# Novel cellular markers of drug-mediated calcium signaling in astrocytes

> **NIH NIH R21** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2021 · $217,979

## Abstract

Project Summary
Intracellular Ca2+ dynamics provide one of the primary means of signaling within astrocytes. The significance
of astrocyte Ca2+ signaling includes bidirectional communication with neurons and governance of neural
function through diverse mechanisms including gliotransmission and neurotransmitter transport. Reflecting the
diverse roles for astrocyte Ca2+, there are distinct mechanisms and spatial domains of Ca2+ within the cell
body and peripheral processes. However, despite the substantial evidence for fundamental roles for astrocyte
Ca2+ in the cellular mechanisms of brain function and behavior, it remains largely unknown whether or how
drugs of abuse affect astrocyte Ca2+ signaling. This is a particularly salient question, given the increasing
evidence that astrocytes within the reward circuitry are chronically impaired both in structure and function.
Further, limitations of existing methods of Ca2+ monitoring present significant hurdles toward assessment of
astrocyte Ca2+ elevations associated with behavior in deep brain structures in rat. Toward that challenge, we
have developed two novel AAVs which express the photoconvertible, ratiometric Ca2+ indicator CaMPARI2
under control of the astrocyte-specific GfaABC1D promoter, to allow irreversible marking of Ca2+-activated
astrocytes. One variant is cytosolic and expressed primarily in the cell body, localized to primarily report
somatic Ca2+ elevations; in contrast, the Lck-fusion variant can report Ca2+ elevations throughout the
astrocyte and within the fine peripheral processes. Both variants demonstrate reliable, astrocyte-restricted
expression in the nucleus accumbens, hippocampus and prefrontal cortex, and we have confirmed
photoconversion upon Ca2+ stimulation in live slice. The goal of this proposal is to validate use of these newly
developed tools to quantify astrocyte Ca2+ responses to stimuli in slice and in vivo, and to optimize
parameters for which future studies can be designed to assess astroglial Ca2+ dynamics associated with drug
self-administration and related behaviors. Aim 1 will optimize conditions for astrocyte Ca2+ monitoring in live
slice in response to both ATP and dopamine receptor agonism. Aim 2 will validate and optimize conditions for
Ca2+ monitoring following optical stimulation in vivo coupled with cocaine administration in rat, using an
established experimental design for CaMPARI2 activation in vivo. These studies will inform how both acute
and chronic cocaine exposure regulate Ca2+ dynamics in astrocytes. In both cases, CaMPARI2
photoconversion will be assessed by red:green fluorescence ratios as well as immunohistochemistry using a
custom anti-CaMPARI2-red antibody. Results will allow for applications toward investigation of astrocyte Ca2+
across a broad field of cells, imaged at high resolution and with multiplexed assessment of gene and protein
expression, and for interrogation of functional responsiveness of astrocytes across varied drugs of ab...

## Key facts

- **NIH application ID:** 10104136
- **Project number:** 1R21DA052447-01
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Kathryn Joanna Reissner
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $217,979
- **Award type:** 1
- **Project period:** 2021-03-15 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10104136

## Citation

> US National Institutes of Health, RePORTER application 10104136, Novel cellular markers of drug-mediated calcium signaling in astrocytes (1R21DA052447-01). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10104136. Licensed CC0.

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