Hypothalamic Neurons Regulating Body Temperature

Boulant, Jack A.

doi:10.1002/cphy.cp040106

Cited by 85 publications

(83 citation statements)

References 76 publications

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“…central nervous system and viscera) as well as in more superficial (e.g. skin and muscle) tissues (25,26,122,144,211,217,218,267).…”

Section: Autonomic Temperature Regulationmentioning

confidence: 99%

“…nucleus of the tractus solitarious, parabrachial nucleus) and the hypothalamus could actively contribute to produce neural maps of general physiological states (amongst which temperature sensations), which could be then further processed in second order higher areas (amongst which the insular cortex) and enriched in the context of interactions with other sensory-related cortical areas (amongst which the somatosensory cortex), in order to provide us with our remarkable ability of experiencing a large variety of sensations and emotional states (72,73). The fact that detailed animal models (mice) have provided evidence on the importance of brain stem regions such as the nucleus of the tractus solitarious, as well as on the role of hypothalamus, in regulating and maintaining body temperature in mammals (amongst which humans) (26,218,224), could support this intriguing hypothesis and could further strengthen the proposed neuroanatomical and neurophysiological link between thermosensory function and maintenance of thermal homeostasis. Overall, what emerges from the evidence presented so far is that the central mechanisms of temperature sensations are the result of a complex array and interactions between different neural structures.…”

Section: Cortical Integrationmentioning

confidence: 99%

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Neurophysiology of Skin Thermal Sensations

Filingeri

2016

Comprehensive Physiology

106

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Undoubtedly, adjusting our thermoregulatory behavior represents the most effective mechanism to maintain thermal homeostasis and ensure survival in the diverse thermal environments that we face on this planet. Remarkably, our thermal behavior is entirely dependent on the ability to detect variations in our internal (i.e. body) and external environment, via sensing changes in skin temperature and wetness. In the past 30 years, we have seen a significant expansion of our understanding of the molecular, neuroanatomical and neurophysiological mechanisms that allow humans to sense temperature and humidity. The discovery of temperature-activated ion channels which gate the generation of action potentials in thermosensitive neurons, along with the characterization of the spino-thalamo-cortical thermosensory pathway, and the development of neural models for the perception of skin wetness, are only some of the recent advances which have provided incredible insights on how biophysical changes in skin temperature and wetness are transduced into those neural signals which constitute the physiological substrate of skin thermal and wetness sensations. Understanding how afferent thermal inputs are integrated and how these contribute to behavioral and autonomic thermoregulatory responses under normal brain function is critical to determine how these mechanisms are disrupted in those neurological conditions which see the concurrent presence of afferent thermosensory abnormalities and efferent thermoregulatory dysfunctions. Furthermore, advancing the knowledge on skin thermal and wetness sensations is crucial to support the development of neuro-prosthetics. In light of the above, this review will focus on the peripheral and central neurophysiological mechanisms underpinning skin thermal and wetness sensations in humans.

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“…central nervous system and viscera) as well as in more superficial (e.g. skin and muscle) tissues (25,26,122,144,211,217,218,267).…”

Section: Autonomic Temperature Regulationmentioning

confidence: 99%

Section: Cortical Integrationmentioning

confidence: 99%

Neurophysiology of Skin Thermal Sensations

Filingeri

2016

Comprehensive Physiology

106

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“…Classic studies of central thermoreception focused on the medial preoptic (MPO)/anterior hypothalamic region (10,11). Early ablation studies identified the anterior hypothalamus as important for maintenance of body temperature, and local warming or cooling of the preoptic area elicited appropriate heat loss or heat gain responses.…”

Section: Regulation Of Thermal Homeostasismentioning

confidence: 99%

Integration of thermal and osmotic regulation of water homeostasis: the role of TRPV channels

