Assessing static and dynamic sympathetic transduction using microneurography

Abstract

The relationship between sympathetic nerve activity and the vasculature has been of great interest due to its potential role in various cardiovascular-related disease. This relationship, termed "sympathetic transduction", has been quantified using several different laboratory and analytical techniques. The most common method is to assess the association between relative changes in muscle sympathetic nerve activity, measured via microneurography, and physiological outcomes (e.g., blood pressure, total peripheral resistance, and blood flow etc.) in response to a sympathetic stressor (e.g. exercise, cold stress, orthostatic stress). This approach, however, comes with its own caveats. For instance, elevations in blood pressure and heart rate during a sympathetic stressor can have an independent impact on muscle sympathetic nerve activity. Another assessment of sympathetic transduction was developed by Wallin and Nerhed in 1982, where alterations in blood pressure and heart rate were assessed immediately following bursts of muscle sympathetic nerve activity at rest. This approach has since been characterized and further innovated by others, including the breakdown of consecutive burst sequences (e.g., singlet, doublet, triplet, and quadruplet), and burst height (quartile analysis) on specific vascular outcomes (e.g., blood pressure, blood flow, vascular resistance). The purpose of this review is to provide an overview of the literature that has assessed sympathetic transduction using microneurography and various sympathetic stressors (static sympathetic transduction) and using the same or similar approach established by Wallin and Nerhed at rest (dynamic neurovascular transduction). Herein, we discuss the overlapping literature between these two methodologies and highlight the key physiological questions that remain.

The sympathetic nervous system in healthy and hypertensive pregnancies: physiology or pathology?

“…Neurovascular transduction represents the functional effect of a given amount of sympathetic activity on diameter, stiffness and/or resistance within peripheral vessels (Steinback et al, 2019;Tymko et al, 2021).…”

“…Neurovascular transduction represents the functional effect of a given amount of sympathetic activity on diameter, stiffness and/or resistance within peripheral vessels (Steinback et al., 2019 ; Tymko et al., 2021 ). Neurovascular transduction can therefore be represented as peripheral vascular resistance, heart rate and blood pressure responses.…”

“…These neurons release sympathetic neurotransmitters (i.e., noradrenaline and neuropeptide Y (NPY)) that bind to and activate adrenergic receptors on vascular smooth muscle cells. This cascade of events helps to regulate smooth muscle tone and blood pressure through the actions and interactions of neurotransmitters and their receptors (Tymko et al., 2021 ).…”