-stimulated release of VIP when used at a concentration of 0.1 mumol/l; however, at a higher concentration (10 mumol/l) adrenaline stimulated the basal release of VIP. The use of specific receptor antagonists indicated that this dual effect of adrenaline was mediated through two distinct receptors, a stimulatory beta-receptor and an inhibitory alpha 2-receptor. The suggestion that adrenaline might be the endogenous inhibitor of the release of VIP, mediating the diurnal variation in the effect of K+, was supported by studies where 50 mmol K+/l was perifused concomitantly with an alpha 2-antagonist, restoring the VIP response to K+ in light-phase hypothalami. In conclusion, adrenaline has a dual role in the control of VIP release and may function to inhibit the K+-stimulated release of VIP in our system.

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Section: Resultscontrasting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Diurnal variation in the effect of potassium depolarization on vasoactive intestinal polypeptide release from rat hypothalamus: a possible role for adrenaline

Burns

Brown²,

Dobson³

1988

Journal of Endocrinology

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“…We take this as evidence that the changes in binding are not due to diurnal variations in receptor oc cupancy, as has been reported with muscarinic binding sites in whole brain homogenates [II]. A redistribution of binding sites, perhaps from the surface of the cell mem brane to the interior of the cell, could be responsible for the observed change in BmaxDiurnal variations in neurotransmitter receptors in the central nervous system have been reported previously and have been correlated with similar changes in behavioral and physiological parameters [10,19]. The present report is the first to describe the correlation of a rhythm in neuro transmitter receptor binding with the ontogenetic appear ance of a physiological response.…”

Section: Discussionmentioning

confidence: 58%

Association of Diurnal Variations in Hypothalamic but Not Cortical Opiate ([<sup>3</sup>H]-Naloxone)-Binding Sites with the Ability of Naloxone to Induce LH Release in the Prepubertal Female Rat

Jacobson

Wilkinson

1986

Neuroendocrinology

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We report the existence of a diurnal variation in the binding of the opiate antagonist [³H]-naloxone to slices of the mediobasal hypothalamus from prepubertal female rats. The binding is highest in the early morning and reaches a nadir in the late afternoon. Opiate binding in cortical slices from such animals is constant over the course of the day. Changes in receptor density, and not in receptor affinity, account for the diurnal variation in the amount of ligand bound. These diurnal variations in receptor numbers are associated with changes in the ability of naloxone to release LH and may be crucial in the transition from the juvenile state to one of competent reproductive functioning.

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“…This, together with the observation of larger corpora lutea in the PCO anti-NGF group than in the PCO group, means that there is more cellular and active (according to our other data) tissue in the anti-NGF-treated PCO ovaries because the ovarian weights were equal in the two groups. The fluidfilled, dilated atretic follicles in the PCO group might be the reason for the lack of ovarian weight reduction found in previous studies (19).…”

Section: Discussionmentioning

confidence: 75%

Effect of anti-NGF on ovarian expression of α₁- and β₂-adrenoceptors, TrkA, p75^NTR, and tyrosine hydroxylase in rats with steroid-induced polycystic ovaries

