scholarly journals Endogenous Opioid Mechanisms Are Implicated in Obesity and Weight Loss in Humans

2015 ◽  
Vol 100 (8) ◽  
pp. 3193-3201 ◽  
Author(s):  
Paul R. Burghardt ◽  
Amy E. Rothberg ◽  
Kate E. Dykhuis ◽  
Charles F. Burant ◽  
Jon-Kar Zubieta
Keyword(s):  
Weight Loss ◽  
Endogenous Opioid ◽  
Opioid Mechanisms

Oestrous cycle-related LH responsiveness to naloxone: effect of high oestrogen levels on the activity of opioid receptors

1986 ◽  
Vol 108 (1) ◽  
pp. 89-94 ◽  
Author(s):  
F. Petraglia ◽  
V. Locatelli ◽  
F. Facchinetti ◽  
M. Bergamaschi ◽  
A. R. Genazzani ◽  
...  
Keyword(s):  
Time Of Day ◽  
Experimental Models ◽  
Significant Rise ◽  
Oestrous Cycle ◽  
Endogenous Opioid ◽  
Functional Changes ◽  
Opioid Mechanisms ◽  
Endogenous Opioid Systems ◽  
Lh Releasing Hormone ◽  
Lh Secretion

ABSTRACT Endogenous opioid peptides have a tonic inhibitory control on LH secretion, participating in the functional changes of the hypothalamic-pituitary-ovarian axis. To evaluate the activity of the endogenous opioid systems during the oestrous cycle, we measured plasma LH levels after naloxone administration (5 mg/kg, s.c.) at 09.00 and 16.00 h on all days of the cycle (two further measurements were taken at 14.00 and 18.00 h on the day of pro-oestrus) and after one dose or one week's treatment with oestradiol benzoate (OB; 0·2 μg/rat). Concentrations of LH were measured in the same experimental models after injection of LH-releasing hormone (LHRH; 1 μg/kg, i.p.) or saline. Naloxone induced a significant rise in LH levels on the day of oestrus, dioestrus day-1 and dioestrus day-2; this response was blunted on the morning of pro-oestrus and absent in the afternoon and after acute and chronic OB treatment. Conversely LHRH was most effective in increasing LH levels on the day of pro-oestrus and in OB-treated rats. These results indicate that opioid mechanisms, independently of the time of day and the pituitary responsiveness, exhibit a reduced activity when preovulatory changes occur, probably as a result of increased oestrogen levels. J. Endocr. (1986) 108, 89–94

scholarly journals Endogenous opioid mechanisms partially mediate P2X3 /P2X2/3 -related antinociception in rat models of inflammatory and chemogenic pain but not neuropathic pain

2005 ◽  
Vol 146 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Steve McGaraughty ◽  
Prisca Honore ◽  
Carol T Wismer ◽  
Joseph Mikusa ◽  
Chang Z Zhu ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Endogenous Opioid ◽  
Rat Models ◽  
Opioid Mechanisms

Fasting impairs LH secretion in female rats by activating an inhibitory opioid pathway

1985 ◽  
Vol 105 (1) ◽  
pp. 91-97 ◽  
Author(s):  
R. G. Dyer ◽  
S. Mansfield ◽  
H. Corbet ◽  
A. D. P. Dean
Keyword(s):  
Sampling Period ◽  
Significant Rise ◽  
Female Rats ◽  
Opioid Antagonist ◽  
Endogenous Opioid ◽  
Opioid Mechanisms ◽  
Before And After ◽  
Naloxone Hydrochloride ◽  
Lh Release ◽  
Lh Secretion

