Ca[sup]2+ excitability of glia to neuromodulator octopamine in Drosophila living brain is greater than that of neurons

Černe, Urška (author), Horvat, Anemari (author), Sanjković, Ena (author), Kozoderc, Nika (author), Kreft, Marko (author), Zorec, Robert (author), Scholz, Nicole (author), Vardjan, Nina (author)

Aim: Octopamine in the Drosophila brain has a neuromodulatory role similar to that of noradrenaline in mammals. After release from Tdc2 neurons, octopamine/tyramine may trigger intracellular Ca2+ signaling via adrenoceptor-like receptors on neural cells, modulating neurotransmission. Octopamine/tyramine receptors are expressed in neurons and glia, but how each of these cell types responds to octopamine remains elusive. This study aimed to characterize Ca2+ responses of neurons and astrocytes to neuromodulatory octopamine signals. Methods: We expressed Ca2+ indicator jGCaMP7b in specific cell type in adult Drosophila brains and performed intracellular Ca2+ imaging in the brain optic lobes upon bath application of octopamine by confocal microscopy. Results: Octopamine-stimulated Ca2+ responses in neurons were different from those of glial cells. The amplitude of octopamine-mediated Ca2+ signals in neurons was 3.4-fold greater than in astrocytes. However, astrocytes were more sensitive to octopamine; the median effective concentration that triggered Ca2+ responses was nearly 6-fold lower in astrocytes than in neurons. In both cell types, Ca2+ transients are shaped by Gq and Gs protein-coupled octopamine/tyramine receptors. Our snRNA-seq database screening uncovered differential expression patterns of these receptors between brain cell types, which may explain the difference in Ca2+ signaling. Conclusion: In the brain optic lobes, astrocytes, not neurons, appear to be the sole responders to low concentration octopamine signals, and therefore likely drive synaptic plasticity and visual processing. Given the interconnectivity of the optic lobes with other brain regions, octopaminergic signals acting through the optic lobe astrocytes may also influence higher-order brain functions including learning and memory.

• Language: English
• Keywords: Drosophila, Ca2+ excitability, astrocytes, neuromodulator, neurons, octopamine, stress response
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 16 str.
• Numbering: Vol. 241, iss. 2, art. e14270
• PID: 20.500.12556/RUL-184251
• UDC: 616-092
• ISSN on article: 1748-1716
• DOI: 10.1111/apha.14270
• COBISS.SI-ID: 223648003
• Publication date in RUL: 02.07.2026

Record is a part of a journal

• Title: Acta physiologica
• Publisher: Wiley & Sons
• ISSN: 1748-1716
• COBISS.SI-ID: 2917396

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: drozofila, Ca2+ ekscitabilnost, astrociti, nevromodulator, nevroni, oktopamin, odziv na stres