Social role functioning by adolescents with psychiatric disorders

OBJECTIVE

To identify aspects of social role functioning that are impaired in adolescents with specific psychiatric disorders in order to improve the psychiatric taxonomy and clinical knowledge base.

METHOD

Adolescents in four urban public schools were screened for mental health problems. Structured psychiatric interviews (National Institute of Mental Health Diagnostic Interview Schedule for Children Version 2.2) with 288 adolescents and their mothers were used to identify youths with psychiatric disorders, and 10 aspects of social role functioning were assessed. Aspects of social role functioning that discriminated between youths with and without psychiatric disorders and between those with emotional disorders and those with disruptive disorders were identified for boys and for girls.

RESULTS

Boys with any type of disorder and all youths with disruptive disorders had significant, consistent impairment in academic performance and several other areas of functioning. Youths with emotional disorders, especially girls, demonstrated impairment in social activity participation and peer acceptance, but girls with disorders were not as consistently different from those without as were the boys with emotional disorders.

CONCLUSIONS

Role functioning differs in important ways between youths with and without psychiatric disorders and between girls and boys with disorders. The results underscore the importance of investigating observable aspects of role behavior in order to improve the timely detection and effective management of psychiatric disorders in youth.

Structural modification of an orally active thrombin inhibitor, LB30057: replacement of the D-pocket-binding naphthyl moiety

An amidrazonophenylalanine derivative LB30057 (2) was identified as a potent (Ki = 0.38 nM), selective, and orally active thrombin inhibitor. As a continuation of studies into benzamidrazone-based thrombin inhibitors, we have structurally modified compound 2 by replacing the naphthyl group with a variety of hydrophobic moieties. This study led to discovery of several compounds with significantly enhanced potency in thrombin inhibition without sacrificing selectivity against trypsin and oral absorption. The highest activity was obtained with compound 23 (Ki = 0.045 nM).

Ilio-psoas abscess in the paediatric population: treatment by US-guided percutaneous drainage

BACKGROUND

Image-guided percutaneous drainage has been shown to be a safe and effective alternative to surgery in the management of psoas abscess in adults and adolescents. There is little information on its use in children.

OBJECTIVE

To evaluate the safety and efficacy of US-guided percutaneous needle aspiration and catheter drainage of ilio-psoas abscesses.

MATERIALS AND METHODS

A retrospective review of 14 children with 16 ilio-psoas abscesses (10 pyogenic and 4 tuberculous) who were treated by US-guided percutaneous needle aspiration (n = 5) or catheter drainage (n = 9) along with appropriate antimicrobial therapy.

RESULTS

Percutaneous treatment was successful in 10 of the 14 patients; all showed clinical improvement within 24-48 h of drainage and subsequent imaging demonstrated resolution of the abscess cavities. Surgery was avoided in all of these ten patients except one, who underwent open surgical drainage of ipsilateral hip joint pus. Of the other four patients, two had to undergo surgical drainage of the ilio-psoas abscesses after failure of percutaneous treatment, one improved with antibiotics after needle aspiration failed to yield any pus, and one died of continuing staphylococcal septicaemia within 24 h of the procedure. There were no procedural complications.

CONCLUSIONS

Percutaneous drainage represents an effective alternative to surgical drainage as a supplement to medical therapy in the management of children with ilio-psoas abscesses.

Adolescents' knowledge of their health insurance coverage

PURPOSE

To determine the accuracy of adolescents' self-report of health insurance coverage, using parents' report as a comparison standard.

METHODS

Two separate samples of urban, school-based adolescents and their parents completed self-administered questionnaires about type of health insurance coverage. Sample 1 included 123 and Sample 2 included 93 adolescent-parent pairs. Percent agreement and the kappa statistic were determined for each of the sample groups, and for males versus females and older (> 14 years) versus younger (< or = 14 years) adolescents.

