Opioid-Mediated Astrocyte–Neuron Signaling in the Nucleus Accumbens

• Main Authors: Michelle Corkrum, Patrick E. Rothwell, Mark J. Thomas, Paulo Kofuji, Alfonso Araque
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Cells
• Subjects: astrocytes; opioids; synaptic transmission
• Online Access: https://www.mdpi.com/2073-4409/8/6/586

Major hallmarks of astrocyte physiology are the elevation of intracellular calcium in response to neurotransmitters and the release of neuroactive substances (gliotransmitters) that modulate neuronal activity. While μ-opioid receptor expression has been identified in astrocytes of the nucleus accumbens, the functional consequences on astrocyte−neuron communication remains largely unknown. The present study has investigated the astrocyte responsiveness to μ-opioid signaling and the regulation of gliotransmission in the nucleus accumbens. Through the combination of calcium imaging and whole-cell patch clamp electrophysiology in brain slices, we have found that μ-opioid receptor activation in astrocytes elevates astrocyte cytoplasmic calcium and stimulates the release of the gliotransmitter glutamate, which evokes slow inward currents through the activation of neuronal N-methyl-D-aspartate (NMDA) receptors. These results indicate the existence of molecular mechanisms underlying opioid-mediated astrocyte−neuron signaling in the nucleus accumbens.