Functional role of peripheral vasoconstriction: not only thermoregulation but much more

Abstract

Peripheral vasoconstriction is a centrally mediated physiological effect known to play an important role in regulating body temperature by adjusting heat exchange with the external environment. However, peripheral vasoconstriction as a component of sympathetic activation also occurs following exposure to various salient stimuli and during motivated behavior at stable environmental temperatures. This review aims to consider available evidence suggesting a significant contribution of this peripheral effect to physiological increases in both brain temperature and entry of oxygen and glucose into the brain's extracellular space. While these effects are triggered by neuronal activation, constriction of blood vessels in the skin and most internal organs results in redistribution of blood from the peripheral to central domains, thus dilating cerebral vessels, increasing global cerebral blood flow, and enhancing the intra-brain entry of oxygen and glucose from arterial blood. This powerful influence appears to determine the long duration of physiological increases in both brain temperature and brain levels of glucose and oxygen and their basic similarity across different brain structures. This work underscores the tight interrelationship between the brain and periphery and a significant contribution of cardiovascular effects in providing the enhanced inflow of oxygen and glucose into brain tissue to prevent metabolic deficit during functional neural activation.

Hypothalamic Neuromodulation of Hypothermia in Domestic Animals

“…Consequently, a thermogenic afferent pathway involving the dorsomedial hypothalamus (DMH) and premotor neurons in the raphe pallidus (RPa) stimulates the autonomic, somatic, motor, endocrine, and behavioral changes [43,45]. These include cutaneous vasoconstriction to diminish heat losses and thermogenic mechanisms such as the use of brown adipose tissue [46,47]. On the one hand, sympathetic preganglionic neurons modulate BAT thermogenesis, while alpha and gamma motor neurons modulate shivering, and sympathetic premotor cutaneous vasoconstrictor neurons in the raphe cause vasoconstriction [48][49][50].…”

Noninvasive characterization of peripheral sympathetic activation across sensory stimuli using a peripheral arterial stiffness index

“…The sympathetic nervous system (SNS) responds to environmental cues and innervates peripheral tissues in a highly selective manner, maintaining homeostasis precisely and cost-effectively Kregel et al (1992) ; Boron and Boulpaep (2017) ; Greaney and Kenney (2017) . For example, mild arousal induces a reduction in cutaneous blood flow to maintain cerebral oxygenation and sensory focus, and intense emotional stress elicits an increase in skeletal muscle blood flow to prepare for a defense reaction, the latter commonly known as the “fight-or-flight” response Kiyatkin (2021) . Whereas the valence and intensity of the stimulus determine differential sympathetic outflow to the target tissue, tissue-specific behaviors like vasomotion, sudomotion, cardiac activation, and thermogenesis also reflect the dynamics of their respective sympathetic innervation Morrison (2001) ; Mano et al (2006) ; Hu et al (2020) ; Kandel et al (2021) .…”