Interruption of parturition in rats by morphine: a result of inhibition of oxytocin secretion

1989 ◽  
Vol 121 (3) ◽  
pp. 521-536 ◽  
Author(s):  
J. A. Russell ◽  
R. G. Gosden ◽  
E. M. Humphreys ◽  
R. Cutting ◽  
N. Fitzsimons ◽  
...  
Keyword(s):  
Contractile Activity ◽  
Post Partum ◽  
Maternal Behaviour ◽  
Opiate Antagonist ◽  
Opioid Receptor Agonist ◽  
Μ Opioid Receptor ◽  
Pup Mortality ◽  
Mean Time

ABSTRACT Oxytocin secretion is inhibited by opioids, and oxytocin is important in parturition. The effects on parturition of morphine, a relatively selective μ-opioid receptor agonist, were studied in the rat. Morphine or vehicle with or without the opiate antagonist naloxone were administered immediately after the birth of the second pup and the subsequent course of parturition was recorded in a total of 80 rats. Both s.c. morphine (10 mg/kg) and intracerebroventricular (i.c.v.) morphine (18 μg through a previously implanted cannula) interrupted parturition, delaying the birth of the sixth pup after treatment to 187·3 ± 35·9 (s.e.m.) min and 195·4 ± 19·5 min respectively, compared with 46·4 ± 3·7 and 66·1 ± 17·5 min after vehicle alone. The dose of morphine given i.c.v. had no effect when given s.c. Naloxone given concurrently prevented the effects of morphine. Eventually the rate of parturition in the morphine-treated groups recovered. Perinatal pup mortality rate was not increased when morphine was given to the mothers, but it did inhibit the expression of normal intrapartum maternal behaviour. Pup mortality was increased 48 h post partum by morphine given during parturition, and it reduced the proportion of rats with normal maternal behaviour 24 h post partum. Morphine did not affect spontaneous or oxytocin-stimulated contractile activity of the parturient uterus in vitro. The concentration of oxytocin in trunk blood plasma was decreased 40 min after i.c.v. morphine (24·3 ± 3·9 vs 39·3± 6·5 pmol/l in controls), as was vasopressin (7·2 ± 1·5 vs 19·7 ± 4·5 pmol/l in controls). Intravenous infusion of oxytocin (2–5 mU/min for 144·3 ± 8·2 min; total infused 448·5 ± 61·9 mU) after i.c.v. morphine re-started parturition; all pups were born to these rats (mean time to pup 6, 110·3 ± 12·7 min) before the i.v. vehicle-infused rats given i.c.v. morphine re-started (mean time to pup 6, 406·3±125·2 min). It is concluded that morphine given during parturition acts centrally through opioid receptors to inhibit oxytocin secretion, and impairs the expression of maternal behaviour. Reversal of the effects of morphine on parturition by i.v. oxytocin demonstrates the important role of oxytocin in fetus ejection and expulsion. Journal of Endocrinology (1989) 121, 521–536

Optoelectronic transducer for in vivo recording of oviductal contractile activity

1980 ◽  
Vol 239 (3) ◽  
pp. R326-R331
Author(s):  
S. A. Halbert ◽  
R. J. Bourdage ◽  
J. L. Boling ◽  
J. A. Ringo ◽  
R. J. Blandau
Keyword(s):  
Contractile Activity ◽  
Red Light ◽  
Muscular Activity ◽  
Optical Signal ◽  
In Vivo Experiments ◽  
Optoelectronic Transducer ◽  
Optical Analog

An optoelectronic instrument to record oviductal muscular activity in chronically instrumented animals was evaluated in in vitro and in vivo experiments. The intensity of red light transmitted through the oviduct was modulated by contractions of the oviductal wall producing an optical analog of the mechanical events. Accuracy of the analog was tested by Fourier analysis of signals from mechanical and optoelectronic transducers placed at the same site on the oviduct; the results validated the use of the optical device as a contraction event sensor. Contractions of the tubal mesenteries had less effect on the optical signal than on signals from extraluminal mechanical transducers. Optical and photographic recordings of luminal transport in exposed oviducts showed a correspondence of intraluminal movements to events in the optical contraction signal. This instrument does not alter tubal function, and thus it is an especially useful experimental tool to investigate the role of oviductal muscular activity in fertility.

