Opioid Peptides: Possible Physiological Role as Endogenous Anticonvulsants

1988 ◽  
pp. 163-179 ◽  
Author(s):  
Frank C. Tortella
Keyword(s):  
Opioid Peptides ◽  
Physiological Role

Characterization of the opioid receptor type mediating inhibition of rat gastric somatostatin secretion

1990 ◽  
Vol 259 (6) ◽  
pp. G922-G927
Author(s):  
C. H. McIntosh ◽  
X. Jia ◽  
Y. N. Kowk
Keyword(s):  
Opioid Receptor ◽  
Opioid Peptides ◽  
Physiological Role ◽  
Gastric Inhibitory Polypeptide ◽  
Opioid Peptide ◽  
Major Effect ◽  
Rat Stomach ◽  
Dependent Inhibition ◽  
High Concentrations ◽  
Mu Receptors

The opioid peptides are potent inhibitors of gastric somatostatin-like immunoreactivity (SLI) secretion from the isolated perfused rat stomach. In addition, inhibition of SLI secretion induced by vagal stimulation is partially blocked by naloxone, indicating that endogenously released opioid peptides probably play a physiological role in the regulation of SLI release. The opioid peptides exert their effects by interacting with a number of different receptor types. In the present study, the effect of the selective delta-opioid receptor agonists [D-Pen2.5]enkephalin and [D-Pen2,L-Pen5]enkephalin and the mu-receptor agonist [D-Ala2, N-methyl (NMe)-Phe4,Gly5-ol]enkephalin on gastric inhibitory polypeptide (GIP)-stimulated SLI secretion from the isolated perfused rat stomach have been studied. Responses to the less selective delta-agonist [D-Ala2,D-Leu5]enkephalin, dynorphins 1-8, 1-13, and 1-17, and the extended enkephalin forms Met-enkephalin-Arg6-Phe7,Met- enkephalin-Arg6-Gly7-Leu8, and Met-enkephalin-Arg6-Arg7-Val8-NH2 (metorphamide), have also been investigated. [D-Ala2,NMe-Phe4,Gly5-ol]enkephalin induced a concentration-dependent inhibition of GIP-stimulated SLI secretion, with 50% of maximal inhibition at 10 nM. Neither [D-Pen2.5]enkephalin nor [D-Pen2,L-Pen6]enkephalin (10 nM to 1 microM) had any effect on SLI release, and [D-Ala2,D-Leu5] enkephalin inhibited SLI release only at high concentrations. Met-enkephalin-Arg6-Phe7 and metorphamide both inhibited SLI release, whereas Met-enkephalin-Arg6-Gly7-Leu8 and the dynorphins had little or no effect. In conclusion, the strong inhibition of SLI secretion produced by [D-Ala2,NMe-Phe4,Gly5-ol] enkephalin and lack of major effect of [D-Pen2.5]-enkephalin, [D-Pen2,L-Pen5]enkephalin, and the dynorphins indicate that opioid peptide-induced inhibition was mediated by interaction with mu-receptors and that neither delta or kappa-receptors play a significant role.

Opioid peptides and testicular activity in the lizard Podarcis s. sicula Raf

1994 ◽  
Vol 143 (3) ◽  
pp. 565-571 ◽  
Author(s):  
G Ciarcia ◽  
F Facchinetti ◽  
M Vallarino ◽  
M Pestarino ◽  
M Paolucci ◽  
...  
Keyword(s):  
Opioid Peptides ◽  
High Performance ◽  
Physiological Role ◽  
Reproductive Activity ◽  
Opioid System ◽  
Endogenous Opioid System ◽  
Endogenous Opioid ◽  
Naltrexone Treatment

