µ-Opioid Receptor Activation Reduces Glutamate Release in the PreBötzinger Complex in Organotypic Slice Cultures
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µ-Opioid Receptor Activation Reduces Glutamate Release in the PreBötzinger Complex in Organotypic Slice Cultures. / Jørgensen, Anders B.; Rasmussen, Camilla Mai; Rekling, Jens C.
In: Journal of Neuroscience, Vol. 42, No. 43, 2022, p. 8066-8077.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - µ-Opioid Receptor Activation Reduces Glutamate Release in the PreBötzinger Complex in Organotypic Slice Cultures
AU - Jørgensen, Anders B.
AU - Rasmussen, Camilla Mai
AU - Rekling, Jens C.
PY - 2022
Y1 - 2022
N2 - The inspiratory rhythm generator, located in the brainstem preBotzinger complex (preBotC), is dependent on glutamatergic signaling and is affected profoundly by opioids. Here, we used organotypic slice cultures of the newborn mouse brainstem of either sex in combination with genetically encoded sensors for Ca2+, glutamate, and GABA to visualize Ca2+, glutamatergic and GABAergic signaling during spontaneous rhythm and in the presence of DAMGO. During spontaneous rhythm, the glutamate sensor SF-iGluSnFR.A184S revealed punctate synapse-like fluorescent signals along dendrites and somas in the preBotC with decay times that were prolonged by the glutamate uptake blocker (TFB-TBOA). The GABA sensor iGABASnFR showed a more diffuse fluorescent signal during spontaneous rhythm. Rhythmic Ca2+- and glutamate transients had an inverse relationship between the spontaneous burst frequency and the burst amplitude of the Ca2+ and glutamate signals. A similar inverse relationship was observed when bath applied DAMGO reduced spontaneous burst frequency and increased the burst amplitude of Ca2+, glutamate, and GABA transient signals. However, a hypoxic challenge reduced both burst frequency and Ca2+ transient amplitude. Using a cocktail that blocked glutamatergic, GABAergic, and glycinergic transmission to indirectly measure the release of glutamate/GABA in response to an electrical stimulus, we found that DAMGO reduces the release of glutamate in the preBotC but has no effect on GABA release. This suggest that the opioid mediated slowing of respiratory rhythm involves presynaptic reduction of glutamate release, which would impact the ability of the network to engage in recurrent excitation, and may result in the opioid-induced slowing of inspiratory rhythm.
AB - The inspiratory rhythm generator, located in the brainstem preBotzinger complex (preBotC), is dependent on glutamatergic signaling and is affected profoundly by opioids. Here, we used organotypic slice cultures of the newborn mouse brainstem of either sex in combination with genetically encoded sensors for Ca2+, glutamate, and GABA to visualize Ca2+, glutamatergic and GABAergic signaling during spontaneous rhythm and in the presence of DAMGO. During spontaneous rhythm, the glutamate sensor SF-iGluSnFR.A184S revealed punctate synapse-like fluorescent signals along dendrites and somas in the preBotC with decay times that were prolonged by the glutamate uptake blocker (TFB-TBOA). The GABA sensor iGABASnFR showed a more diffuse fluorescent signal during spontaneous rhythm. Rhythmic Ca2+- and glutamate transients had an inverse relationship between the spontaneous burst frequency and the burst amplitude of the Ca2+ and glutamate signals. A similar inverse relationship was observed when bath applied DAMGO reduced spontaneous burst frequency and increased the burst amplitude of Ca2+, glutamate, and GABA transient signals. However, a hypoxic challenge reduced both burst frequency and Ca2+ transient amplitude. Using a cocktail that blocked glutamatergic, GABAergic, and glycinergic transmission to indirectly measure the release of glutamate/GABA in response to an electrical stimulus, we found that DAMGO reduces the release of glutamate in the preBotC but has no effect on GABA release. This suggest that the opioid mediated slowing of respiratory rhythm involves presynaptic reduction of glutamate release, which would impact the ability of the network to engage in recurrent excitation, and may result in the opioid-induced slowing of inspiratory rhythm.
KW - GABA
KW - genetically -encoded sensors
KW - iGluSnFR
KW - opioids
KW - respiration
KW - PRE-BOTZINGER COMPLEX
KW - RESPIRATORY NETWORK
KW - POTASSIUM CHANNELS
KW - BRAIN-STEM
KW - NEURONS
KW - INTERNEURONS
KW - GENERATION
KW - DEPRESSION
KW - MODULATION
U2 - 10.1523/JNEUROSCI.1369-22.2022
DO - 10.1523/JNEUROSCI.1369-22.2022
M3 - Journal article
C2 - 36096669
VL - 42
SP - 8066
EP - 8077
JO - The Journal of neuroscience : the official journal of the Society for Neuroscience
JF - The Journal of neuroscience : the official journal of the Society for Neuroscience
SN - 0270-6474
IS - 43
ER -
ID: 326792864