c-Fos immunoreactivity in selected brain regions of rats after heat exposure and pyrogen administration

doi:10.1016/j.brainres.2006.08.062

Brain Research

Volume 1120, Issue 1, 20 November 2006, Pages 124-130

https://doi.org/10.1016/j.brainres.2006.08.062 Get rights and content

Abstract

We determined c-Fos immunoreactivity (Fos-IR) in selected hypothalamic nuclei, the organum vasculosum of the laminae terminals (OVLT) and somatosensory cortex of rats after hyperthermia induced by exogenous heat exposure, Gram-negative or Gram-positive pyrogen administration. The magnitude of Fos-IR was similar in thermoregulatory hypothalamic nuclei of rats after heat exposure or lipopolysaccharide (LPS) injection, despite the different origins of the hyperthermias. Heat-induced hyperthermia was associated with increased Fos-IR in the somatosensory cortex. LPS, but not heat exposure or injection of killed Staphylococcus aureus cells activated OVLT neurons. The OVLT may thus not be a port of entry for humoral mediators of Gram-positive bacterial fevers.

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Acknowledgments

Funded by the South African Medical Research Council. I du Plessis was supported by a postdoctoral fellowship from the National Research Foundation, South Africa.

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Cited by (11)

Regional differences of cFos immunoreactive cells in the preoptic areas in hypothalamus associated with heat and cold responses in mice
2018, Neuroscience Letters
Citation Excerpt :
Tb at 38 °C was greater than that at 27 °C (Fig. 1). This result coincides with previous studies that Tb increased during various heat exposures: 34 °C in mice [41] and 32–40 °C in rats [3,11,21,32]. Consistent with previous studies that Tb did not change during cold exposures: 10 °C and 20 °C [12,39–41] in mice and 10 °C in rats [21], 10 °C exposure did not affect Tb (Fig. 1).
cFos expression in the preoptic area (PO), which is thermoregulatory center increased by both heat and cold exposures; however, the regional difference is unknown yet. We aimed to determine if cFos expression in the PO was regionally different between heat and cold exposures. Mice were exposed to 27, 10, or 38 °C for 90 min, and body temperature (T_b) was measured. cFos-immunoreactive (cFos-IR) cells in the PO were counted by separating the PO into the ventral and dorsal parts in the rostral (bregma 0.38 mm), central (−0.10 mm), and caudal (−0.46 mm) planes. T_b at 10 °C remained unchanged; however, it increased at 38 °C. Counts of cFos-IR cells in all areas were greater at 38 °C than at 27 °C. In the dorsal and ventral parts of the central and the dorsal part of caudal PO, counts of cFos-IR cells were greater at 10 °C than at 27 °C. In conclusion, the areas of increased cFos expression in the PO in the heat were different that in the cold in mice.
Sickness behavior is accentuated in rats with metabolic disorders induced by a fructose diet
2015, Journal of Neuroimmunology
Citation Excerpt :
By contrast, Lawrence et al. (2012) observed either fewer Fos-positive cells or no significant activation of said cells in the SON or BNST of obese mice treated with LPS; the PVN exhibited a significant increase in the number of Fos-positive cells, however. Regarding thermoregulation, increased Fos expression was observed in the MPOA of rats treated with fructose, and several studies have described increased Fos expression in both the PVN and the MPOA of rats following LPS stimulation (Elmquist et al., 1996, 1997; du Plessis et al., 2006). In summary, the results of the present study strongly demonstrate that fructose supplementation induces metabolic disorders such as dyslipidemia and the enhanced accumulation of visceral adipose tissue.
