Evaluation and comparison of antinociceptive activity of aspartame with sucrose

Evaluation of the effectiveness of sucrose versus xylitol application in minimizing pain related to dental injection in 5-7-year-old children - A randomized controlled pilot study

Background

Oral application of sweet-tasting solutions has found to be effective in minimizing pain on dental injection in children. Xylitol has never been tested in this regard.

Aim

The aim of this study was to compare the effectiveness of prior application of sucrose versus xylitol solution in minimizing pain on dental injection in 5-7-year-old children.

Settings and Design

This study was a randomized controlled clinical trial.

Materials and Methods

Informed consent was taken. A total of 30 children who required maxillary buccal infiltration injection were selected. The children were randomly allocated into the sucrose group, xylitol group, or control group by lottery method. In the sucrose and xylitol groups, 30% sucrose or 30% xylitol solution was applied on the lateral surface of the tongue for 2 min. In the control group, distilled water was applied. In all the groups, the topical anesthetic was applied at the site of injection followed by buccal infiltration. A video was taken during injection, and the sound eye-motor (SEM) scale was recorded by a blinded examiner. Patients were asked to self-evaluate using the Wong-Baker Faces Pain Scale (WBFPS).

Statistical Analysis

Mann-Whitney test was used to analyze the data.

Results

There was a statistically significant difference in the WBFPS and the SEM score between the sucrose and the control group (P < 0.05) and the xylitol and control group (P < 0.05). No statistically significant difference was found between the sucrose and xylitol group.

Conclusion

The application of xylitol solution before dental injection was as effective as sucrose solution in minimizing pain during the injection.

In vivo anti-arthritic and anti-nociceptive effects of ethanol extract of Moringa oleifera leaves on complete Freund's adjuvant (CFA)-induced arthritis in rats

Background

The medicinal uses of plants are in many cases based exclusively on traditional knowledge without enough scientific evidences. Different parts of Moringa oleifera were traditionally used for the treatment of wide variety of ailments including arthritis and joints pain. The present study had been designed to evaluate the anti-arthritic and anti-nociceptive activities of ethanol extract of Moringa leaves, this being the most abundant plant part suitable for commercial mass production of botanical medicinal products.

Methods

Complete Freund's adjuvant (CFA)-induced arthritis in rats was used as disease model. CFA-induced inflammatory paw edema, body weight, arthritic index, X-ray radiography, hematological parameters, and walk track and locomotion analysis were all evaluated for the assessment of disease progression. In addition to that, anti-nociceptive activity was examined at different dose levels in both normal and arthritic-induced rats using Eddy's hot plate and tail flick thermal analgesia.

Results

The analysis of various arthritic assessment parameters used in this study revealed that Moringa extract has a considerable effect in preventing development or ameliorate arthritis disease severity. Moreover, the ethanol extract of Moringa leaves revealed significant anti-nociceptive activity at in both normal and CFA-induced arthritis rats in a dose-dependent manner.

Conclusion

Ethanol extract of Moringa leaves appears to be a really promising as analgesic and arthritis medication, but a larger and more detailed preclinical and clinical studies especially in human is highly recommended.

Novel κ-opioid receptor agonist MB-1C-OH produces potent analgesia with less depression and sedation

AIM

To characterize the pharmacological profiles of a novel κ-opioid receptor agonist MB-1C-OH.

METHODS

[(3)H]diprenorphine binding and [(35)S]GTPγS binding assays were performed to determine the agonistic properties of MB-1C-OH. Hot plate, tail flick, acetic acid-induced writhing, and formalin tests were conducted in mice to evaluate the antinociceptive actions. Forced swimming and rotarod tests of mice were used to assess the sedation and depression actions.

RESULTS

In [(3)H]diprenorphine binding assay, MB-1C-OH did not bind to μ- and δ-opioid receptors at the concentration of 100 μmol/L, but showed a high affinity for κ-opioid receptor (Ki=35 nmol/L). In [(35)S]GTPγS binding assay, the compound had an Emax of 98% and an EC50 of 16.7 nmol/L for κ-opioid receptor. Subcutaneous injection of MB-1C-OH had no effects in both hot plate and tail flick tests, but produced potent antinociception in the acetic acid-induced writhing test (ED50=0.39 mg/kg), which was antagonized by pretreatment with a selective κ-opioid receptor antagonist Nor-BNI. In the formalin test, subcutaneous injection of MB-1C-OH did not affect the flinching behavior in the first phase, but significantly inhibited that in the second phase (ED50=0.87 mg/kg). In addition, the sedation or depression actions of MB-1C-OH were about 3-fold weaker than those of the classical κ agonist (-)U50,488H.

CONCLUSION

MB-1C-OH is a novel κ-opioid receptor agonist that produces potent antinociception causing less sedation and depression.

Antinociceptive actions of peripheral glucose administration

The effects of intraperitoneal (ip) D-glucose administration on antinociception were studied in male Long-Evans rats. Rats were assessed for antinociception using the hot-water tail-withdrawal procedure (54±0.2 °C) to determine if peripheral administration of D-glucose (300, 560, or 720 mg/kg) would enhance morphine-mediated antinociception (MMA) (1.0, 3.0, 4.2, 5.6, and 10.0mg/kg cumulative-dosing regime) and if D-glucose (560, 720, or 1000 mg/kg) alone could produce antinociceptive activity that was naloxone (0.32 mg/kg) reversible. Additionally, the actions of D-glucose on MMA were compared with a stereoisomer, L-glucose, which is not metabolized. The results of these studies demonstrate that peripheral administration of D-glucose significantly enhances MMA and that D-glucose alone produces antinociceptive actions that are potentially mediated by the endogenous opioid system. Furthermore, L-glucose failed to have an effect on MMA suggesting that the alterations in antinociception seen with D-glucose are not due to stressors such as osmolality or injection. The current studies provide evidence that D-glucose alteration of antinociception is not simply a response to taste or gustation.

Endogenous opiates and behavior: 2012

This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).