# The Human Cardiovascular Control: The Role of Limb Veins

> **NIH NIH R01** · PENNSYLVANIA STATE UNIV HERSHEY MED CTR · 2021 · $533,395

## Abstract

Project Summary/Abstract
In this project, we examine the role venous distention plays in the reflex regulation of blood pressure. Our prior
work in humans demonstrates that vascular distension of peripheral limb veins evokes a powerful
sympathoexcitatory reflex (venous distension reflex, VDR) that raises blood pressure. In this proposal, we have
three specific aims: 1) we will determine the role played by cyclooxygenase metabolites of arachidonic acid in
evoking the VDR, and examine how prostaglandins mediate their effects on the VDR in humans. Based on our
supportive pilot data, we hypothesize that acute blockade of cyclooxygenase enzyme system will markedly
attenuate muscle sympathetic nerve activity (MSNA) and arterial pressure responses to limb venous distention;
2) we will examine the hypothesis that limb venous distension increases the gain and resets the operating
point of the baroreflex system in healthy subjects. We speculate that these changes in the gain and operating
point of the baroreflex can buffer blood pressure changes during orthostatic challenge; We will also examine if
the interaction between VDR and baroreflex differs in males and females; and 3) we will examine the role VDR
plays in maintaining blood pressure during orthostatic stress in human subjects. We hypothesize that the
strength of the VDR and/or the interaction between the VDR and the baroreflex will be related to orthostatic
tolerance. We also hypothesize that individuals with “orthostatic hypertension” will have a heightened VDR. We
further speculate that maneuvers to reduce venous pooling in legs will attenuate the increase in blood pressure
during orthostatic challenge in these subjects. The concepts to be studied challenge the prevailing
“conventional wisdom” regarding how blood pressure is regulated during orthostatic stress. If the proposed
aims are achieved, we will gain insight into the mechanisms by which venous distension evokes
sympathoexcitation, how the VDR interacts with the baroreflex, and how this reflex contributes to blood
pressure control during orthostatic stress.

## Key facts

- **NIH application ID:** 10165803
- **Project number:** 5R01HL144781-03
- **Recipient organization:** PENNSYLVANIA STATE UNIV HERSHEY MED CTR
- **Principal Investigator:** JIAN CUI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $533,395
- **Award type:** 5
- **Project period:** 2019-07-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10165803

## Citation

> US National Institutes of Health, RePORTER application 10165803, The Human Cardiovascular Control: The Role of Limb Veins (5R01HL144781-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10165803. Licensed CC0.

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