---
title: "Reflex Responses to Intermittent Hypoxia in Humans: Mechanisms and Consequences"
nct_id: NCT05146089
overall_status: COMPLETED
phase: EARLY_PHASE1
sponsor: University of Missouri-Columbia
study_type: INTERVENTIONAL
primary_condition: Sleep Apnea
countries: United States
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT05146089.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT05146089"
ct_last_update_post_date: 2021-12-06
last_seen_at: "2026-05-12T06:50:36.285Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Reflex Responses to Intermittent Hypoxia in Humans: Mechanisms and Consequences

**NCT ID:** [NCT05146089](https://clinicaltrials.gov/study/NCT05146089)

## Key Facts

- **Status:** COMPLETED
- **Phase:** EARLY_PHASE1
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 54
- **Lead Sponsor:** University of Missouri-Columbia
- **Collaborators:** National Heart, Lung, and Blood Institute (NHLBI), Mayo Clinic
- **Conditions:** Sleep Apnea, Healthy, Vasoconstriction, Vasodilation
- **Start Date:** 2016-12-20
- **Completion Date:** 2021-04-12
- **CT.gov Last Update:** 2021-12-06

## Brief Summary

The overall goal of this project is to better understand the effect of intermittent hypoxia (IH) on sympathetic neuronal discharge patterns in humans, as well as mechanisms that mediate persistent sympathoexcitation with IH.

## Detailed Description

Sleep apnea is the most common form of sleep disordered breathing and patients with sleep apnea exhibit persistent activation of the sympathetic nervous system. Sympathoexcitation is also the final common pathway for a host of complications in conditions like obesity, hypertension, sleep apnea, and heart failure and plays a significant role in predicting negative clinical outcomes and deteriorating cardiovascular health. However, the mechanisms of sympathoexcitation with sleep apnea are poorly understood and thus make effective therapeutic approaches difficult to develop.

Intermittent hypoxia (IH) has been implicated in animal models as the primary stimulus for evoking increases in sympathetic activity with recurrent apneas. Thus, the overall goal of this application is to better understand the effect of IH on sympathetic discharge patterns in humans as well as the mechanisms mediating persistent sympathoexcitation with IH. By better understanding the effect of IH on sympathoexcitation, targeted therapeutic approaches might be devised to mitigate the effects of sympathetic over-activity on the cardiovascular system in conditions such as sleep apnea.

## Eligibility

- **Minimum age:** 18 Years
- **Maximum age:** 45 Years
- **Sex:** ALL
- **Healthy Volunteers:** Yes

```
Inclusion Criteria:

* healthy adult men and women;
* 18-45 years of age;
* BMI \<30 kg/m2;
* non-pregnant/non-breastfeeding;
* non-smokers.

Exclusion Criteria:

Subjects will be excluded if they are:

* taking any medications known to affect the cardiovascular or autonomic nervous system (e.g. alpha-blockers, beta-blockers, etc);
* Apnea Hypopnea Index \>10 events/hr

Self-reported history of:

* hepatic, renal, pulmonary, cardiovascular, or neurological disease;
* stroke or neurovascular disease;
* bleeding/clotting disorders;
* sleep apnea or other sleep disorders;
* diabetes;
* smoking;
* history of alcoholism or substance abuse;
* hypertension.
```

## Arms

- **Hypoxia Exposure** (EXPERIMENTAL) — Men and women will be exposed to acute intermittent hypoxic episodes.

## Interventions

- **Hypoxic exposure** (OTHER) — 30 minutes of intermittent hypoxia achieved using breaths of low oxygen air (5% oxygen) followed by room air through a mask.
- **modified Oxford test** (OTHER) — An intravenous bolus of sodium nitroprusside (100 μg) will be given to decrease blood pressure, followed 1 minute later by a bolus of phenylephrine (150 μg) to increase blood pressure, occurring before and after intermittent hypoxia exposure.
- **Oral Bosentan 62.5 mg** (DRUG) — Prior to completion of visit 2, male subjects will consume 62.5 mg twice daily for 3 days as well as the morning of the study visit (7 pills) at home and experimental sessions will be performed 3 hours after oral intake of the final dose.
- **Hypoxic ventilatory response test** (OTHER) — Hypoxia will be achieved using breaths of low oxygen air (5% oxygen) followed by room air through a mask. This will be repeated 4-5 times per test, occurring before and after intermittent hypoxia exposure.

## Primary Outcomes

- **Muscle sympathetic nerve activity (MSNA)** _(time frame: Change from baseline after hypoxia exposure)_ — MSNA burst incidence (bursts/100 heart beats)

## Secondary Outcomes

- **Arterial blood pressure** _(time frame: Change from baseline after hypoxia exposure)_

## Locations (2)

- University of Missouri-Columbia, Columbia, Missouri, United States
- Mayo Clinic, Rochester, Missouri, United States

## Recent Field Changes (last 30 days)

- `armsInterventions.arms` — added _(2026-05-12)_
- `status.overallStatus` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.maxAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `outcomes.secondary` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `sponsor.collaborators` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.university of missouri-columbia|columbia|missouri|united states` — added _(2026-05-12)_
- `locations.mayo clinic|rochester|missouri|united states` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT05146089.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT05146089*  
*This page is a raw mirror with no AI summary, no editorial enrichment, and no Parkinson's-specific filtering.*