Sex differences in how sympathetic nerves and adrenergic receptors change blood vessel tone

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This interventional, single-visit protocol enrolls healthy adults to compare neurovascular transduction between sexes by combining direct sympathetic nerve recordings with localized intra-arterial drug infusions. Participants provide a blood sample for sex hormones and sympathetic transmitters, undergo microneurography using very small needles to record sympathetic nerve activity, and receive short-acting, low-dose vasoactive drugs delivered to the forearm to probe α- and β-adrenergic receptor function. Vascular responses to norepinephrine, phenylephrine, isoproterenol, and receptor blockade agents (propranolol, phentolamine) are measured to determine how receptor activity differs between males and females. The visit lasts about three hours and the drug effects are localized and short-lived.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Between ages 18-40 years
* No diagnosed medical history of cardiovascular, respiratory, nervous system, or metabolic disease.
* Females must be pre-menopausal.
* Prior to study visit: abstained from caffeine, alcohol, strenuous exercise, and medication not taken regularly for at least 12 hours.

Exclusion Criteria:

* Current diagnosis of cardiovascular, respiratory, nervous system, or metabolic disease that may impact blood pressure regulation. This will be assessed on a case-by-case basis by the study physician.
* Participants with bleeding or clotting disorders, or those currently taking blood thinners.
* Participants currently taking beta-agonist inhalers i.e. Ventolin (at least not in the last 24 hours).
* Females who are pregnant, confirmed by a pregnancy test.
* Females who have are less than 1 year postpartum or are breastfeeding.
* Females who are post-menopausal.
* Participants that are classified as obese (body mass index \> 30 kg ⋅ m2).
* Have a history of smoking regularly in the last 6 months (but nicotine substitutes (i.e. patch, gum) are not an exclusion criteria).
* Those with a known allergy to sulfites, or other components of the supplied solution of study drugs.
* Participants taking medications that are contraindicated with any of the study drugs, such as monoamine oxidase (MAO) inhibitors or tricyclic antidepressants.
* Participants who have not adhered to the pre-testing guidelines related to diet, alcohol or exercise will not be excluded, but will be rescheduled for a different day. This is to reduce experimental variability.

Where it's running

• University of Alberta
  Edmonton, Alberta, Canada Recruiting

Study contacts

• Principal investigator: Sean van Diepen, MD, MSc — University of Alberta
• Study coordinator: Emily Vanden Berg, MSc
• Email: ervanden@ualberta.ca
• Phone: (780)-492-5553

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.