Stress-induced changes in cellular responses in hypothalamic structures to administration of an antigen (lipopolysaccharide) (in terms of c-Fos protein expression)

Abstract

Stress is known to affect the intensity of the immune response. The involvement of central regulatory structures in mediating these changes was addressed by analyzing the extent of activation of neurons in the hypothalamus (in terms of the number of c-Fos-positive cells) in rats 2 h after i.v. administration of lipopolysaccharide alone and on the background of electrical pain stimulation. Studies were performed using 52 male Wistar rats weighing 200-250 g. c-Fos protein expression was studied by immunohistochemical analysis. Increases in the quantity of c-Fos-positive cells 2 h after administration of lipopolysaccharide were seen in the following hypothalamic structures: AHN, PVH, LHA, VMH, DMH, and PH. After electrical pain stimulation, the number of c-Fos-positive cells increased in these same hypothalamic structures (AHN, PVH, LHA, VMH, DMH, and PH). The combination of electrical pain stimulation and lipopolysaccharide administration led to a decrease in the extent of activation in hypothalamic structures AHN, PVH, LHA, and VMH as compared with the characteristic reaction to lipopolysaccharide without electrical pain stimulation. Electrical pain stimulation suppressed the intensity of the immune response induced by lipopolysaccharide (as assessed by local hemolysis and counts of the numbers of spleen antibody-forming cells). Thus, changes in the extent of activation of hypothalamic structures (AHN, PVH, LHA, VMH) correlated with the development of stress-induced immunosuppression, i.e., morphofunctional mapping of the extent of activation of hypothalamic structures allowed identification of which changes in hypothalamic cell activity occurred with stress-induced changes in immune system responses to antigen administration.

Differential Roles of Cyclooxygenase-2-Related Signaling in Regulating Hypothalamic Neuronal Activity under Various Acute Stresses

“…Interestingly, in the present study, infectious and restraint stresses increased c-Fos expression levels in the VMH, while hypoglycemic stress increased those in the LHA, which are consistent with previous researches reported separately [1, 2, 10, 22]. Bilateral electrolytic lesions of the VMH or LHA were reported to inhibit corticosteroid feedback or extinguish the role of serotonin (5-HT) on activity in the HPA axis [25].…”

Habenular α5 nicotinic receptor subunit signalling controls nicotine intake

“…Wildtype and α5 knockout mice displayed similar Fos immunoreactivity in the ventromedial hypothalamus (Supplementary Fig. 12), a region in which Fos induction is highly stress responsive44, suggesting that altered stress responses in knockout mice did not account for this effect. Nicotine-induced increases in Fos immunoreactivity in the VTA, which controls the reinforcing effects of nicotine, were similar in wildtype and α5 knockout mice (Supplementary Fig.…”

Maternal profiling of corticotropin-releasing factor receptor 2 deficient mice in association with restraint stress

“…Increases in Fos-IR have been shown in this region following various stressors both outside of the postpartum period (Cullinan, Herman et al 1995; Gavrilov, Perekrest et al 2008) and during lactation (Gammie and Stevenson 2006), suggesting its involvement in the general regulation of stress. cPAG is also implicated in the regulation of maternal aggression (Lonstein and Gammie 2002; Gammie 2005; Hasen and Gammie 2005; Hasen and Gammie 2006), suggesting it may be a critical node in the negative regulation of maternal defense behavior modulated by stressors.…”

“…Increases in Fos-IR have been observed in PVN following both restraint stress (Gammie and Stevenson 2006) and immobilization stress in lactating females (da Costa, Wood et al 1996) and male rats (Cullinan, Herman et al 1995; Yokoyama and Sasaki 1999). In addition, both the PVN and PeF have been associated with cellular changes following stress-induced immunosuppression in rats (Gavrilov, Perekrest et al 2008). Likewise, increases in the regulatory peptide vasopressin are seen in SCN following footshock (Handa, Zoeller et al 2007).…”

“…Some regions, including DRD (Hammack, Richey et al 2001; Hammack, Richey et al 2003; Hammack, Schmid et al 2003), LS (Henry, Vale et al 2006) and PVN have been specifically linked to how an animal responds to a stressor. Many of these regions also exhibit cellular changes in response to stress, including PVN, VMH, DMH, PH and various anterior hypothalamic nuclei (Gavrilov, Perekrest et al 2008). c-Fos changes occur following either restraint or swim stress in LS, PVN, AHA, DMH and cPAG (Cullinan, Herman et al 1995).…”