The opioid κ-selective compound U−50,488H does not inhibit intestinal propulsion in rats

Tavani, Alessandra; Gambino, Maria Concetta; Petrillo, Paola

doi:10.1111/j.2042-7158.1984.tb04391.x

Cited by 27 publications

(13 citation statements)

References 7 publications

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“…In addition to antinociception, a slowed gut transit is characteristic of late pregnancy [4]. Of particular importance, here, are the findings that pregnancy antinociception is mediated by n-opioid [26] and y-opioid [5] receptors, that the opioid-based slowing of gut transit is mediated by A-opioid receptors [2,12,23,24,28], and that ingested placenta enhances n-and yreceptor-mediated antinociception but inhibits A-receptormediated antinociception [7]. Therefore, as suggested by the present results, ingestion of placenta or amniotic fluid at parturition may enhance the antinociception of pregnancy as well as help restore normal gut transit after parturition, particularly when transit has been slowed by activity at Aopioid receptors in the CNS.…”

Section: Discussionmentioning

confidence: 99%

“…Another effect of central or systemic opioids is a slowing of gut transit [3,6,15], which is believed to be mediated by A-opioid receptor activity both centrally and peripherally [2,12,23,24,28]. This is believed to occur centrally by action in the dorsal vagal complex of the hindbrain [10], which is part of the vagovagal neurocircuitry that influences gastrointestinal function [11], yet it is believed to occur peripherally by disruption of the role of local opioids in intestinal muscular contraction and relaxation [22,23].…”

Section: Introductionmentioning

confidence: 99%

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Ingested placenta blocks the effect of morphine on gut transit in Long–Evans rats

Corpening¹,

Doerr²,

Kristal³

2004

Brain Research

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Opioids produce antinociception, and ingested placenta or amniotic fluid modifies that antinociception. More specifically, ingested placenta enhances the antinociception produced by selective activation of central n-opioid or y-opioid receptors but attenuates that produced by activation of central A-opioid receptors. Opioids also slow gut transit by acting on central or peripheral A-opioid receptors. Therefore, we hypothesized that ingested placenta would reverse the slowing of gut transit that is produced by morphine, a preferential A-opioid-receptor agonist. Rats were injected with morphine either centrally or systemically and fed placenta, after which gastrointestinal transit was evaluated. We report here that ingested placenta reversed the slowing of gut transit produced by centrally administered morphine but did not affect the slowing of gut transit produced by systemically administered morphine. These results suggest another likely consequence of placentophagia at parturition in mammals-reversal of opioid-mediated, pregnancy-based disruption of gastrointestinal function-as well as an important consideration in opioid-based treatments for pain in humans-enhancement of desirable effects with attenuation of adverse effects. D 2004 Elsevier B.V. All rights reserved.Theme: Endocrine and autonomic regulation Topic: Gastrointestinal and urogenital regulation

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ingested placenta blocks the effect of morphine on gut transit in Long–Evans rats

Corpening¹,

Doerr²,

Kristal³

2004

Brain Research

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“…All three types are present in the intestinal wall of the rat Dashwood et al, 1985;Fickel et al, 1997;Gray et al, 2005;Nishimura et al, 1986;Sternini et al, 1995). A and y receptor activation each lead to gastrointestinal transit arrest in the rat (La Regina et al, 1988;Tavani et al, 1984Tavani et al, , 1990, and our group has recently shown that these receptors mediate inhibition of electrically induced neurogenic smooth muscle contractions in the rat ileum (Gray et al, 2005). A receptors also appear to mediate anti-secretory effects (Coupar, 1983).…”

