# Cortical-Medullary Circuitry Preventing the Cardiovascular Consequences of Chronic Stress

> **NIH NIH R01** · COLORADO STATE UNIVERSITY · 2022 · $256

## Abstract

Summary
 Cardiovascular disease is the leading cause of death worldwide. Prolonged psychosocial stress is a
significant predictor of disease incidence and severity. However, the specific neural mechanisms that
contribute to the cardiovascular consequences of stress are largely unknown. Therefore, the current proposal
will explore how the cortical circuits responsible for cognitive appraisal of stress inhibit physiological stress
responses. Recent studies in rats identified a population of cells in the infralimbic (IL) region of the medial
prefrontal cortex that reduce endocrine and autonomic responses to chronic stress. Further, knockdown of
glutamate release from IL neurons leads to vascular dysfunction after chronic stress. While the activity of
excitatory IL projection neurons is critical for preventing the deleterious effects of chronic stress, the pathways
used by these cells to limit reactivity of autonomic and endocrine effectors remain to be determined.
Preliminary data indicate that the IL projects to catecholaminergic (epinephrine/norepinephrine producing)
neurons in the ventrolateral medulla (VLM), the primary site of sympathetic activation. These excitatory IL
projections also target inhibitory GABAergic and glycinergic neurons within the VLM, leading to the hypothesis
that IL glutamatergic signaling to the VLM limits cardiovascular and endocrine stress reactivity and the
consequences of chronic stress on vascular stiffness and cardiac hypertrophy. This hypothesis will be tested
by optogenetic activation of IL synapses in the VLM during stress exposure in male and female rats. This
approach will be employed in animals that have been previously exposed to chronic variable stress or
remained as unstressed controls. Cardiovascular telemetry will be used to measure heart rate, blood pressure,
and sympathetic activity. A separate aim will examine neuroendocrine stress responses of the hypothalamic-
pituitary-adrenal axis. To determine how IL inputs to the VLM impact pathological responses to chronic stress,
a combinatorial viral approach will be used to retrogradely silence the IL-VLM circuit with Cre-dependent
tetanus toxin. Vascular stiffness, cardiac hypertrophy, and endothelial function will be assessed in male and
female rats exposed to chronic stress. This circuit silencing approach will also be used to examine the
importance of IL signaling for preventing chronic stress effects on the expression of cellular signaling genes in
the VLM. Collectively, these experiments will determine specific circuit and cellular pathways linking cognitive
appraisal and physiological stress responses. Further, this connection represents a critical biological process
that could be harnessed to intervene in the cardiovascular consequences of chronic stress.

## Key facts

- **NIH application ID:** 10532021
- **Project number:** 3R01HL150559-03S1
- **Recipient organization:** COLORADO STATE UNIVERSITY
- **Principal Investigator:** Brent Philip Myers
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $256
- **Award type:** 3
- **Project period:** 2019-12-16 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10532021

## Citation

> US National Institutes of Health, RePORTER application 10532021, Cortical-Medullary Circuitry Preventing the Cardiovascular Consequences of Chronic Stress (3R01HL150559-03S1). Retrieved via AI Analytics 2026-06-14 from https://api.ai-analytics.org/grant/nih/10532021. Licensed CC0.

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