This study investigated behavioral responses to an immune challenge among animals with fructose-induced metabolic disorders. Adult male Wistar rats were provided either water or a fructose solution (10%) for 5 weeks. Sickness behaviors were assessed 2 h following the injection of either a lipopolysaccharide (LPS) or vehicle. The rats were subjected to an open field test, a social interaction test, a food intake test and a fever evaluation. Cytokine expression was assessed in both adipose tissue and hypothalamus samples. The neural response was assessed in the forebrain immunohistochemistry for c-Fos. Compared with the control group, the fructose diet induced dyslipidemia and significantly higher plasma total cholesterol, HDL-cholesterol, triglyceride, and glucose levels as well as both epididymal and retroperitoneal adiposity. Furthermore, in response to LPS (1 mg/kg), the rats subjected to a fructose diet exhibited exacerbated sickness behaviors and accentuated febrile responses. LPS induced Fos protein expression in several areas of the brains of the control rats; however, higher numbers of Fos-positive cells were observed in the brains of the rats that were fed a fructose diet. Moreover, larger increases in cytokine expression were observed in both the hypothalamus and the adipose tissue of the obese rats compared with the control rats in response to LPS. In this study, fructose diets played an important role in both the induction of metabolic disorders and the modulation of sickness behaviors in response to an immunological challenge, most likely through the induction of cytokines in the hypothalamus.
Effect of low estrogen on neurons in the preoptic area of hypothalamus of ovariectomized rats
2014, Acta Histochemica
Citation Excerpt :
After warm stimulus by 34 °C, expression of c-Fos protein is observed in the MnPO, LPA (lateral preoptic area), AH (hypothalamic area) and DMH (dorsomedial hypothalamic nucleus) (Harikai et al., 2003). After warm stimulus by 37 °C, a strong expression of c-Fos protein is observed in the MPA, CeA (central amygdaloid nucleus), BLA, LPB and P5 (Plessis et al., 2006). After cold stimulus by 4 °C, a strong expression of c-Fos protein is observed in MPA, LPB (lateral parabrachial nucleus), P5 (peritrigeminal nucleus) and few expressions in BLA (basolateral amygdaloid nuclei) (Bratincsak and Palkovits, 2004).
The purpose of this study was to investigate the difference in neuronal activity in the preoptic area of the hypothalamus (POAH) under low estrogen condition induced by ovariectomy. One hundred and twenty sham-operated (SHAM) and ovariectomized (OVX) rats were placed in different temperatures for 2 h. Twelve rats from each group were stimulated by 4 °C, 10 °C, 25 °C, 33 °C and 38 °C, respectively. c-Fos expression in the POAH was detected by immunohistochemistry. Following exposure to warm and cold stimuli, there were markedly lower c-Fos-positive cell densities in the OVX group compared with the SHAM group in the median preoptic nucleus (MnPO) at 4 °C, 10 °C, 33 °C and 38 °C, in the medial preoptic area (MPA) at 25 °C and 38 °C, in the ventromedial preoptic nucleus (VMPO) at 4 °C, 10 °C and 38 °C and in the ventrolateral preoptic nucleus (VLPO) at 4 °C and 38 °C. Both temperature and surgery had an impact on c-Fos expression by two-way ANOVA method except in the lateral preoptic area (LPO). c-Fos expression differed within different nuclei of the two groups in the same and different temperature stimuli. This indicated that the temperature-sensitive nuclei in the POAH exhibited lower and different activities during temperature stimuli following ovariectomy, which possibly resulted in abnormal thermoregulation and menopausal symptoms.
The relationship between locomotion and heat tolerance in heat exposed rats
2010, Behavioural Brain Research
