Dopamine enhancement of dextrorphan-induced skin antinociception in response to needle pinpricks in rats

Naphazoline and oxymetazoline are superior to epinephrine in enhancing the cutaneous analgesia of lidocaine in rats

This study observed the cutaneous analgesic effect of adrenergic agonists when combined with lidocaine. We aimed at the usefulness of four adrenergic agonists and epinephrine as analgesics or as tools to prolong the effect of local anesthetics using a model of cutaneous trunci muscle reflex (pinprick pain) in rats. We showed that subcutaneous four adrenergic agonists and epinephrine, as well as the local anesthetic bupivacaine and lidocaine, developed a concentration-dependent cutaneous analgesia. The rank order of the efficacy of different compounds (ED₅₀ ; median effective dose) was epinephrine [0.013 (0.012-0.014) μmol] > oxymetazoline [0.25 (0.22-0.28) μmol] > naphazoline [0.42 (0.34-0.53) μmol] = bupivacaine [0.43 (0.37-0.50) μmol] > xylometazoline [1.34 (1.25-1.45) μmol] > lidocaine [5.86 (5.11-6.72) μmol] > tetrahydrozoline [6.76 (6.21-7.36) μmol]. The duration of full recovery caused by tetrahydrozoline, oxymetazoline, or xylometazoline was greater (P < 0.01) than that induced via epinephrine, bupivacaine, lidocaine, or naphazoline at equianesthetic doses (ED₂₅ , ED₅₀ , and ED₇₅ ). Co-administration of lidocaine (ED₅₀ ) with four adrenergic agonists or epinephrine enhanced the cutaneous analgesic effect. We observed that four adrenergic agonists and epinephrine induce analgesia by themselves, and such an effect has a longer duration than local anesthetics. Co-administration of lidocaine with the adrenergic agonist enhances the analgesic effect, and the cutaneous analgesic effect of lidocaine plus naphazoline (or oxymetazoline) is greater than that of lidocaine plus epinephrine.

N(Omega)-nitro-l-arginine methyl ester potentiates lidocaine analgesic and anaesthetic effect in rats

OBJECTIVES

The purpose of the experiment was to study the effect of L-NAME (N(Omega)-nitro-L-arginine methyl ester) and its cotreatment with lidocaine on the spinal block and infiltrative cutaneous analgesia.

METHODS

The quality of cutaneous analgesia was examined by the block of the cutaneous trunci muscle reflexes following needle stimuli in the rat. Spinal anaesthetic potency was assessed by measuring three neurobehavioral examinations of nociceptive, proprioceptive and motor function following intrathecal injection in the rat.

KEY FINDINGS

L-NAME (0.6, 6 and 60 nmol) when cotreatment with lidocaine (ED50) produced dose-related cutaneous analgesia. Coadministration of L-NAME (0.6 μmol) with lidocaine intensified (P < 0.01) and prolonged (P < 0.001) cutaneous analgesia, whereas subcutaneous L-NAME (0.6 μmol) and saline did not provoke cutaneous analgesic effects. Adding L-NAME (2.5 μmol) to lidocaine intrathecally prolonged spinal sensory and motor block (P < 0.01), while intrathecal L-NAME (2.5 μmol) or 5% dextrose (vehicle) produced no spinal block.

CONCLUSIONS

L-NAME at 60 nmol (the minimum effective dose) increases and prolongs the effect of cutaneous analgesia of lidocaine. L-NANE at an ineffective dose potentiates lidocaine analgesic and anaesthetic effects.

Metabolomics of Esophageal Squamous Cell Carcinoma Tissues: Potential Biomarkers for Diagnosis and Promising Targets for Therapy

Background

The incidence of esophageal squamous cell carcinoma in China ranks first in the world. The early diagnosis technology is underdeveloped, and the prognosis is poor, which seriously threatens the quality of life of the Chinese people. Epidemiological findings are related to factors such as diet, living habits, and age. The specific mechanism is not clear yet. Metabolomics is a kind of omics that simultaneously and quantitatively analyzes the comprehensive profile of metabolites in living systems. It has unique advantages in the study of the diagnosis and pathogenesis of tumor-related diseases, especially in the search for biomarkers. Therefore, it is desirable to perform metabolic profiling analysis of cancer tissues through metabolomics to find potential biomarkers for the diagnosis and treatment of esophageal squamous cell carcinoma.

Methods

HPLC-TOF-MS/MS technology and Illumina Hiseq Xten Sequencing was used for the analysis of 210 pairs of matched esophageal squamous cell carcinoma tissues and normal tissues in Zhenjiang City, Jiangsu Province, a high-incidence area of esophageal cancer in China. Bioinformatics analysis was also performed.

Results

Through metabolomic and transcriptomic analysis, this study found that a total of 269 differential metabolites were obtained in esophageal squamous cell carcinoma and normal tissues, and 48 differential metabolic pathways were obtained through KEGG enrichment analysis. After further screening and identification, 12 metabolites with potential biomarkers to differentiate esophageal squamous cell carcinoma from normal tissues were obtained.

