Opioid Peptides of The Gut

Miller, Richard J.; Hirning, Lane D.

doi:10.1002/cphy.cp060226

Cited by 17 publications

(10 citation statements)

References 276 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Opioids affect the intestines by one of three mechanisms: reduction in motility (propulsive peristalsis) and secretions (pancreatic, biliary, electrolytes and fluid) and increases in intestinal fluid absorption and blood flow [10][11][12][13].…”

Section: Opioid Effects On the Gastrointestinal Tractmentioning

confidence: 99%

Constipation in advanced cancer patients

Mancini

Bruera

1998

Support Care Cancer

147

View full text Add to dashboard Cite

Constipation is a frequent, distressing, and underestimated complication in patients with advanced cancer. It may develop from general disturbances that may or may not be cancer related, but the use of opioids is one of the main causes in this population. Opioids affect the intestine by reducing motility and secretions and by increasing fluid absorption and blood flow. Untreated constipation may lead to several complications. Effective management of constipation starts with a careful assessment of the patient, including the history of the frequency and difficulty of defaecation, symptoms caused by constipation, and physical and rectal examinations. When the diagnosis of constipation is unclear, an abdominal X-ray may be required. The treatment of constipation includes general interventions, such as the availability of comfort and privacy or the elimination of medical factors that may contribute to constipation, and therapeutic interventions including oral or rectal laxatives and the use of prokinetic drugs and naloxone. The purpose of this paper is to review the pathophysiology and causes of constipation and the effects of opioids on the gastrointestinal tract, and to propose an approach for its assessment and management. Randomized clinical trials between different laxatives and/or prokinetic agents in cancer patients are needed, and future studies should focus on the validation of different clinical assessment tools for constipation.

show abstract

Section: Opioid Effects On the Gastrointestinal Tractmentioning

confidence: 99%

Constipation in advanced cancer patients

Mancini

Bruera

1998

Support Care Cancer

147

View full text Add to dashboard Cite

show abstract

“…Immunohistochemical studies have revealed that the opioid receptor subtypes, μ , δ and κ , are present in neural tissue of the rat enteric nervous system (ENS), but not in smooth muscle cells (Sternini et al ., 1995; Bagnol et al ., 1997; Gray et al ., unpublished observations). Although transit arrest is a common effect of opioids in mammals, underlying secretomotor changes appear to vary between species (Miller & Hirning, 1989). In the rat, the issue has been complicated by reports of differing tissue responses under different experimental conditions (Burks, 1976; Coupar & De Luca, 1994); studies have examined drug effects on unstimulated tissues, as well as tissues stimulated exogenously with electrical pulses.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of opioid receptors involved in modulating circular and longitudinal muscle contraction in the rat ileum

Gray

White

Coupar

2005

British J Pharmacology

View full text Add to dashboard Cite

1 The aim of the present investigation was to characterise the opioid receptor subtypes present in the rat ileum using a method that detects drug action on the enteric nerves innervating the circular and longitudinal muscles. ). Agonist potencies were generally within expected ranges for activity at the subtype for which they are selective, except for U 50488H, which was less potent than expected. 3 The m and d receptor-selective antagonists, CTAP (H-D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH 2 ) and naltrindole, caused progressive, parallel rightward shifts in the DAMGO and DADLE curves, respectively. Analysis indicated conformity to theoretical simple competitive antagonist behaviour. U 50488H effects were insensitive to the k-selective antagonist, n-BNI. A high concentration (1 mM) of naltrexone caused apparent potentiation of U 50488H effects. 4 CTAP pK B estimates were consistent with previously reported values for m receptor antagonism (circular 7.8470.17, longitudinal 7.6470.35). However, the naltrindole pK B estimates indicated lower antagonist potency than expected (circular 8.2270.23, longitudinal 8.5370.35). 5 It is concluded that m and possibly atypical d receptors (but not k receptors) mediate inhibition of contraction in this model. Nonopioid actions of U 50488H are probably responsible for the inhibitory effects seen with this compound.

show abstract

“…' Author for correspondence. Exogenous opioids alter intestinal motility both in vivo and in vitro (Kromer, 1988;Miller & Hirning, 1989). Furthermore, endogenous opioids exist in the enteric nervous system of many mammalian species (Hughes et al, 1977;Linnoila et al, 1978;Furness et al, 1983;Costa et al, 1985;Corbett et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Modulation of peristalsis in the guinea‐pig isolated small intestine by exogenous and endogenous opioids

Waterman

Costa

Tonini

1992

British J Pharmacology

View full text Add to dashboard Cite

1 A recording method was developed to measure physiological parameters of the preparatory and emptying phases of peristalsis in vitro. This method enabled measurement of: the compliance of the intestinal wall during the preparatory phase (a reflection of the resistance of the wall to distension); longitudinal muscle contraction during the preparatory phase; the threshold volume required to trigger the emptying phase; the maximal ejection pressure and the average power generated during the emptying phase, which reflects the rate at which the intestine performs work. Modulation of these parameters by exogenous and endogenous opioids acting at p, K and 6 opioid receptors was investigated.2 The compliance of the intestinal wall during the preparatory phase was reduced by the ft opioid receptor agonist, [D-Ala2, N-methyl-Phe4, Gly5-ol] enkephalin (DAMGO) but not by the K agonist, dynorphin, or the 6 agonist, [D-penicillamine2, D-penicillamine5] enkephalin (DPDPE). Reflex contraction of the longitudinal muscle during the preparatory phase was inhibited by DAMGO, dynorphin and DPDPE. The threshold volume required to trigger the emptying phase of peristalsis was increased by DAMGO, dynorphin and DPDPE. 3 The maximal ejection pressure generated during the emptying phase was reduced by dynorphin and DPDPE, but not by DAMGO. The average power generated by the intestine when emptying was not altered by any of the agonists. 4 Electrically stimulated contractions of longitudinal muscle in strips of longitudinal muscle-myenteric plexus were not inhibited by DPDPE. Similarly, DPDPE did not significantly inhibit electrically induced contraction of circular muscle in strips of circular muscle-myenteric plexus. 5 Each of the agonist effects on peristaltic parameters was antagonized by the appropriate antagonist:6 It is concluded that J and K agonists act primarily on excitatory circular and longitudinal muscle motor neurones. The 6 agonist probably acts on enteric neurones presynaptic to excitatory circular and longitudinal muscle motor neurones. 7 Antagonists for .t, 6 and K receptors did not affect any parameters of peristalsis when the intestine emptied against a low resistance. However, when emptying against a high outflow resistance, the average power generated by the intestine was increased by the K antagonist, nor-BNI, but not by CTOP or naltrindole. 8 It is concluded that endogenous opioids appear to have little role in peristalsis when the intestine is working against a low outflow resistance. However endogenous opioids, acting primarily at K receptors, provide a braking mechanism by inhibiting the emptying phase of peristalsis in conditions in which the intestine empties against a higher resistance.

show abstract

Opioid Peptides of The Gut

Cited by 17 publications

References 276 publications

Constipation in advanced cancer patients

Constipation in advanced cancer patients

Characterisation of opioid receptors involved in modulating circular and longitudinal muscle contraction in the rat ileum

Modulation of peristalsis in the guinea‐pig isolated small intestine by exogenous and endogenous opioids

Contact Info

Product

Resources

About