Search

Background: Hypothalamic synthesis and secretion of corticotropin-releasing hormone (CRH), a putative mediator of various behavioral and physiological responses to ethanol (EtOH), is defective in inbred Lewis (LEW) rats in comparison with their genetically related inbred Fischer 344 (F344) and outbred Sprague–Dawley (S–D) strains. We aimed to characterize the effects of continuous EtOH consumption and withdrawal on circadian patterns of body temperature and spontaneous locomotor activity in males and females of these 3 strains. Methods: Adult LEW, F344, and S–D males and randomly cycling females were fed an EtOH-containing liquid diet or the control (pair-fed or lab chow and water) diet for 14 days. Biotelemetric body temperature data for the last 3 days of EtOH diet feeding and the first 3 days of withdrawal were subjected to cosinor analysis of the circadian rhythm parameters of midline-estimating statistic of rhythm (MESOR), amplitude, and acrophase. Mean dark-phase activity during these periods was also computed. Results: In the control diet condition, the MESORs and amplitudes of LEW males were lower than those of F344 males. MESORs of rhythms of LEW females were lower than those of both F344 and S–D females. Ethanol consumption caused hypothermia with reduced MESORs and amplitudes of LEW and F344 males and amplitudes of F344 and S–D females. Upon withdrawal, MESORs of the males increased during each day as the amplitudes decreased, reflective of their initial withdrawal-induced dark-phase hypothermia, which was most pronounced in the LEW males, followed by light-phase hyperthermia. MESORs of females were not affected by withdrawal; their amplitudes were differentially affected. Acrophase of LEW males shifted from dark to light on the first day of withdrawal. All rats responded to EtOH exposure with a reduction of dark-phase spontaneous locomotor activity and an immediate increase upon withdrawal. Conclusions: Body temperature rhythms of the males were generally more affected by EtOH consumption and withdrawal than the females; within each sex, LEW and F344 rats differed significantly. The specific hormonal factors that mediate the differential temperature responses remain to be defined.

Background: Chronic and acute alcohol use exert profound modulatory effects on the immune system which manifest as impaired host defense against infections. An important feature of this response is the interaction between the immune and the central nervous systems. This study investigated the effects of 14 days of alcohol exposure on cytokine-mediated neuroimmune interactions that affect the febrile component of the host-defense response. Methods: Adult male rats were fed a liquid diet containing ethanol (EtOH, 5% w/v) for 14 days. Pair-fed and normal chow- and water-fed rats served as controls. Continuous biotelemetric recordings of body temperature and locomotor activity commencing after 14 days of EtOH feeding were used to determine the effects of chronic EtOH on the circadian pattern of temperature and activity, on the febrile response to intraperitoneal (ip) administration of lipopolysaccharide (LPS) and interleukin (IL)-1, and on fever induced by IL-1 administered intracerebroventricularly. We also examined the effects of EtOH consumption on LPS-induced hypothalamic production of the pyrogenic cytokines IL-1 and tumor necrosis factor- (TNF) and on the blood levels of IL-1, TNF, IL-6, adrenocorticotropin, and corticosterone at 2, 4, and 6 hr after ip LPS. Results: Fourteen days of EtOH consumption blunted the circadian increases in temperature and activity that normally occur in the dark phase of the light/dark cycle without affecting light-phase temperature or activity. EtOH consumption attenuated fever induced by LPS or IL-1 administered ip during the light phase and significantly reduced hypothalamic production of IL-1. LPS-induced increases in hypothalamic TNF and blood cytokines, adrenocorticotropin, and corticosterone were unaffected. Central administration of IL-1 produced a normal febrile response in chronic-EtOH rats. Conclusions: The attenuated LPS- and IL-1–induced febrile responses in EtOH-consuming rats and the corresponding deficit in hypothalamic production of IL-1 suggest that alcohol may impair IL-1– mediated neuroimmune communication.

We previously reported altered responses of thymocytes to mitogen stimulation after fetal alcohol exposure (FAE) in prepubertal male Sprague-Dawley rats. The purpose of this study was to examine the effect of FAE on the developmental pattem of thymocyte subsets. In the first experiment, we found that the proportion of double-labeled CD4 + CD8 + thymocytes is identical in fetal alcohol-exposed (E) and control (C) animals at 34 and 45 days of age. In the second experiment-at 20, 28, 35, and 48 days of age-we examined the proportion of CD4 + and CD8 + thymocytes that express or are devoid of the maturational markers, the α/β configuration of the T-cell receptor (TcR), and the restriction fragment C of the common leukocyte antigen (CD45RC). We found significant age-dependent effects on the numbers of total double-positive CD4-TcR and CD8-TcR or CD45RC thymocytes, and significantly lower numbers of total CD4 + and CD8 + cells in E than in C rats throughout this period-a finding consistent with the significantly lower total number of thymocytes in E than in C rats. The developmental patterns for both markers were similar in E and C groups, in both the rising (days 20 to 28) and declining (days 35 to 48) phases. However, on day 35, E rats had significantly lower numbers of double-positive CD8-TcR and CD8-CD45RC cells than C rats. It therefore seems that FAE tends to accelerate the decline of double-positive CD8-TcR and CD8-CD45RC cells. The contribution of this phenotypic change to the thymic functional alterations induced by FAE remains to be determined.

We previously reported altered responses of thymocytes and splenocytes to mitogen stimulation in fetal alcohol-exposed (FAE) male Sprague-Dawley rats. We also reported enhanced neuroendocrine responses to stressful stimuli in these animals. The experiments we describe herein aimed at testing whether young adult FAE rats manifest a notable dysregulation in the neuroendocrine-immune response to pathogen administration. We tested the effect of in vivo priming of the animal with a low dose of endotoxin [lipopolysaccharide (LPS), 5 micrograms/kg], considered to be suboptimal from the perspective of mounting detectable levels of circulating monokines several hours after administration, upon the production of immunoreactive tumor necrosis factor (TNF-alpha) in response to a further in vitro challenge of peripheral blood mononuclear cells with 2.5 micrograms/ml of LPS 90 min after priming. We show that the response to the LPS pathogen in vitro after priming is significantly blunted (p < 0.01) in male rats exposed prenatally to alcohol, compared with control male animals. FAE female rats and FAE ovariectomized female rats do not show significant differences in the priming response, compared with control animals. We also show that there is no correspondence between plasma corticosterone levels and TNF-alpha production after priming in any of the groups tested.