# Compartmental, rhythmic and plastic neuropeptide release

> **NIH NIH R01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2024 · $772,484

## Abstract

Neuropeptides are crucial in development and for a wide variety of behaviors including circadian rhythms and
sleep. This project has been using imaging to study synaptic neuropeptide release. For example, a new optical
method based on a fluorogen activating protein (FAP) has shown that activity-evoked synaptic neuropeptide
release occurs solely via fusion pores formed by kiss and run exocytosis. These experiments also established
that synaptic fusion pores open spontaneously at a low rate, thereby providing a basis for resting peptidergic
transmission. Furthermore, FAP imaging in the brain showed that Drosophila clock neurons release
neuropeptides daily with different rhythms from terminals and the soma. This differential timing is based on the
use of independent triggers: synaptic release requires Ca2+ influx as expected for release induced by electrical
activity, but somatic release is mediated by the biochemical signal IP3. Remarkably, perturbing the somatic
release mechanism alters specific features of circadian behavior and sleep. Thus, spatially and temporally
partitioned neuropeptide release controls rhythmic behaviors. In parallel, GFP-tagged neuropeptide imaging
led to the discovery of regulation of neuropeptide packaging by tyrosine phosphatases and new insights into
neuropeptide delivery, capture and release at synapses. Finally, G-protein coupled receptor GPCR activation-
based (GRAB) fluorescence sensors have been incorporated into our research to provide a new approach for
resolving release and the subsequent spread of neuropeptides in the brain. Here the above optical tools will be
used with Drosophila genetics to answer three questions posed by prior work on this project:
(a) How is daily IP3 signaling induced in clock neurons and coupled to somatic neuropeptide release and
regulation of rhythmic behaviors?
(b) How does multi-compartmental fusion pore opening and dilation orchestrate neuropeptide release at
native release sites?
(c) How are neuropeptide packaging, axonal transport and synaptic capture controlled to support
neuropeptide stores in release sites undergoing morphological plasticity (i.e., as occurs daily in clock neurons
and in motor neuron axonal arbors in response to retrograde signaling)?
These studies will reveal how surprising signaling-induced neuropeptide release from the soma participates the
peptidergic connectome. Furthermore, in vivo imaging will elucidate the process of neuropeptide release by
fusion pores. Finally, the cell biology underlying the support of peptidergic transmission during plasticity will be
determined for the first time. Thus, this project will yield fundamental insights into neuropeptide release and the
control of behavior, which are critical to the operation of the nervous system.

## Key facts

- **NIH application ID:** 10863945
- **Project number:** 5R01NS032385-28
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** EDWIN S LEVITAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $772,484
- **Award type:** 5
- **Project period:** 1995-08-04 → 2027-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10863945

## Citation

> US National Institutes of Health, RePORTER application 10863945, Compartmental, rhythmic and plastic neuropeptide release (5R01NS032385-28). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10863945. Licensed CC0.

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