Low spontaneous locomotor activity (SA) represents a thermoregulatory behaviour that aims at improving heat tolerance. However, high SA is observed during heat exposure. We hypothesized that high SA could be associated to brain dysfunction. Eighty male Sprague–Dawley rats were heat exposed for 90-min under a continuous assessment of SA and abdominal temperature (T_abd) using telemetry. The time course analysis showed two SA peaks. The first one was related to exposure to novel environment, the second to heat. The maximal SA level reached in the second peak served to distribute the rats into three groups (LOW, MED and HIGH). In each SA pattern group, heat tolerance was estimated from T_abd values. At the end of heat exposure, frontal cortex activation was assessed using c-fos, Hsp70 and IκBα mRNA expressions. The LOW rats exhibited the lowest T_abd, a slight increase in c-fos and Hsp70 mRNA expressions and a robust increase in IκBα mRNA expression. The HIGH rats exhibited the highest T_abd and a robust increase in c-fos and Hsp70 mRNA expressions without any change in IκBα mRNA expression. The c-fos and Hsp70 mRNA expressions were positively correlated to the highest SA levels occurring 45 min before sacrifice, suggesting that high SA and frontal cortex activation are related. In conclusion, high SA is associated to decreased heat tolerance and frontal cortex activation. It may represent a marker of inadequate stress reaction.
Hyperalgesia induced by oral stavudine administration to rats does not depend on spinal neuronal cell death, or on spinal or systemic inflammatory cytokine secretion, or metabolic dysregulation
2009, NeuroToxicology
To investigate possible mechanisms of the hyperalgesia induced by the nucleoside reverse transcriptase inhibitor (NRTI) stavudine in rats, we examined neuronal death and inflammatory cytokine secretion in the spinal cord, and cytokine and lactate secretion in the plasma. Stavudine (50 mg kg⁻¹) or placebo was administered orally to Sprague–Dawley rats once daily for three or six weeks. In one group, rats’ responses to a blunt noxious mechanical stimulus applied to their tails were recorded before and at the end of the period of stavudine or placebo administration. Spinal cords excised from these rats after three and six weeks of stavudine or placebo administration were examined for neuronal necrosis and apoptosis. In a second group of rats, plasma and spinal cord samples collected after three and six weeks of placebo or stavudine administration were examined for changes in CINC-1, IL-6, adiponectin (plasma only) and lactate (plasma only) concentration. Daily stavudine administration induced mechanical hyperalgesia within three weeks, which was sustained until week six, but the hyperalgesia was not associated with neuronal apoptosis or necrosis, or elevated IL-6 concentrations in the spinal cord. The spinal cord concentration of CINC-1 increased, but only after six weeks of stavudine administration, when the hyperalgesia had been established for over three weeks. Stavudine administration did not affect the plasma concentration of IL-6, CINC-1, adiponectin or lactate. Thus, neither peripheral nor central inflammatory cytokine secretion, or neuronal death, or metabolic dysregulation contributed to the development of hyperalgesia in our model of stavudine-induced hyperalgesia in rats.
Optogenetic stimulation of prefrontal glutamatergic neurons enhances recognition memory
2016, Journal of Neuroscience

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Short Communicationc-Fos immunoreactivity in selected brain regions of rats after heat exposure and pyrogen administration

Abstract

Section snippets

Acknowledgments

Brain Res.

Brain Res. Bull.

Neuroscience

Trends Neurosci.

Brain Res.

Brain Res. Bull.

Neurosci. Lett.

Brain Res. Mol. Brain Res.

Brain Res.

Thermoregulation

Route of administration differentially affects fevers induced by Gram-negative and Gram-positive pyrogens in rabbits

Exp. Physiol.

Activation of neurons projecting to the paraventricular hypothalamic nucleus by intravenous lipopolysaccharide

J. Comp. Neurol.

Distribution of Fos-like immunoreactivity in the rat brain following intravenous lipopolysaccharide administration

J. Comp. Neurol.

The hypothalamus

Staphylococcal enterotoxin B induces fever, brain c-Fos expression, and serum corticosterone in rats

Am. J. Physiol., Regul. Integr. Comp. Physiol.

Selected contribution: role of IL-6 in LPS-induced nuclear STAT3 translocation in sensory circumventricular organs during fever in rats

J. Appl. Physiol.

Short Communication
c-Fos immunoreactivity in selected brain regions of rats after heat exposure and pyrogen administration