ABSTRACT Two experiments were undertaken to investigate the way that fasting impairs LH secretion and to assess whether endogenous opioid mechanisms might be responsible for the impairment. In the first experiment, pulsatile LH secretion was measured in a total of 51 chronically ovariectomized female rats. Initially 29 rats were subjected to food withdrawal for 24, 48, 72 or 120 h before the experiment. When compared with data collected from eight unfasted control rats, the 120-h fast was found to reduce significantly the mean peak and trough values of the LH pulses measured. However, in a subsequent study, the inhibition of pulsatile LH secretion by a 120-h fast was prevented in a group of eight rats given the opioid antagonist naloxone hydrochloride before the start of the blood-sampling period. Naloxone was without effect on pulsatile LH secretion in eight unfasted control rats. In the second experiment, plasma LH concentrations were measured before and after unilateral electrical stimulation of the ventral noradrenergic tract (VNAT) in ovariectomized female rats pretreated with oestradiol benzoate. In 17 rats VNAT stimulation caused a significant rise in plasma LH, but after a 72-h fast this rise was significantly less than in unfasted control rats. However, pretreatment of fasted rats with naloxone (n = 9) significantly enhanced the VNAT-stimulated release of LH to the control values. Naloxone did not potentiate VNAT-stimulated LH release in unfasted animals (n = 6) or LH release in control unstimulated rats (n = 12). The experiments indicate that both pulsatile LH secretion, and LH release caused by VNAT stimulation, are impaired by an acute fast. In both cases, the impairment is prevented by pretreatment with naloxone. Thus fasting probably activates an inhibitory opioid pathway within the brain to inhibit LH secretion. J. Endocr. (1985) 105, 91–97

Chronic clonidine treatment and endogenous opioid mechanisms

1988 ◽  
Vol 20 ◽  
pp. 127-128
Author(s):  
K. Varga ◽  
K. Simko ◽  
J. Kapocsi ◽  
C. Farsang
Keyword(s):  
Endogenous Opioid ◽  
Opioid Mechanisms

Recurrent Hypoxemia in Children Is Associated with Increased Analgesic Sensitivity to Opiates

2006 ◽  
Vol 105 (4) ◽  
pp. 665-669 ◽  
Author(s):  
Karen A. Brown ◽  
André Laferrière ◽  
Indrani Lakheeram ◽  
Immanuela Ravé Moss
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Desaturation ◽  
Respiratory Complications ◽  
Endogenous Opioid ◽  
Morphine Administration ◽  
Opioid Mechanisms ◽  
Obstructive Sleep ◽  
Increased Risk ◽  
History Of ◽  
Subsequent Administration

Background Postsurgical administration of opiates in patients with obstructive sleep apnea (OSA) has recently been linked to an increased risk for respiratory complications. The authors have attributed this association to an effect of recurrent oxygen desaturation accompanying OSA on endogenous opioid mechanisms that, in turn, alter responsiveness to subsequent administration of exogenous opiates. In a retrospective study, the authors have shown that oxygen desaturation and young age in children with OSA are correlated with a reduced opiate requirement for postoperative analgesia. Methods The current study was designed to test that conclusion prospectively in 22 children with OSA scheduled to undergo adenotonsillectomy. The children were stratified to those having displayed < 85% or > or = 85% oxygen saturation nadir during sleep preoperatively. Using a blinded design, the children were given morphine postoperatively to achieve an identical behavioral pain score. Results As compared with children in the > or = 85% group, the < 85% oxygen saturation nadir group required one half the total analgesic morphine dose postoperatively, indicating heightened analgesic sensitivity to morphine after recurrent hypoxemia. Conclusions Previous recurrent hypoxemia in OSA is associated with increased analgesic sensitivity to subsequent morphine administration. Therefore, opiate dosing in children with OSA must take into account a history of recurrent hypoxemia.

The psychobiology of hostility: Possible endogenous opioid mechanisms

1996 ◽  
Vol 3 (2) ◽  
pp. 163-176 ◽  
Author(s):  
Stephen Bruehl ◽  
James A. McCubbin ◽  
Charles R. Carlson ◽  
John F. Wilson ◽  
Jane A. Norton ◽  
...  
Keyword(s):  
Endogenous Opioid ◽  
Opioid Mechanisms
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