# Regulation of Supraoptic Oxytocin Neurons by Oxytocin Receptor Expressing Neurons in the Perinuclear Zone of the Hypothalamus

> **NIH NIH R21** · LOUISIANA STATE UNIV A&M COL BATON ROUGE · 2020 · $176,600

## Abstract

Project Summary / Abstract
The purpose of this research is to characterize the autoregulatory mechanism of the hypothalamic oxytocin
(OT) system on the systemic release of OT during reproductive states. OT is synthesized by magnocellular
cells (MNCs) in the supraoptic (SON) and paraventricular nuclei. OT is released into the general circulation to
induce uterine contraction during parturition and contraction of mammary glands during milk ejection. The
release of OT is, therefore, essential for birth and normal growth of offspring. The systemic release of OT is
largely regulated by the somato-dendritic release of OT that is elicited by physiological stimuli, such as
parturition and suckling. The somato-dendritic release OT on OT MNCs is thought to be mediated by the OT
receptor (OTR) on OT MNCs themselves via an autocrine-paracrine mechanism. Despite this commonly
accepted notion, our preliminary study using OTR reporter mice found no OTR in OT MNCs in the SON;
however, OTR was found in non-OT cells in the perinuclear zone (PNZ), the area immediately dorsal to the
SON. Moreover, these OTR cells have processes projecting into the SON. Based upon reports in the literature
and our preliminary results, we hypothesize that: 1) OTR cells in the PNZ are GABAergic interneurons for OT
MNCs in the SON; and 2) GABA inputs from OTR cells become stimulatory due to increase in intracellular
chloride concentration in OT MNCs in lactating females. We will use an integrative multidisciplinary approach
that includes electrophysiology combined with chemogenetic manipulation of neural activity, neural tracing,
immunocytochemistry on transgenic mouse models to explicitly test our hypotheses. The findings from these
studies will provide new information concerning the regulation of OT release and the neural adaptations that
are necessary for proper parturition and lactation.

## Key facts

- **NIH application ID:** 9840493
- **Project number:** 5R21HD097565-02
- **Recipient organization:** LOUISIANA STATE UNIV A&M COL BATON ROUGE
- **Principal Investigator:** RYOICHI TERUYAMA
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $176,600
- **Award type:** 5
- **Project period:** 2019-01-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9840493

## Citation

> US National Institutes of Health, RePORTER application 9840493, Regulation of Supraoptic Oxytocin Neurons by Oxytocin Receptor Expressing Neurons in the Perinuclear Zone of the Hypothalamus (5R21HD097565-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9840493. Licensed CC0.

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