Conclusions

From the metabolomic data, 4 unknown compounds were found to be abnormally expressed in esophageal squamous cell carcinoma for the first time, such as 9,10-epoxy-12,15-octadecadienoate; 3 metabolites were found in multiple abnormal expression in another tumor, but upregulation or downregulation was found for the first time in esophageal cancer, such as oleoyl glycine; at the same time, it was further confirmed that five metabolites were abnormally expressed in esophageal squamous cell carcinoma, which was similar to the results of other studies, such as PE.

Antimalarial primaquine for skin infiltration analgesia in rats

OBJECTIVES

The purpose of this study was to estimate the ability of antimalarial medications to induce local infiltration analgesia.

METHODS

Using a rat model of skin infiltration anaesthesia, the effects of antimalarial medications (primaquine, chloroquine, hydroxychloroquine and amodiaquine) were compared with the application of lidocaine.

KEY FINDINGS

At a dose of 3 μmol, primaquine and chloroquine displayed better potency (all P < 0.05) and greater duration (all P < 0.01) of cutaneous analgesia than lidocaine, whereas the other antimalarial medications showed a similar potency and duration of cutaneous analgesia when compared with lidocaine. When a dose of 3 μmol antimalarial medication was used, primaquine was the most potent and had the longest duration of action among four antimalarial medications. The relative potency ranking (ED50, 50% effective dose) has been found to be primaquine [2.10 (1.87 - 2.37) μmol] > lidocaine [6.27 (5.32 -7.39) μmol] (P < 0.01). Infiltration analgesia of skin with primaquine had a greater duration of action than did lidocaine on the equipotent (ED25, ED50, ED75) basis (P < 0.01).

CONCLUSIONS

Primaquine and chloroquine have greater potency and longer lasting skin analgesia when compared with lidocaine, while the other antimalarials display a similar potency in comparison with lidocaine.

Chlorpheniramine produces cutaneous analgesia in rats

BACKGROUND

This study sought to assess the cutaneous (peripheral) analgesic effects of antihistamine chlorpheniramine, compared with the long-lasting local anesthetic bupivacaine.

METHODS

After chlorpheniramine and bupivacaine were subcutaneously injected under the dorsal skin of the rats, the cutaneous analgesia effect was quantitatively evaluated by scoring the number to which the animal failed to react (cutaneous trunci muscle reflex). The quality and duration of chlorpheniramine and bupivacaine on infiltrative cutaneous analgesia were compared.

RESULTS

We revealed that subcutaneous chlorpheniramine, as well as the local anesthetic bupivacaine elicited cutaneous analgesia in a dosage-dependent manner. Based on their ED₅₀s (50% effective doses), the relative potency was found to be chlorpheniramine [1.13 (1.05-1.22) μmol] < bupivacaine [0.52 (0.46-0.58) μmol] (p < 0.01). When comparing the ED₂₅s, ED₅₀s and ED₇₅s, full recovery time induced by chlorpheniramine was longer (p < 0.01) than that induced by bupivacaine.

CONCLUSIONS

Our preclinical data demonstrated that both chlorpheniramine and bupivacaine dose-dependently provoked the cutaneous analgesic effects. Chlorpheniramine with a more prolonged duration was less potent than bupivacaine in inducing cutaneous analgesia.

Chloroquine for prolonged skin analgesia in rats

The purpose of this study was to investigate the ability of chloroquine and chloroquine in combination with vasoconstrictor epinephrine to act as a local anesthetic in skin analgesia. After subcutaneous injection of drugs in rats, the inhibition of the cutaneous trunci muscle reflex (CTMR) is designed for evaluation of the cutaneous analgesic effect. The analgesic effect of chloroquine was compared with that of bupivacaine or coadministration of chloroquine and epinephrine. Chloroquine produced exactly the same local anesthesia as bupivacaine did in a dose-dependent manner. On the ED₅₀ (50 % effective dose) basis, the analgesic potency was chloroquine (4.81 [4.45-5.20] μmol) < bupivacaine (0.46 [0.40‒0.52] μmol) (p <  0.01). At every equipotent dose tested (ED₂₅, ED₅₀ and ED₇₅), chloroquine had a longer duration of cutaneous analgesia than bupivacaine (p <  0.01). Epinephrine enhanced the potency and duration of chloroquine-induced cutaneous analgesia. We found that chloroquine and bupivacaine elicit dose-dependent cutaneous analgesia. Chloroquine is not as potent as bupivacaine, but acts as an infiltrative anesthetic for a longer duration of time and is more potent and effective when used in combination with epinephrine.

Isobologram Analysis: A Comprehensive Review of Methodology and Current Research

Drug combination is a common method for clinical disease treatment. Whether the combination of drugs is reasonable often affects the result of the disease treatment. Many methods have been used to evaluate interaction between drugs to date. Isobologram analysis has been mathematically proven and widely used to evaluate drug interactions. In this paper, the principle of isobologram analysis and its application in drug interaction evaluation are summarized. The applications of the similar cotoxicity coefficient and fractional inhibitory concentration index in the evaluation of drug interaction are also reviewed. This work is expected to evaluate the effect of formulations scientifically and provide scientific judgment standards for the development of formulations and clinical drug compatibility.