Sladek

Johnson

2013

American Journal of Physiology-Regulatory, Integrative and Comp

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Sladek CD, Johnson AK. Integration of thermal and osmotic regulation of water homeostasis: the role of TRPV channels. Am J Physiol Regul Integr Comp Physiol 305: R669 -R678, 2013. First published July 24, 2013 doi:10.1152/ajpregu.00270.2013.-Maintenance of body water homeostasis is critical for preventing hyperthermia, because evaporative cooling is the most efficient means of dissipating excess body heat. Water homeostasis is achieved by regulation of water intake and water loss by the kidneys. The former is achieved by sensations of thirst that motivate water acquisition, whereas the latter is regulated by the antidiuretic action of vasopressin. Vasopressin secretion and thirst are stimulated by increases in the osmolality of the extracellular fluid as well as decreases in blood pressure and/or blood volume, signals that are precipitated by water depletion associated with the excess evaporative water loss required to prevent hyperthermia. In addition, they are stimulated by increases in body temperature. The sites and molecular mechanisms involved in integrating thermal and osmotic regulation of thirst and vasopressin secretion are reviewed here with a focus on the role of the thermal and mechanosensitive transient receptor potential-vanilloid (TRPV) family of ion channels. thirst; TRPV; vasopressin; hypothalamus MAINTENANCE of a constant body temperature by homeotherms is critically dependent on body water homeostasis, because evaporative cooling is the most efficient means that homeotherms have for dissipating excess body heat. Even at rest, heat is generated as a by-product of basal cellular metabolism and the ongoing muscle activity of the heart beating, respiration, and gastrointestinal motility. For a typical 70-kg man the resting (basal) rate of metabolic heat production is about 80 kcal/h, but intense exercise can increase heat production to 400 -600 kcal/h. Thus the body must have efficient mechanisms for dissipating heat to prevent hyperthermia. In humans, body heat is dissipated by passive transfer of heat from the skin to the air. The heat generated by muscles and internal organs is transferred to the skin by the blood flowing through epidermal capillaries. Thus heat loss can be increased by increasing skin blood flow and by increasing the movement of air next to the skin by removing clothing and standing near a fan or in a breeze. However, evaporative cooling significantly augments heat loss from the skin, because evaporation of 1 gram of water from the skin dissipates 0.6 kcal. Thus a sweat rate of 1 l/h could theoretically remove 600 kcal/h from the body. Furcovered mammals also rely heavily on evaporative cooling for maintaining body temperature with increased body temperature promoting panting, increased salivation, and saliva spreading in dogs, cats, and rats. However, water loss of the magnitude required in many instances to adequately dissipate excess body heat must be compensated to prevent electrolyte imbalance and preserve blood volume for adequate cardiovascular function. Thus mechanis...

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“…Thermosensitive neurons of the preoptic anterior hypothalamus process afferent thermal information (central and peripheral) to integrate and direct autonomic thermoeffector responses (6,63). Areas of the sympathetic nervous system (hypothalamic area and interomediolateral columns of the spinal cord) that are responsible for controlling thermoregulatory function are susceptible to disease-related pathology in individuals with MS (1).…”

Section: Central Regulation Of Body Temperature In Msmentioning

confidence: 99%

Thermoregulation in multiple sclerosis

Davis

Wilson

White

et al. 2010

Journal of Applied Physiology

148

147

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Davis SL, Wilson TE, White AT, Frohman EM. Thermoregulation in multiple sclerosis. J Appl Physiol 109: 1531-1537. First published July 29, 2010 doi:10.1152/japplphysiol.00460.2010.-Multiple sclerosis (MS) is a progressive neurological disorder that disrupts axonal myelin in the central nervous system. Demyelination produces alterations in saltatory conduction, slowed conduction velocity, and a predisposition to conduction block. An estimated 60 -80% of MS patients experience temporary worsening of clinical signs and neurological symptoms with heat exposure. Additionally, MS may produce impaired neural control of autonomic and endocrine functions. This review focuses on five main themes regarding the current understanding of thermoregulatory dysfunction in MS: 1) heat sensitivity; 2) central regulation of body temperature; 3) thermoregulatory effector responses; 4) heat-induced fatigue; and 5) countermeasures to improve or maintain function during thermal stress. Heat sensitivity in MS is related to the detrimental effects of increased temperature on action potential propagation in demyelinated axons, resulting in conduction slowing and/or block, which can be quantitatively characterized using precise measurements of ocular movements. MS lesions can also occur in areas of the brain responsible for the control and regulation of body temperature and thermoregulatory effector responses, resulting in impaired neural control of sudomotor pathways or neural-induced changes in eccrine sweat glands, as evidenced by observations of reduced sweating responses in MS patients. Fatigue during thermal stress is common in MS and results in decreased motor function and increased symptomatology likely due to impairments in central conduction. Although not comprehensive, some evidence exists concerning treatments (cooling, precooling, and pharmacological) for the MS patient to preserve function and decrease symptom worsening during heat stress. demyelination; core temperature; sweating; skin blood flow; fatigue MULTIPLE SCLEROSIS (MS) is a disabling progressive neurological disorder affecting ϳ400,000 individuals in the United States. The pathophysiology of MS results in a disruption or loss of axonal myelin in the central nervous system (CNS), leading to the formation of scar tissue (sclerosis). MS is thought to involve a number of autoimmune injury cascades that appear to be dependent on the interaction of complex epigenetic and environmental factors. Immune responses in individuals with MS are skewed toward a proinflammatory state, resulting in inflammation, demyelination, and ultimately loss of axons and disorganization of normal tissue architecture within the CNS (23). Demyelination is associated with corresponding changes in axonal physiology, including a loss of saltatory properties of electrical conduction, reduction in conduction velocity, and a predisposition to conduction block. These pathophysiological mechanisms underlie the myriad of symptoms (Table 1) in individuals with MS and are contingent on the neuroanatomic l...

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Hypothalamic Neurons Regulating Body Temperature

Cited by 85 publications

References 76 publications

Neurophysiology of Skin Thermal Sensations

Neurophysiology of Skin Thermal Sensations

Integration of thermal and osmotic regulation of water homeostasis: the role of TRPV channels

Thermoregulation in multiple sclerosis

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