Section: Introductionmentioning

confidence: 90%

Comparison of opioid receptor distributions in the rat ileum

2006

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“…The -opioid receptor distributions in the brain and gastrointestinal tract of humans and guinea pigs are similar, with respect to both overall receptor distribution and the prevalence of the high-affinity receptor subtype. For some aspects of the opioid system, the guinea pig may therefore prove to be a better animal model than the rat, which has a lower overall abundance of -opioid receptors that are primarily of the low-affinity subtype (18,63,78).We report here on the isolation and sequencing of the guinea pig preproenkephalin gene and its expression in the brain. Unexpectedly, we have also identified a site-specific cleavage in the 3Ј untranslated region (3Ј UTR) of preproenkephalin mRNA which yields 3Ј-truncated transcripts in specific brain regions, including the caudate putamen, nucleus accumbens, and amygdala.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Structure and Expression of the Guinea Pig Preproenkephalin Gene: Site-Specific Cleavage in the 3′ Untranslated Region Yields Truncated mRNA Transcripts in Specific Brain Regions

LaForge

Unterwald

Kreek

1995

Molecular and Cellular Biology

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We isolated the guinea pig preproenkephalin gene from a genomic library by hybridization to a rat cDNA probe. The entire nucleotide sequence of the gene was determined. Genomic Southern blot hybridization demonstrated that the gene exists in a single copy within the genome. On the basis of RNase protection transcript mapping and homology comparisons with known preproenkephalin sequences from other species and assuming a poly(A) tail length of 100 residues, we predicted an mRNA transcript of approximately 1,400 nucleotides encoded by three exons. Northern (RNA) blot analysis of total RNA from several brain regions showed high levels of preproenkephalin mRNA in the caudate putamen, nucleus accumbens, and hypothalamus, with detectable levels in the amygdala, ventral tegmental area, and central gray and also in the pituitary. Unexpectedly, in several brain regions, the mRNA appeared not only in the 1,400-nucleotide length but also in a shorter length of approximately 1,130 bases. Significant amounts of the shorter mRNA were found in the caudate putamen, nucleus accumbens, and amygdala. The longer, but not the shorter, transcripts from the caudate putamen were found to be polyadenylated, but the difference in size was not due solely to the presence of poly(A) tails. Northern gel analysis of total RNA from the caudate putamen with probes from each exon, together with RNase protection mapping of the 3 end of the mRNA demonstrated that the 1,400-base preproenkephalin mRNA transcripts are cleaved in a site-specific manner in some brain regions, yielding a 1,130-base transcript and a 165-base polyadenylated fragment derived from the terminal end of the 3 untranslated region of the mRNA. This cleavage may serve as a preliminary step in RNA degradation and provide a mechanism for control of preproenkephalin mRNA abundance through selective degradation.The preproenkephalin gene is one of three genes, along with the preprodynorphin and preproopiomelanocortin genes, that encode precursor proteins from which are derived all endogenous opioid peptides. These peptides contain the methionineenkephalin ([Met 5 ]enkephalin) or leucine-enkephalin ([Leu 5 ] enkephalin) sequence motif and exhibit a diversity of functions as neurotransmitters, neuromodulators, and hormones. Preproenkephalin is widely expressed in the brain and peripheral nervous system as well as in the pituitary, male and female reproductive tracts, adrenal medulla, gastrointestinal tract, lymphocytes, and other tissues. The preproenkephalin gene sequences from humans, rats, and golden hamsters have been previously reported (46,52,77), as have the cDNA sequences from humans, rats, mice, cattle, and Xenopus laevis (17,26,37,40,45,76,79). Characteristic features of preproenkephalin from mammalian species in which the gene or mRNA structure has been determined include a signal sequence, six cysteine residues in the amino-terminal region of the propeptide, and seven enkephalin-containing peptide sequences flanked by basic amino acid residues. Proteolytic processing of...

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The opioid κ-selective compound U−50,488H does not inhibit intestinal propulsion in rats

Cited by 27 publications

References 7 publications

Ingested placenta blocks the effect of morphine on gut transit in Long–Evans rats

Ingested placenta blocks the effect of morphine on gut transit in Long–Evans rats

Comparison of opioid receptor distributions in the rat ileum

Structure and Expression of the Guinea Pig Preproenkephalin Gene: Site-Specific Cleavage in the 3′ Untranslated Region Yields Truncated mRNA Transcripts in Specific Brain Regions

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