Abstract In mammals endorphinergic systems have been shown to modulate reproductive processes and β-endorphin (β-EP) has been found to influence sexual functions, acting at the hypothalamus-pituitary-gonadal axis level. Using immunocytochemical and in vitro studies, evidence for a diffuse pro-opiomelanocortin-related opioid system in the lizard Podarcis s. sicula was produced. In the testis, β-EP immunoreactivity showed seasonal variation, being most pronounced in the interstitial cells of sexually quiescent lizards (December). Reverse-phase high-performance liquid chromatography, coupled with radioimmunoassay and immunocytochemistry, showed that β-EP and acetyl β-EP increased during December, while their concentrations were low during April, when the highest testicular activity occurred. Using in vivo studies, it was found that naltrexone treatment, blocking pituitary opioid receptor, increased androgen levels in the plasma and in the testis. It was also found with in vitro studies that the endogenous opioid system inhibits gonadotrophin release and therefore androgen production by the testis. The data reported here provide evidence for the physiological role played by opioid peptides at the pituitary level to regulate the seasonal reproductive activity of the lizard Podarcis s. sicula. Journal of Endocrinology (1994) 143, 565–571

Role of cholecystokinin and opioid peptides in control of food intake

1986 ◽  
Vol 66 (1) ◽  
pp. 172-234 ◽  
Author(s):  
C. A. Baile ◽  
C. L. McLaughlin ◽  
M. A. Della-Fera
Keyword(s):  
Food Intake ◽  
Opioid Peptides ◽  
Direct Injection ◽  
Physiological Role ◽  
Control Food ◽  
The Many ◽  
Control Food Intake ◽  
The Brain ◽  
Opioid Receptor Types

Of the many factors that influence food intake, there is strong evidence that opioid and CCK peptides, which stimulate feeding and elicit satiety, respectively, are important components that may act in concert to regulate energy balance. Cholecystokinin peptides have been isolated in both the brain and gastrointestinal tract, and changes in concentration in the brain and in plasma have been shown to vary with feeding. Peripherally injected CCK has been shown to elicit satiety in many species, including humans, an effect that may be mediated in the CNS via the vagus. In several species, most notably the sheep, direct injection into the CSF potently decreases food intake. Questions remaining regarding the role of CCK peptides in eliciting satiety include the sites and mechanisms of action. It is unknown whether CCK acts directly on receptors, indirectly on some other parameter, or as a neurotransmitter. Although opioid peptides have also been localized in portions of both the periphery and brain, a specific physiological role for their presence has not yet been determined. Opioid peptides from three families--endorphins, enkephalins, and dynorphins--have been shown to stimulate feeding in various species. They have been active at several opioid receptor types in the CNS, but there is limited evidence to suggest they affect food intake when administered peripherally. In contrast, peripheral injection of opiate antagonists has effectively decreased food intake, an observation that led to the original hypothesis that opioids were involved in the hunger component in the control of food intake and that excess concentrations might be involved in the development of obesity. An increasing body of evidence supports the concept that opioid and CCK peptides may interact to control food intake, but the evidence is more suggestive than conclusive.

Alleviation of pain and depression by specific neural transplants: Fine structural correlates

1992 ◽  
Vol 50 (2) ◽  
pp. 1066-1067
Author(s):  
George D. Pappas ◽  
Jacqueline Sagen
Keyword(s):  
Opioid Peptides ◽  
Chromaffin Cells ◽  
Pain Sensitivity ◽  
Opioid Peptide ◽  
Local Source ◽  
Pain Models ◽  
Neural Transplants ◽  
Adrenergic Antagonists ◽  
Csf Levels ◽  
Donor Source

We have been interested in the use of neural transplants mainly as a local source of neuroactive substances, rather than as a replacement for damaged neural circuities. In particular, we have been exploring the possibilities of reducing pain by transplants of opioid peptide producing cells, and reducing depression by transplants of monoamine-producing cells. For the past several years, work in our laboratory has demonstrated in both acute and chronic pain models that transplantation of adrenal medullary tissue or isolated chromaffin cells into CNS pain modulatory regions can reduce pain sensitivity in rodents. Chromaffin cells were chosen as donor source since they produce high levels of both opioid peptides and catecholamines, substances which independently, and probably synergistically, reduce pain sensitivity when injected locally into the spinal cord. The analgesia produced by these transplants most likely results from the release of both opioid peptides and catecholamines, since it can be blocked or attenuated by opiate or adrenergic antagonists, respectively. Furthermore, CSF levels of met-enkephalin and catecholamines are increased by the transplants.

