View clinical trials related to Vasoconstriction.
Filter by:The main purpose of this interventional study is to examine differences in resting blood pressure control between healthy males and females. The main questions it aims to answer are: 1. Are there sex differences in the communication between the sympathetic nervous system (also known as the "fight or flight" response) and peripheral blood vessels (which influence systemic blood pressure)? 2. What is the role of specific vascular receptors that respond to sympathetic signals, and is it different between males and females? Participants will complete one study visit of approximately 3 hours where they will: - Have a blood sample taken to measure circulating sex hormone and sympathetic transmitters. - Receive very small doses of medications commonly used to adjust blood pressure through an artery in their arm. The effects of these medications will be short-acting and localized to the forearm. - Have their sympathetic nervous activity directly measured through two very small needles (similar to acupuncture needles) in the side of their leg. - Have their blood pressure and heart rate recorded, and forearm blood flow measured using ultrasound.
In septic shock there is growing evidence of a state of hemodynamic "disconnection" with seemingly adequate macrocirculatory values despite actual microcirculation failing to meet cellular demand. Norepinephrine (NE) is recommended as first choice vasoactive agent for the treatment of septic shock. However, the dynamic effects of NE on macro- and microcirculation and perfusion parameters has not been described in detail in the context of septic shock, precluding rational individualized titration of NE and fluids, as recommended recently. In the present prospective observational multicenter study in adult septic shock patients, we intend to explore the effects of NE on preload dependency and tissue perfusion by evaluating the correlation and potential discrepancies between macro- and microcirculation both during titration of NE and after fluid resuscitation. The conclusions drawn from our study will contribute to the physiological knowledge necessary for establishing individualized evidence-based bedside management of hemodynamics in the setting of septic shock.
Patients with sleep apnea are at increased risk of developing cardiovascular disease - with women at potentially greater risk than men. Contributing mechanisms are not well understood, but may be related to how women respond to low oxygen and, given over 70% of patients with sleep apnea are obese, the impact of obesity. This project seeks to increase our understanding of mechanisms that may contribute to sex differences in the cardiovascular response to low oxygen with the hope that this knowledge will improve the efficacy of current therapies and support the discovery of novel therapeutics.
Cardiovascular disease (CVD) afflicts nearly one-third of the adult population with all races and ethnicities represented in CVD prevalence. Unfortunately, a disparity exists such that the black population (BL) is disproportionately affected compared to other groups, including the white population (WH). While the underlying cause of this disparity is multifactorial, vascular dysfunction (i.e., impaired vasodilation and/or augmented vasoconstriction) is a key contributor. As has been previously observed, BL exhibit a heightened vasoconstrictor response to both pharmacological (e.g., alpha-adrenergic receptor agonists) and environmental (e.g., cold pressor test) stimuli compared to their WH counterparts. Additionally, reactive oxygen species (ROS) and the subsequent reduction in nitric oxide (NO) bioavailability may partially mediate this response. Our laboratory has recently observed (UTA IRB 2016-0268) that the small blood vessels in the skin (cutaneous microvasculature) in BL, but otherwise healthy individuals, produce an impaired blood flow response to local heating when compared to age-, body mass index (BMI)-, and gender-matched WH. However, pre-treatment of the cutaneous microvasculature with various antioxidants abolishes this skin blood flow difference. These antioxidant drugs inhibit possible sources of ROS, which, as mentioned, maybe mediating the heightened vasoconstrictor response in BL. However, this has not been investigated in this population and thus remains unknown. Therefore, the purpose of this study proposal is to test the following hypotheses: 1) BL will have a greater reduction in cutaneous blood flow in response to local administration of Norepinephrine (alpha1-adrenergic and alpha 2-adrenergic receptor agonist) relative to WH. 2) This greater reduction in the BL population will be related to elevated oxidative stress and subsequent reduction in bioavailability of the potent vasodilator Nitric oxide.
The goal of the study is to examine the possible mechanisms of impaired cutaneous microvascular function through local heating along with administration of vasoconstrictors.