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Sympathetically mediated increases in cardiac output, not restraint of peripheral vasodilation, contribute to blood pressure maintenance during hyperinsulinemia
- Source :
- Am J Physiol Heart Circ Physiol
- Publication Year :
- 2020
- Publisher :
- American Physiological Society, 2020.
-
Abstract
- Vasodilatory effects of insulin support the delivery of insulin and glucose to skeletal muscle. Concurrently, insulin exerts central effects that increase sympathetic nervous system activity (SNA), which is required for the acute maintenance of blood pressure (BP). Indeed, in a cohort of young healthy adults, herein we show that intravenous infusion of insulin increases muscle SNA while BP is maintained. We next tested the hypothesis that sympathoexcitation evoked by hyperinsulinemia restrains insulin-stimulated peripheral vasodilation and contributes to sustaining BP. To address this, a separate cohort of participants were subjected to 5-s pulses of neck suction (NS) to simulate carotid hypertension and elicit a reflex-mediated reduction in SNA. NS was conducted before and 60 min following intravenous infusion of insulin. Insulin infusion caused an increase in leg vascular conductance and cardiac output (CO; P < 0.050), with maintenance of BP (P = 0.540). As expected, following NS, decreases in BP were greater in the presence of hyperinsulinemia compared with control (P = 0.045). However, the effect of NS on leg vascular conductance did not differ between insulin and control conditions (P = 0.898). Instead, the greater decreases in BP following NS in the setting of insulin infusion paralleled with greater decreases in CO (P = 0.009). These findings support the idea that during hyperinsulinemia, SNA-mediated increase in CO, rather than restraint of leg vascular conductance, is the principal contributor to the maintenance of BP. Demonstration in isolated arteries that insulin suppresses α-adrenergic vasoconstriction suggests that the observed lack of restraint of leg vascular conductance may be attributed to sympatholytic actions of insulin. NEW & NOTEWORTHY We examined the role of sympathetic activation in restraining vasodilatory responses to hyperinsulinemia and sustaining blood pressure in healthy adults. Data are reported from two separate experimental protocols in humans and one experimental protocol in isolated arteries from mice. Contrary to our hypothesis, the present findings support the idea that during hyperinsulinemia, a sympathetically mediated increase in cardiac output, rather than restraint of peripheral vasodilation, is the principal contributor to the maintenance of systemic blood pressure.
- Subjects :
- Adult
Male
medicine.medical_specialty
Cardiac output
Sympathetic nervous system
Sympathetic Nervous System
Physiology
medicine.medical_treatment
Blood Pressure
Vasodilation
Mice
Adrenergic Agents
Hyperinsulinism
Physiology (medical)
Internal medicine
medicine
Hyperinsulinemia
Animals
Humans
Insulin
Cardiac Output
Leg
business.industry
Arteries
medicine.disease
Mice, Inbred C57BL
Autonomic nervous system
Blood pressure
medicine.anatomical_structure
Endocrinology
Regional Blood Flow
Female
medicine.symptom
Cardiology and Cardiovascular Medicine
business
Vasoconstriction
Research Article
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Am J Physiol Heart Circ Physiol
- Accession number :
- edsair.doi.dedup.....4bb1a0b49a8530ba18c5455b266f5abc