Role of CDK5 in neuroprotection from serum deprivation by μ-opioid receptor agonist

2006 ◽  
Vol 202 (2) ◽  
pp. 313-323 ◽  
Author(s):  
Y WANG ◽  
W XIE ◽  
Y HE ◽  
M WANG ◽  
Y YANG ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Receptor Agonist ◽  
Serum Deprivation ◽  
Opioid Receptor Agonist ◽  
Μ Opioid Receptor

In vivo and in vitro evaluation of novel μ-opioid receptor agonist compounds

2015 ◽  
Vol 767 ◽  
pp. 193-200 ◽  
Author(s):  
Yoshiaki Nikaido ◽  
Aya Kurosawa ◽  
Hitomi Saikawa ◽  
Satoshi Kuroiwa ◽  
Chiharu Suzuki ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Receptor Agonist ◽  
In Vitro Evaluation ◽  
Opioid Receptor Agonist ◽  
Μ Opioid Receptor

RELATIONSHIP BETWEEN INSULIN CONCENTRATIONS IN PLASMA AND PANCREAS OF FOETAL AND WEANLING RATS

1970 ◽  
Vol 48 (4) ◽  
pp. 553-561 ◽  
Author(s):  
E. BLÁZQUEZ ◽  
E. MONTOYA ◽  
CLEMENTE LÓPEZ QUIJADA
Keyword(s):  
Plasma Insulin ◽  
Striated Muscle ◽  
Slow Growth ◽  
Post Partum ◽  
Newborn Rat ◽  
Plasma Insulin Concentration ◽  
Pregnant Rats ◽  
Weanling Rats

SUMMARY During the third part of pregnancy in the rat the concentrations of plasma insulin and tissue glycogen in the foetus increase progressively. These levels and the release of insulin by pancreas incubated in vitro were significantly higher than the values found in adult non-pregnant rats. After birth the correlation between plasma insulin concentration and the stores of glycogen was also evident. In the first day of life, the concentrations of plasma insulin, glycogen in liver, striated muscle and kidney decreased significantly; these values decrease even more during the first 15 days of lactation. After weaning started (20 days post partum), rapid increases of insulin and glycogen were observed, parallel to the slow growth of the newborn rat during the first 15 days of life and the more rapid rate of growth after 20 days. Similarly, the insulin content of the pancreas increased more significantly during the period in which pancreatic weight and plasma insulin concentrations increased more slowly. These results show that when plasma insulin concentrations increase, body growth and stores of glycogen are higher, suggesting an anabolic role of insulin in the foetal and newborn rat.

Pethidine (meperidine) inhibition of oxytocin secretion and action in parturient rats

1991 ◽  
Vol 261 (2) ◽  
pp. R358-R368
Author(s):  
J. A. Russell ◽  
G. Leng ◽  
J. E. Coombes ◽  
S. A. Crockett ◽  
A. J. Douglas ◽  
...  
Keyword(s):  
Opioid Receptors ◽  
Post Partum ◽  
Opiate Antagonist ◽  
Milk Ejection ◽  
Milk Ejection Reflex

Pethidine (also known as meperidine and as Demerol) injected subcutaneously at 10 mg/kg into parturient rats on the birth of the second pup resulted in a marked slowing of the progress of parturition, associated with reduced plasma oxytocin concentrations. Injection of the opiate antagonist naloxone counteracted the inhibition of oxytocin secretion and largely prevented the slowing of parturition. In vitro, pethidine inhibited spontaneous, oxytocin-induced and acetylcholine-induced contractions of uteri from rats immediately post partum, and these effects were not reversed by naloxone. In anesthetized lactating rats, pethidine inhibited the suckling-induced milk-ejection reflex and attenuated oxytocin-induced contractions of mammary myoepithelium. Finally, pethidine depressed plasma oxytocin concentrations in rats given 2% saline to drink for 24 h to stimulate oxytocin secretion. Thus pethidine inhibits oxytocin secretion in all three conditions; this inhibition is probably mediated by central opioid receptors. In addition, however, pethidine depresses the oxytocin responsiveness both of mammary myoepithelium and of myometrium. The latter effect at least is not opioid mediated.