Manni¹,

Holmäng²,

Cajander³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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(PCO) in rats are associated with higher ovarian release and content of norepinephrine, decreased ␤2-adrenoceptors (ARs), and dysregulated expression of ␣1-AR subtypes, all preceded by an increase in the production of ovarian NGF. The aim of this study was to further elucidate the role of NGF in the ovaries by blocking the action of NGF during development of EV-induced PCO in rats. Control and EV-injected rats were treated with intraperitoneal injections of IgG (control and PCO groups) or with anti-NGF antibodies (anti-NGF and PCO anti-NGF groups) every third day for 5 wk starting from the day of PCO induction. Rat weight, estrous cyclicity, ovarian morphology, ovarian mRNA, and protein expression of ␣1-AR subtypes, ␤2-AR, the NGF receptor tyrosine kinase A (TrkA), p75 neurotrophin receptor (p75 NTR ), and tyrosine hydroxylase (TH) were analyzed. Ovaries in both PCO and PCO anti-NGF groups decreased in size as well as in number and size of corpora lutea. mRNA expression of ␣ 1a-AR and TrkA in the ovaries was lower, whereas expression of ␣ 1b-and ␣1d-AR and TH was higher, in the PCO group than in controls. Protein quantities of ␣ 1-ARs, TrkA, p75 NTR , and TH were higher in the PCO group compared with controls, whereas the protein content of ␤ 2-AR was lower. Anti-NGF treatment in the PCO group restored all changes in mRNA and protein content, except that of ␣ 1b-AR and TrkA mRNAs, to control levels. The results indicate that the NGF/NGF receptor system plays a role in the pathogenesis of EV-induced PCO in rats.nerve growth factors; sympathetic nervous system; ovarian innervation; tyrosine kinase A; p75 neutrophin receptor POLYCYSTIC OVARY SYNDROME (PCOS) is a heterogeneous condition of uncertain etiology that affects between 5% and 10% of women of reproductive age (41). PCOS is characterized by a myriad of symptoms and signs, which include ovulatory dysfunction, the presence of polycystic ovaries (PCO), abdominal obesity, hyperandrogenism, and in many cases hypertension and insulin resistance (41). Several theories have been proposed to explain the pathogenesis of PCOS, such as an enhanced production of ovarian androgens, an alteration in the metabolism of cortisol resulting in enhanced production of adrenal androgens, a defect in the action and secretion of insulin, and a neuroendocrine defect that causes an exaggeration in the pulse and frequency amplitude of LH (41).The involvement of the sympathetic nervous system in the etiology and maintenance of PCOS is suggested by both clinical and experimental findings (5,20,22,24,25). Ovarian function is known to be regulated by both hormonal and intraovarian signaling. It is also known that the sympathetic innervation of the ovary is involved in follicular development (23) and in ovarian steroidogenesis (1). That the sympathetic nervous system is involved in the pathophysiology of human PCOS is supported by the fact that the innervation of the catecholaminergic nerve fibers in the PCO of women with PCOS is more dense than in normal ovaries (18,35).Chronic anovulati...

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Hypothalamicα2- and β-adrenoceptor rhythms are correlated with circadian feeding: evidence from hronic methamphetamine treatment and withdrawal

Cited by 51 publications

References 25 publications

Diurnal variation in the effect of potassium depolarization on vasoactive intestinal polypeptide release from rat hypothalamus: a possible role for adrenaline

Diurnal variation in the effect of potassium depolarization on vasoactive intestinal polypeptide release from rat hypothalamus: a possible role for adrenaline

Association of Diurnal Variations in Hypothalamic but Not Cortical Opiate ([<sup>3</sup>H]-Naloxone)-Binding Sites with the Ability of Naloxone to Induce LH Release in the Prepubertal Female Rat

Effect of anti-NGF on ovarian expression of α₁- and β₂-adrenoceptors, TrkA, p75^NTR, and tyrosine hydroxylase in rats with steroid-induced polycystic ovaries

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Hypothalamicα2- and β-adrenoceptor rhythms are correlated with circadian feeding: evidence from hronic methamphetamine treatment and withdrawal

Cited by 51 publications

References 25 publications

Diurnal variation in the effect of potassium depolarization on vasoactive intestinal polypeptide release from rat hypothalamus: a possible role for adrenaline

Diurnal variation in the effect of potassium depolarization on vasoactive intestinal polypeptide release from rat hypothalamus: a possible role for adrenaline

Association of Diurnal Variations in Hypothalamic but Not Cortical Opiate ([<sup>3</sup>H]-Naloxone)-Binding Sites with the Ability of Naloxone to Induce LH Release in the Prepubertal Female Rat

Effect of anti-NGF on ovarian expression of α1- and β2-adrenoceptors, TrkA, p75NTR, and tyrosine hydroxylase in rats with steroid-induced polycystic ovaries

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Effect of anti-NGF on ovarian expression of α₁- and β₂-adrenoceptors, TrkA, p75^NTR, and tyrosine hydroxylase in rats with steroid-induced polycystic ovaries