Location of cat brain stem neurons that drive sweating

Shafton, Anthony D; McAllen, Robin M.

doi:10.1152/ajpregu.00040.2013

Cited by 23 publications

(12 citation statements)

References 41 publications

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“…Interestingly, a similarity exists in location of the medullary area showing UTC-correlated activations to the rostral-lateral medullary area previously reported to be activated in response sweat-inducing stimuli (Farrell et al 2013(Farrell et al , 2015. This location is homologous with the sympathetic premotor nuclei (rostral ventrolateral medulla/C1 adrenergic group) in cat (Shafton and McAllen 2013), and our data may reflect airway vagal afferent inputs regulating sympathetic autonomic processes. Alterna-tively, a similar region is activated during BOLD imaging of brain stem responses to inspiratory loading in human participants (Yu et al 2016).…”

Section: Physiological Implicationssupporting

confidence: 82%

Regional brain stem activations during capsaicin inhalation using functional magnetic resonance imaging in humans

Bautista

Leech

Mazzone

et al. 2019

Journal of Neurophysiology

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Coughing is an airway protective behavior elicited by airway irritation. Animal studies show that airway sensory information is relayed via vagal sensory fibers to termination sites within dorsal caudal brain stem and thereafter relayed to more rostral sites. Using functional magnetic resonance imaging (fMRI) in humans, we previously reported that inhalation of the tussigenic stimulus capsaicin evokes a perception of airway irritation (“urge to cough”) accompanied by activations in a widely distributed brain network including the primary sensorimotor, insular, prefrontal, and posterior parietal cortices. Here we refine our imaging approach to provide a directed survey of brain stem areas activated by airway irritation. In 15 healthy participants, inhalation of capsaicin at a maximal dose that elicits a strong urge to cough without behavioral coughing was associated with activation of medullary regions overlapping with the nucleus of the solitary tract, paratrigeminal nucleus, spinal trigeminal nucleus and tract, cardiorespiratory regulatory areas homologous to the ventrolateral medulla in animals, and the midline raphe. Interestingly, the magnitude of activation within two cardiorespiratory regulatory areas was positively correlated ( r2 = 0.47, 0.48) with participants’ subjective ratings of their urge to cough. Capsaicin-related activations were also observed within the pons and midbrain. The current results add to knowledge of the representation and processing of information regarding airway irritation in the human brain, which is pertinent to the pursuit of novel cough therapies. NEW & NOTEWORTHY Functional brain imaging in humans was optimized for the brain stem. We provide the first detailed description of brain stem sites activated in response to airway irritation. The results are consistent with findings in animal studies and extend our foundational knowledge of brain processing of airway irritation in humans.

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Section: Physiological Implicationssupporting

confidence: 82%

Regional brain stem activations during capsaicin inhalation using functional magnetic resonance imaging in humans

Bautista

Leech

Mazzone

et al. 2019

Journal of Neurophysiology

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“…The more rostral part of the RVMM, at the level of the facial nucleus, contains premotor neurons that regulate the sympathetic outflow to the stellate ganglion (82) which contains sympathetic postganglionic neurons innervating sweat glands (2). Consistent with this, glutamate microinjections into this rostral part of the RVMM evokes sweating in the paw of the cat but has no effect on arterial pressure (135). Sweating in the paw of the cat or rat may be analogous to sweating in the human hand, which is typically evoked by psychological stress (100).…”

Section: Premotor Nuclei Driving Stress-evoked Sympathetic Activitymentioning

confidence: 88%

Central mechanisms regulating coordinated cardiovascular and respiratory function during stress and arousal

Dampney

2015

American Journal of Physiology-Regulatory, Integrative and Comp

127

116

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Actual or potentially threatening stimuli in the external environment (i.e., psychological stressors) trigger highly coordinated defensive behavioral responses that are accompanied by appropriate autonomic and respiratory changes. As discussed in this review, several brain regions and pathways have major roles in subserving the cardiovascular and respiratory responses to threatening stimuli, which may vary from relatively mild acute arousing stimuli to more prolonged life-threatening stimuli. One key region is the dorsomedial hypothalamus, which receives inputs from the cortex, amygdala, and other forebrain regions and which is critical for generating autonomic, respiratory, and neuroendocrine responses to psychological stressors. Recent studies suggest that the dorsomedial hypothalamus also receives an input from the dorsolateral column in the midbrain periaqueductal gray, which is another key region involved in the integration of stress-evoked cardiorespiratory responses. In addition, it has recently been shown that neurons in the midbrain colliculi can generate highly synchronized autonomic, respiratory, and somatomotor responses to visual, auditory, and somatosensory inputs. These collicular neurons may be part of a subcortical defense system that also includes the basal ganglia and which is well adapted to responding to threats that require an immediate stereotyped response that does not involve the cortex. The basal ganglia/colliculi system is phylogenetically ancient. In contrast, the defense system that includes the dorsomedial hypothalamus and cortex evolved at a later time, and appears to be better adapted to generating appropriate responses to more sustained threatening stimuli that involve cognitive appraisal. defensive behavior; sympathetic activity; respiratory activity; hypothalamus; midbrain; sympathetic premotor nuclei AN ANIMAL'S SURVIVAL is dependent on being able to respond appropriately to stressors, which can be categorized into two different groups: interoceptive (also-called physical) stressors and exteroceptive (also-called psychological) stressors (44,133). Physical stressors are those that directly threaten homeostasis, such as hypoxia, hemorrhage, or infection, whereas psychological stressors can be defined as actual or perceived threats in the external environment. Psychological stressors can be further subdivided into conditioned stressors (i.e., ones that are normally innocuous but which are perceived as threatening because of previous experiences) or unconditioned stressors (i.e., ones that are intrinsically threatening, such as the sight, sound, or odor of a predator). Physical and psychological stressors activate different populations of neurons in the brain (44,63,102). Similarly, there is evidence that the autonomic responses to conditioned and unconditioned psychological stressors are also mediated by different pathways in the brain (62). In this review, which is based on my 2013 Carl Ludwig Distinguished Lecture to the American Physiological Society, I consider the brain mec...

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“…In answer to our second question-Was any region associated specifically with psychogenic or thermal sweating?-no region showed any such preference. To our final question-Could we identify the human homolog of the rostral medullary cell group that drives sweating in cats (49)?-the answer is yes (discussed below).…”

Section: Discussionmentioning

confidence: 99%