Role of kinin B2 receptors in opioid-induced hyperalgesia in inflammatory pain in mice

2013 ◽  
Vol 394 (3) ◽  
pp. 361-368 ◽  
Author(s):  
Sébastien Grastilleur ◽  
Lionel Mouledous ◽  
Jerome Bedel ◽  
Jonathan Etcheverry ◽  
Michael Bader ◽  
...  
Keyword(s):  
Inflammatory Pain ◽  
Postoperative Pain Management ◽  
Kinin Receptors ◽  
Opioid Receptor Agonist ◽  
Opioid Induced Hyperalgesia ◽  
Μ Opioid Receptor ◽  
Baseline Values ◽  
B2 Receptors ◽  
Von Frey Filaments

Abstract Postoperative pain management is a clinical challenge that can be complicated by opioid-induced hyperalgesia (OIH). Kinin receptors could mediate both the acute and chronic phases of inflammation and pain. A few recent studies suggest that dynorphin A could maintain neuropathic pain by activating the bradykinin (BK) receptor. Thus, the effect of a single administration of sufentanil (a μ-opioid receptor agonist) was investigated in a model of carrageenan-induced inflammatory pain using three strains of mice, i.e., knockout mice for one kinin receptor, B1R or B2R (B1KO, B2KO), and wild-type C57/BL6J mice (WT) treated with either a B1R (R954) or a B2R antagonist (HOE140) or a KKS inhibitor (aprotinin). Pain was assessed and compared between the different groups using two behavioral tests exploring mechanical (von Frey filaments) and thermal (Hargreaves test) sensitivity. Pretreatment with sufentanil induced a sustained increase in pain sensitivity with a delayed return to baseline values characterizing an OIH in carrageenan-injected mice only. Sufentanil-induced OIH was not observed in B2KO but persisted in B1KO and was blunted by aprotinin and the B2R antagonist only. Collectively, our data indicate that the B2R receptor and BK synthesis or availability are essential peripheral steps in the mechanism leading to OIH in a pain context.

Possible role of the erythrocyte in causing prolonged cerebral vasospasm

1979 ◽  
Vol 51 (6) ◽  
pp. 773-778 ◽  
Author(s):  
Nobuyuki Ozaki ◽  
Sean Mullan
Keyword(s):  
Cerebral Vasospasm ◽  
Contractile Activity ◽  
Platelet Rich Plasma ◽  
Red Cells ◽  
Significant Activity ◽  
Sephadex Column ◽  
Content Type ◽  
Canine Basilar Artery

✓ Contractile activity of the various fractions of fresh and incubated blood was studied in vitro using the isolated canine basilar artery. Of the various fractions of fresh blood, significant contraction was induced by serum, but moderate contraction was induced by platelet-rich plasma and lysed red cells, while intact red cells and platelet-poor plasma had no significant activity. The contractions induced by serum and platelet-rich plasma were blocked by phenoxybenzamine, while those induced by lysed red cells were not. Whereas serum and platelet-rich plasma lost their contractile activity after 24 hours of incubation, lysed red cells retained activity up to 7 days after incubation. Biochemical analysis of the hemolysate by means of Sephadex column chromatography revealed that the contractile substance(s) possessed a molecular weight above 5000. These results suggest the possibility that the above substance(s) may play a role in prolonged cerebral vasospasm.

scholarly journals Dietary mannose supplementation in phosphomannomutase 2 deficiency (PMM2-CDG)

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Roman Taday ◽  
Marianne Grüneberg ◽  
Ingrid DuChesne ◽  
Janine Reunert ◽  
Thorsten Marquardt
Keyword(s):  
Biological Effects ◽  
Randomized Study ◽  
Protein Glycosylation ◽  
Therapeutic Approaches ◽  
Double Blind ◽  
Time Period ◽  
Mean Time

Abstract Background PMM2-CDG (CDG-Ia) is the most frequent N-glycosylation disorder. While supplying mannose to PMM2-deficient fibroblasts corrects the altered N-glycosylation in vitro, short term therapeutic approaches with mannose supplementation in PMM2-CDG patients have been unsuccessful. Mannose found no further mention in the design of a potential therapy for PMM2-CDG in the past years, as it applies to be ineffective. This retrospective study analyzes the first long term mannose supplementation in 20 PMM2-CDG patients. Mannose was given at a total of 1–2 g mannose/kg b.w./d divided into 5 single doses over a mean time of 57,75 ± 25,85 months. Protein glycosylation, blood mannose concentration and clinical presentation were monitored in everyday clinical practice. Results After a mean time period of more than 1 year the majority of patients showed significant improvements in protein glycosylation. Conclusion Dietary mannose supplementation shows biological effects in PMM2-CDG patients improving glycosylation in the majority of patients. A double-blind randomized study is needed to examine the role of mannose in the design of a therapy for children with PMM2-CDG in more detail.

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