Related Experiment Video
Updated: Jun 25, 2025
Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Loss of ATP-Sensitive Potassium Channel Expression and Function in the Nervous System Decreases Opioid Sensitivity in
Cole Fisher1, Kayla Johnson1, Madelyn Moore1
1Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN.
Abstract:
During diabetes progression, β-cell dysfunction due to loss of potassium channels sensitive to ATP, known as KATP channels, occurs, contributing to hyperglycemia. The aim of this study was to investigate if KATP channel expression or activity in the nervous system was altered in a high-fat diet (HFD)-fed mouse model of diet-induced obesity. Expression of two KATP channel subunits, Kcnj11 (Kir6.2) and Abcc8 (SUR1), were decreased in the peripheral and central nervous system of mice fed HFD, which was significantly correlated with mechanical paw-withdrawal thresholds. HFD mice had decreased antinociception to systemic morphine compared with control diet (CON) mice, which was expected because KATP channels are downstream targets of opioid receptors. Mechanical hypersensitivity in HFD mice was exacerbated after systemic treatment with glyburide or nateglinide, KATP channel antagonists clinically used to control blood glucose levels. Upregulation of SUR1 and Kir6.2, through an adenovirus delivered intrathecally, increased morphine antinociception in HFD mice. These data present a potential link between KATP channel function and neuropathy during early stages of diabetes. There is a need for increased knowledge of how diabetes affects structural and molecular changes in the nervous system, including ion channels, to lead to the progression of chronic pain and sensory issues.
Insights
High-fat diets impair KATP channel function in the nervous system, worsening pain sensitivity and reducing morphine effectiveness in mice. Restoring these channels may alleviate diabetic neuropathy.
Area of Science:
- Neuroscience
- Metabolic Disorders
- Molecular Biology
Background:
- Diabetes progression involves beta-cell dysfunction and hyperglycemia.
- ATP-sensitive potassium (KATP) channels are crucial for beta-cell function.
- Neuropathy is a common complication of diabetes, leading to chronic pain.
Purpose of the Study:
- To investigate alterations in KATP channel expression and activity in the nervous system of mice fed a high-fat diet (HFD).
- To explore the role of KATP channels in HFD-induced mechanical hypersensitivity and altered antinociception.
- To determine if modulating KATP channel function can impact pain perception and opioid response in a model of diet-induced obesity.
Main Methods:
- Utilized a high-fat diet (HFD) mouse model to induce obesity and investigate metabolic changes.
- Assessed the expression of KATP channel subunits (Kcnj11/Kir6.2 and Abcc8/SUR1) in the peripheral and central nervous systems.
- Evaluated mechanical paw-withdrawal thresholds and antinociception to systemic morphine.
- Administered KATP channel antagonists (glyburide, nateglinide) and used viral vectors for gene upregulation (SUR1, Kir6.2) via intrathecal delivery.
Main Results:
- HFD-fed mice exhibited decreased expression of KATP channel subunits (Kir6.2 and SUR1) in the nervous system.
- Reduced KATP channel expression correlated with decreased mechanical paw-withdrawal thresholds.
- HFD mice showed diminished antinociception to morphine, which was exacerbated by KATP channel antagonists.
- Intrathecal upregulation of SUR1 and Kir6.2 restored morphine antinociception in HFD mice.
Conclusions:
- KATP channel dysfunction in the nervous system is associated with mechanical hypersensitivity and impaired opioid analgesia in diet-induced obesity.
- These findings suggest a link between KATP channel function and the development of neuropathy in early diabetes stages.
- Further research is needed to understand how diabetes-related changes in ion channels contribute to chronic pain and sensory deficits.
Related Concept Videos
01:25Analgesia and Pain Management
01:22Opioid Receptors: Overview