American journal of physiology. Regulatory, integrative and comparative physiology
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Am. J. Physiol. Regul. Integr. Comp. Physiol. · Jan 2008
Endotoxin downregulates peroxisome proliferator-activated receptor-gamma via the increase in TNF-alpha release.
The nuclear receptor peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is anti-inflammatory in a cell-based system and in animal models of endotoxemia. We have shown that PPAR-gamma gene expression is downregulated in macrophages after lipopolysaccharide (LPS) stimulation. However, it remains unknown whether hepatic PPAR-gamma is altered in sepsis and, if so, whether LPS directly downregulates PPAR-gamma. ⋯ Although LPS decreased PPAR-gamma in KCs, the downregulatory effect of LPS was blocked by the addition of TNF-alpha-neutralizing antibodies. Furthermore, the administration of TNF-alpha-neutralizing antibodies to animals before the onset of sepsis prevented the downregulation of PPAR-gamma in sepsis. We, therefore, conclude that LPS downregulates PPAR-gamma expression during sepsis via an increase in TNF-alpha release.
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Am. J. Physiol. Regul. Integr. Comp. Physiol. · Jan 2008
Modulation of cardiac ischemia-sensitive afferent neuron signaling by preemptive C2 spinal cord stimulation: effect on substance P release from rat spinal cord.
The upper cervical spinal region functions as an intraspinal controller of thoracic spinal reflexes and contributes to neuronal regulation of the ischemic myocardium. Our objective was to determine whether stimulation of the C2 cervical spinal cord (SCS) of rats modified the input signal at the thoracic spinal cord when cardiac ischemia-sensitive (sympathetic) afferents were activated by transient occlusion of the left anterior descending coronary artery (CoAO). Changes in c-Fos expression were used as an index of neuronal activation within the spinal cord and brain stem. ⋯ In contrast, SP release from laminae I and II was inhibited when CoAO was applied during preemptive, sustained SCS. Preemptive SCS likewise reduced c-Fos expression in the T4 spinal cord (laminae I-V) and nucleus tractus solitarius but increased expression in the intermediolateral cell column of T4 compared with CoAO alone. These results suggest that preemptive SCS from the high cervical region modulates sensory afferent signaling from the ischemic myocardium.
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Am. J. Physiol. Regul. Integr. Comp. Physiol. · Jan 2008
Comparative StudyEndometriosis as a neurovascular condition: estrous variations in innervation, vascularization, and growth factor content of ectopic endometrial cysts in the rat.
Endometriosis is a poorly understood, estradiol-dependent condition associated with severe pelvic pains and defined by vascularized endometrial growths outside the uterus. Endometriosis is produced in cycling rats by autotransplanting pieces of uterus onto abdominal arteries where they develop into cysts. The surgery induces vaginal and abdominal muscle hyperalgesia, whose severity is greatest in proestrus and nearly absent in estrus. ⋯ In contrast with the cysts, no changes occurred in the uterine horn between proestrus and estrus. Together, these results suggest that coordinated proestrous-to-estrous changes in innervation and vascularization of the cysts contribute to similar changes in hyperalgesic severity. The findings also encourage consideration of endometriosis as a neurovascular condition.