RecruitingPHASE4INTERVENTIONAL

Sympathetic Neurovascular Transduction: Role of Adrenergic Receptors and Sex Differences

This research aims to understand how blood pressure control differs between healthy men and women. We want to see if the body's stress response system – often called 'fight or flight' – communicates with blood vessels in different ways depending on your sex. We're also investigating whether specific tiny 'receivers' on blood vessel walls, which react to these signals, work differently in men and women. This involves a single, short visit where we'll take blood and give small amounts of common blood pressure medications to your arm to see how your blood vessels react. We'll also measure nerve activity and use ultrasound to check blood flow.

At a glance

Status

Recruiting

Phase

PHASE4

Sponsor

University of Alberta

Enrolment target

Start

31 Oct 2023

Estimated completion

01 Dec 2027

Vasoconstriction Vasodilation

What is this study about?

Your blood pressure is partly controlled by your 'fight or flight' nervous system. This system can make your blood vessels bigger or smaller, which then changes your blood pressure. We call this communication between your nervous system and your blood vessels 'sympathetic neurovascular transduction' – it's basically how your blood vessels react to those 'fight or flight' signals.

It's already known that men and women control their blood pressure in different ways. For example, women often have lower overall blood pressure and a less intense 'fight or flight' response compared to men. Women's blood vessels also seem to narrow less when they're under stress. We think this might be due to differences in tiny 'receivers' inside the blood vessel walls. These receivers, called alpha and beta-adrenergic receptors, react to signals from your nervous system in opposite ways: alpha receptors make blood vessels narrower, while beta receptors can make them wider.

This study will help us understand more about how these differences work between men and women, especially how these 'receivers' might be more sensitive in women. It could also show if female hormones like oestrogen play a role. Ultimately, learning more about these differences could help doctors better understand and treat heart and blood vessel conditions in the future.

Key takeaways

We're studying how men and women control blood pressure differently.
This involves looking at your 'fight or flight' system and blood vessel responses.
You'll have one visit lasting about 3 hours.
Small doses of medications will be given to your arm, with temporary, localised effects.
The findings could help improve future treatments for heart conditions.
Your general health and pre-study preparation are important for eligibility.

Who may be eligible?

This study is looking for healthy men and women between the ages of 18 and 40.

For women, you must still be having periods (pre-menopausal) and not be pregnant, breastfeeding, or have given birth in the last year.

We cannot include you if you have any diagnosed heart, lung, nervous system, or metabolic health conditions, or if you have any bleeding or clotting disorders. You also can't take part if you're currently taking strong blood thinners, certain MAO inhibitor or tricyclic antidepressant medications, or have a significant smoking history in the last six months. We also can't include those with a BMI classified as obese or any known allergies to components of our study medications. Please let us know if you have used a beta-agonist inhaler (like Ventolin) in the last 24 hours.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 40 years old?
Are you generally healthy, without heart, lung, nervous system, or metabolic conditions?
If you're female, are you having regular periods, not pregnant or breastfeeding, and gave birth over a year ago?
Have you avoided caffeine, alcohol, strenuous exercise, and non-regular medications for 12 hours before a potential visit?
Do you have any bleeding issues or take strong blood thinners?
Do you have any known allergies to common medications like those for blood pressure control?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll come for one study visit that lasts about three hours. During this visit, we will:

* Take a small blood sample to check your natural hormone levels and 'fight or flight' chemicals. * Give you very small amounts of common blood pressure regulating medications through a tiny tube in an arm artery. Don't worry, the effects of these medications are designed to be temporary and only affect your forearm. * Gently insert two very fine needles (like acupuncture needles) into your leg to directly measure your 'fight or flight' nerve activity. This helps us see how active your sympathetic nervous system is. * Regularly check your blood pressure and heart rate. We'll also use a special ultrasound machine to measure the blood flow in your forearm.

Potential risks and benefits

Taking part in this study won't directly improve your personal health, but the information we gather could help us better understand how blood pressure works and improve treatments for heart conditions in the future. There are some minor risks, like slight discomfort or bruising from blood draws and needle insertions. The medications used are in very small, localised doses, designed for short-term effects. You are free to stop your participation at any time, for any reason, without it affecting your medical care.

Locations (1)

University of Alberta
Verified postcode
Edmonton, Canada· Recruiting

Common questions

What is the 'fight or flight' response?

It's your body's natural reaction to stress, making your heart beat faster and blood vessels change size to prepare you for action.

Will the medications affect my whole body?

No, the medications are given in very tiny doses directly into your arm and their effects are designed to be temporary and only affect that arm.

Are the needles painful?

The needles used to measure nerve activity are very fine, similar to acupuncture needles, and are inserted with great care. You might feel a slight prick initially.

How long does the study last?

You will only need to attend one study visit, which will last approximately three hours.

Do I need to do anything special before the visit?

Yes, for at least 12 hours before your visit, you'll need to avoid caffeine, alcohol, strenuous exercise, and any medications you don't take regularly.

How to find out more

Emily Vanden Berg, MSc

ervanden@ualberta.ca (780)-492-5553 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.