Detection and mapping of interactions between chromatin and the nuclear envelope in drosophila embryos

1995 ◽  
Vol 53 ◽  
pp. 764-765
Author(s):  
W.F. Marshall ◽  
A.F. Dernburg ◽  
B. Harmon ◽  
J.W. Sedat
Keyword(s):  
Nuclear Envelope ◽  
Chromatin Condensation ◽  
Three Dimensional ◽  
Physiological Role ◽  
Nuclear Surface ◽  
Intact Cells ◽  
Molecular Determinants ◽  
Surface Harmonic ◽  
Drosophila Embryos

Interactions between chromatin and nuclear envelope (NE) have been implicated in chromatin condensation, gene regulation, nuclear reassembly, and organization of chromosomes within the nucleus. To further investigate the physiological role played by such interactions, it will be necessary to determine which loci specifically interact with the nuclear envelope. This will not only facilitate identification of the molecular determinants of this interaction, but will also allow manipulation of the pattern of chromatin-NE interactions to probe possible functions. We have developed a microscopic approach to detect and map chromatin-NE interactions inside intact cells.Fluorescence in situ hybridization (FISH) is used to localize specific chromosomal regions within the nucleus of Drosophila embryos and anti-lamin immunofluorescence is used to detect the nuclear envelope. Widefield deconvolution microscopy is then used to obtain a three-dimensional image of the sample (Fig. 1). The nuclear surface is represented by a surface-harmonic expansion (Fig 2). A statistical test for association of the FISH spot with the surface is then performed.

Modified Solid-Phase Methods for the Rapid Synthesis of Opioid Peptides

1991 ◽  
Author(s):  
Richard A. Houghten ◽  
◽  
John M. Ostresh ◽  
Suzanne M. Pratt
Keyword(s):  
Opioid Peptides ◽  
Solid Phase ◽  
Rapid Synthesis

Effect of prolactin inhibition under heat exposure on water intake and excretion of urine, sodium and potassium in bulls

1980 ◽  
Vol 94 (3) ◽  
pp. 315-320 ◽  
Author(s):  
D. Schams ◽  
E. Stephan ◽  
R. D. Hooley
Keyword(s):  
Water Intake ◽  
Heat Exposure ◽  
Physiological Role ◽  
Treated Group ◽  
Serum Prolactin ◽  
Control Value ◽  
Light Regimen ◽  
Group I ◽  
Urinary Potassium ◽  
Group Ii

Abstract. Six Holstein bulls were housed in a climate-chamber under constant light regimen and after two weeks of preconditioning at 15°C, 60% relative humidity RH (day) and 12°C, 60% RH (night) were subjected to two weeks of heat exposure. This involved one week at 30°C and 60% RH (day) and 25°C and 60% RH (night) and a further week at 35°C, 60% RH (day) and 30°C, 60% RH (night). Three bulls were untreated (group I) and 3 bulls were treated (group II) just before and during heat exposure with a prolactin inhibitor to study the possible physiological role of prolactin on the regulation of water, potassium and sodium. Serum prolactin levels increased significantly (P < 0.01) in group I from the control value of 6 ng/ml to 33 and 44 ng/ml when the ambient temperature was increased (weeks 3 and 4) and then decreased to 21 and 12 ng/ml after reduction in temperature during weeks 5 and 6, respectively. For group II prolactin values decreased under the treatment with the prolactin inhibitor to 0.5 ng/ml and remained at this level throughout the experiment. GH levels were unaffected by heat treatment or by treatment with prolactin inhibitor. There were no differences between groups I and II in respiratory rate, pulse rate and rectal temperature. Water intake increased in both groups under heat exposure but decreased significantly afterwards only in group II. Differences in urinary excretion volume and blood serum osmolality were not significant. Urinary potassium and sodium excretion were unchanged in group II but increased with heat exposure in group I. During heat exposure 2 bulls of group II lost weight despite maintaining food intake.

Physiological role for Angptl4/fiaf in exercise-induced muscle AMPK activation

2013 ◽  
Author(s):  
Min-Seon Kim ◽  
Ghi-Su Kim ◽  
Hyuckki Chang ◽  
Mi-Seon Shin ◽  
Hyun Kyong Kim
Keyword(s):  
Physiological Role ◽  
Ampk Activation ◽  
Exercise Induced
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