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Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse.

Patten GS, Head RJ, Abeywardena MY - Clin Exp Gastroenterol (2011)

Bottom Line: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients.Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.In contrast to naloxone, relatively high oral doses of the μ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Preventative Health National Research Flagship, Adelaide, Australia;

ABSTRACT

Background and aims: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients. The major aims of this study were to: 1) characterize the opioid-specific antagonism of morphine-induced inhibition of electrically driven contraction of the small intestine of mice, rats, and guinea pigs; and 2) test if the oral delivery of small milk-derived opioid antagonist peptides could block morphine-induced inhibition of intestinal transit in mice.

Methods: Mouse, rat, and guinea pig intact ileal sections were electrically stimulated to contract and inhibited with morphine in vitro. Morphine inhibition was then blocked by opioid subtype antagonists in the mouse and guinea pig. Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.

Results: The guinea pig tissue was more sensitive to morphine inhibition compared with the mouse or the rat (IC(50) [half maximal inhibitory concentration] values as nmol/L ± SEM were 34 ± 3, 230 ± 13, and 310 ± 14 respectively) (P < 0.01). The inhibitory influence of opioid agonists (IC(50)) in electrically driven ileal mouse preparations were DADLE ([D-Ala(2), D-Leu(5)]-enkephalin) ≥ met-enkephalin ≥ dynorphin A ≥ DAMGO ([D-Ala(2), N-Me-Phe(4), Glyol(5)]-enkephalin) > morphine > morphiceptin as nmol/L 13.9, 17.3, 19.5, 23.3, 230, and 403 respectively. The mouse demonstrated predominantly κ- and δ-opioid receptor activity with a smaller μ-opioid receptor component. Both mouse and guinea pig tissue were sensitive to casoxin 4 antagonism of morphine inhibition of contraction. In contrast to naloxone, relatively high oral doses of the μ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit.

Conclusions: Casoxin 4 reverses morphine-induced inhibition of contraction in mice and guinea pigs in vitro but fails to influence morphine inhibition of mouse small intestinal transit by the oral route.

No MeSH data available.


Related in: MedlinePlus

Effect of opioid antagonists on morphine inhibition of small intestinal transit in the mouse. The dye front represents the percentage of the total SI that the dye Poly R-478 has traveled. Morphine was injected subcutaneously at the concentrations indicated 20 minutes before the gavage of dye-containing saline as control or CSX 4 (50 mg/kg of bodyweight) or LFX A (50 mg/kg). Total gut transit time was 45 minutes. Results are mean ± SEM, with the number of mice indicated inside the bar. Morphine at 1.0, 1.5, and 2.0 mg/kg significantly inhibited transit (a, ANOVA, P < 0.01) compared with control (0 mg/kg). The corresponding CSX 4 or LFX A-treated mice had SI transit dye fronts that were also significantly different compared with control (b, ANOVA, P < 0.001) but not significantly different from the corresponding morphine dosage treatment alone.Abbreviations: ANOVA, analysis of variance; CSX 4, casoxin 4; LFX A, lactoferroxin A; SEM, standard error of the mean; SI, small intestine.
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f4-ceg-4-023: Effect of opioid antagonists on morphine inhibition of small intestinal transit in the mouse. The dye front represents the percentage of the total SI that the dye Poly R-478 has traveled. Morphine was injected subcutaneously at the concentrations indicated 20 minutes before the gavage of dye-containing saline as control or CSX 4 (50 mg/kg of bodyweight) or LFX A (50 mg/kg). Total gut transit time was 45 minutes. Results are mean ± SEM, with the number of mice indicated inside the bar. Morphine at 1.0, 1.5, and 2.0 mg/kg significantly inhibited transit (a, ANOVA, P < 0.01) compared with control (0 mg/kg). The corresponding CSX 4 or LFX A-treated mice had SI transit dye fronts that were also significantly different compared with control (b, ANOVA, P < 0.001) but not significantly different from the corresponding morphine dosage treatment alone.Abbreviations: ANOVA, analysis of variance; CSX 4, casoxin 4; LFX A, lactoferroxin A; SEM, standard error of the mean; SI, small intestine.

Mentions: We have previously demonstrated that casoxin 4 antagonizes the inhibitory effect of morphine on electrically driven contraction when specifically applied to the lumen of the isolated intact guinea pig ileum.7 In this report we have shown that casoxin 4 also inhibits morphine when added nonspecifically to the serosal side of the mouse ileum. We have further investigated whether casoxin 4 and another milk-derived oligopeptide, lactoferroxin A, a μ-opioid receptor antagonist isolated from the enzymatic digestion of human lactoferrin (H–Tyr–Leu–Gly–Ser–Gly–Tyr–OCH3), can antagonize the morphine inhibition of gut transit in the mouse model.26,27 Morphine doses of 1.0, 1.5, and 2.0 mg/kg (subcutaneous) significantly inhibited the transit of the dye Poly R-478 in the small intestine of the mouse (Figure 4). After 45 minutes transit time, the percentage of Poly R-478 remaining in the stomach for saline control, 1.5 mg/kg, and 2.0 mg/kg morphine, subcutaneous, (number of mice) were: 14.2 ± 2.8 (24), 22.5 ± 2.1 (16) and 31.2 ± 7.8 (6), respectively. There was significant difference between the groups (P = 0.02), with 2.0 mg/kg morphine being significantly higher than saline control (P < 0.05). Casoxin 4 gavaged at 50 mg/kg did not significantly lower the Poly R-478 content of the stomach at the two doses of morphine. Casoxin 4 and lactoferroxin A gavaged at 50 mg/kg with the dye 20 minutes after injection of morphine also failed to significantly overcome the morphine inhibition of small intestinal transit (Figure 4).


Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse.

Patten GS, Head RJ, Abeywardena MY - Clin Exp Gastroenterol (2011)

Effect of opioid antagonists on morphine inhibition of small intestinal transit in the mouse. The dye front represents the percentage of the total SI that the dye Poly R-478 has traveled. Morphine was injected subcutaneously at the concentrations indicated 20 minutes before the gavage of dye-containing saline as control or CSX 4 (50 mg/kg of bodyweight) or LFX A (50 mg/kg). Total gut transit time was 45 minutes. Results are mean ± SEM, with the number of mice indicated inside the bar. Morphine at 1.0, 1.5, and 2.0 mg/kg significantly inhibited transit (a, ANOVA, P < 0.01) compared with control (0 mg/kg). The corresponding CSX 4 or LFX A-treated mice had SI transit dye fronts that were also significantly different compared with control (b, ANOVA, P < 0.001) but not significantly different from the corresponding morphine dosage treatment alone.Abbreviations: ANOVA, analysis of variance; CSX 4, casoxin 4; LFX A, lactoferroxin A; SEM, standard error of the mean; SI, small intestine.
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f4-ceg-4-023: Effect of opioid antagonists on morphine inhibition of small intestinal transit in the mouse. The dye front represents the percentage of the total SI that the dye Poly R-478 has traveled. Morphine was injected subcutaneously at the concentrations indicated 20 minutes before the gavage of dye-containing saline as control or CSX 4 (50 mg/kg of bodyweight) or LFX A (50 mg/kg). Total gut transit time was 45 minutes. Results are mean ± SEM, with the number of mice indicated inside the bar. Morphine at 1.0, 1.5, and 2.0 mg/kg significantly inhibited transit (a, ANOVA, P < 0.01) compared with control (0 mg/kg). The corresponding CSX 4 or LFX A-treated mice had SI transit dye fronts that were also significantly different compared with control (b, ANOVA, P < 0.001) but not significantly different from the corresponding morphine dosage treatment alone.Abbreviations: ANOVA, analysis of variance; CSX 4, casoxin 4; LFX A, lactoferroxin A; SEM, standard error of the mean; SI, small intestine.
Mentions: We have previously demonstrated that casoxin 4 antagonizes the inhibitory effect of morphine on electrically driven contraction when specifically applied to the lumen of the isolated intact guinea pig ileum.7 In this report we have shown that casoxin 4 also inhibits morphine when added nonspecifically to the serosal side of the mouse ileum. We have further investigated whether casoxin 4 and another milk-derived oligopeptide, lactoferroxin A, a μ-opioid receptor antagonist isolated from the enzymatic digestion of human lactoferrin (H–Tyr–Leu–Gly–Ser–Gly–Tyr–OCH3), can antagonize the morphine inhibition of gut transit in the mouse model.26,27 Morphine doses of 1.0, 1.5, and 2.0 mg/kg (subcutaneous) significantly inhibited the transit of the dye Poly R-478 in the small intestine of the mouse (Figure 4). After 45 minutes transit time, the percentage of Poly R-478 remaining in the stomach for saline control, 1.5 mg/kg, and 2.0 mg/kg morphine, subcutaneous, (number of mice) were: 14.2 ± 2.8 (24), 22.5 ± 2.1 (16) and 31.2 ± 7.8 (6), respectively. There was significant difference between the groups (P = 0.02), with 2.0 mg/kg morphine being significantly higher than saline control (P < 0.05). Casoxin 4 gavaged at 50 mg/kg did not significantly lower the Poly R-478 content of the stomach at the two doses of morphine. Casoxin 4 and lactoferroxin A gavaged at 50 mg/kg with the dye 20 minutes after injection of morphine also failed to significantly overcome the morphine inhibition of small intestinal transit (Figure 4).

Bottom Line: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients.Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.In contrast to naloxone, relatively high oral doses of the μ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Preventative Health National Research Flagship, Adelaide, Australia;

ABSTRACT

Background and aims: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients. The major aims of this study were to: 1) characterize the opioid-specific antagonism of morphine-induced inhibition of electrically driven contraction of the small intestine of mice, rats, and guinea pigs; and 2) test if the oral delivery of small milk-derived opioid antagonist peptides could block morphine-induced inhibition of intestinal transit in mice.

Methods: Mouse, rat, and guinea pig intact ileal sections were electrically stimulated to contract and inhibited with morphine in vitro. Morphine inhibition was then blocked by opioid subtype antagonists in the mouse and guinea pig. Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.

Results: The guinea pig tissue was more sensitive to morphine inhibition compared with the mouse or the rat (IC(50) [half maximal inhibitory concentration] values as nmol/L ± SEM were 34 ± 3, 230 ± 13, and 310 ± 14 respectively) (P < 0.01). The inhibitory influence of opioid agonists (IC(50)) in electrically driven ileal mouse preparations were DADLE ([D-Ala(2), D-Leu(5)]-enkephalin) ≥ met-enkephalin ≥ dynorphin A ≥ DAMGO ([D-Ala(2), N-Me-Phe(4), Glyol(5)]-enkephalin) > morphine > morphiceptin as nmol/L 13.9, 17.3, 19.5, 23.3, 230, and 403 respectively. The mouse demonstrated predominantly κ- and δ-opioid receptor activity with a smaller μ-opioid receptor component. Both mouse and guinea pig tissue were sensitive to casoxin 4 antagonism of morphine inhibition of contraction. In contrast to naloxone, relatively high oral doses of the μ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit.

Conclusions: Casoxin 4 reverses morphine-induced inhibition of contraction in mice and guinea pigs in vitro but fails to influence morphine inhibition of mouse small intestinal transit by the oral route.

No MeSH data available.


Related in: MedlinePlus