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K channel impairment determines sex and age differences in epinephrine‐mediated outcomes after brain injury
Author(s) -
Armstead William M.,
Riley John,
Vavilala Monica S.
Publication year - 2017
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.24063
Subject(s) - traumatic brain injury , medicine , endocrinology , autoregulation , cerebral autoregulation , cerebral perfusion pressure , anesthesia , cerebral blood flow , blood pressure , psychiatry
Traumatic brain injury (TBI) is the leading cause of injury‐related death in children, with boys and children under 4 years having particularly poor outcomes. Activation of ATP‐ and calcium‐sensitive (K ATP and K Ca ) channels produces cerebrovasodilation and contributes to autoregulation, both of which are impaired after TBI, contributing to poor outcomes. Upregulation of the c‐Jun‐terminal kinase (JNK) isoform of mitogen‐activated protein kinase produces K channel function impairment after CNS injury. Vasoactive agents can be used to normalize cerebral perfusion pressure. Epinephrine (EPI) prevents impairment of cerebral autoregulation and hippocampal neuronal cell necrosis after TBI in female and male newborn and female juvenile but not male juvenile pigs via differential modulation of JNK. The present study used anesthetized pigs equipped with a closed cranial window to address the hypothesis that differential K channel impairment contributes to age and sex differences in EPI‐mediated outcomes after brain injury. Results show that pial artery dilation in response to the K ATP and K Ca channel agonists cromakalim and NS 1619 was impaired after TBI and that such impairment was prevented by EPI in female and male newborn and female juvenile but not male juvenile pigs. Using vasodilation as an index of function, these data indicate that EPI protects cerebral autoregulation and limits histopathology after TBI through protection of K channel function via blockade of JNK in an age‐ and sex‐dependent manner. © 2017 Wiley Periodicals, Inc.