RESULTS

In Sample 1, 33% of adolescent respondents responded "don't know" to the question about type of insurance coverage, and 4% left the question blank; in Sample 2, 3% answered "don't know," with none leaving the question blank. For Sample 1, we found a 57% rate of agreement of adolescents with their parents, and a corresponding kappa of .21. Females and older subjects demonstrated greater accuracy, with kappa's all in the range .13-.29. In Sample 2, 73% of subjects agreed with parents' report, with a kappa of .48. Females and older subjects also demonstrated greater accuracy, with the highest kappa of .59 demonstrated by older females. Excluding those responding with "don't know," we found overall percent agreement with parents of 87% in Sample 1 and 73% in Sample 2; the corresponding kappas were .47 and .51. Females demonstrated higher agreement with parents in both samples. The results stratifying by age were inconsistent. In Sample 1, privately insured subjects were more accurate reporters than those either on medical assistance or uninsured. In Sample 2, no differences were seen by type of insurance.

CONCLUSIONS

Many adolescents do not know their health insurance coverage status. However, for those who did claim to know, acceptable rates of accuracy using both percent agreement and the kappa statistic were demonstrated. Further research is needed to determine how information about insurance is communicated to adolescents and how this knowledge affects access to and use of health services.

Satiation and masticatory function modulated by brain histamine in rats

Both the ventromedial hypothalamus (VMH) and the mesencephalic trigeminal sensory nucleus (Me5) are densely innervated by histaminergic neurons. The depletion of neuronal histamine (HA) from the Me5 by the bilateral microinfusion of 448 nmol/rat alpha-fluoromethylhistidine (FMH), a specific suicide inhibitor of histidine decarboxylase, reduced the eating speed and prolonged meal duration, while leaving the meal size unaffected. HA depletion from the VMH increased the size of the meal and prolonged its duration, but not the eating speed. When the HA turnover rate was measured at 15 min after the scheduled feeding following fasting for less than 24 hr, the rate increased in the region including the Me5, but not in the hypothalamus. The turnover rate reached higher levels at 60 min in both regions. Gastric intubation of an isocaloric liquid diet or an equivolume of water with the liquid diet abolished the increase in HA turnover both in the Me5 region and the hypothalamus. The present findings indicate that brain HA thus modulates satiation through both the VMH and masticatory function as well as due to the action of the Me5. The HA function activated by mastication began earlier in the Me5 and later in the hypothalamus due to a signal originating from the oral proprioceptors and initiated by chewing.

Evolution of magnetic and superconducting fluctuations with doping of high-Tc superconductors

Electronic Raman scattering from high- and low-energy excitations was studied as a function of temperature, extent of hole doping, and energy of the incident photons in Bi2Sr2CaCu2O8+/-delta superconductors. For underdoped superconductors, short-range antiferromagnetic (AF) correlations were found to persist with hole doping, and doped single holes were found to be incoherent in the AF environment. Above the superconducting (SC) transition temperature Tc, the system exhibited a sharp Raman resonance of B1g symmetry and energy of 75 millielectron-volts and a pseudogap for electron-hole excitations below 75 millielectron-volts, a manifestation of a partially coherent state forming from doped incoherent quasi particles. The occupancy of the coherent state increases with cooling until phase ordering at Tc produces a global SC state.

Autonomic and behavioral thermoregulation in guinea pigs during postnatal maturation

Serial experiments were carried out on seven chronically instrumented Hartley-strain guinea pigs at 1, 3, and 5 wk of age to define their autonomic and behavioral thermoregulatory profiles and to test the hypothesis that they have the mechanisms in place shortly after birth that allow them to optimize their energy expenditure for thermoregulation by selecting a thermal environment that requires the lowest metabolic oxygen requirements. Each animal was studied in both a thermocline to determine selected ambient temperature and in a metabolic chamber to determine the thermoregulatory response to forced changes in ambient temperature. In the thermocline, the guinea pigs at all postnatal ages selected an ambient temperature that placed core temperature, oxygen consumption, thermal conductance, heart rate, and respiratory rate at levels comparable to those observed at ambient temperatures in which minimal oxygen consumption occurred in the metabolic chamber. Thus our experiments provide evidence that guinea pigs have the neurophysiological mechanisms in place shortly after birth that allow them to optimize their energy expenditure for thermoregulation by selecting a thermal environment that corresponds to the lowest metabolic oxygen requirements.

Release of glutathione from erythrocytes and other markers of oxidative stress in carbon monoxide poisoning

Rats exposed to CO in a manner known to cause oxidative stress in brain exhibited a twofold increase in plasma levels of oxidized proteins, thiobarbituric acid-reactive substances (TBARS), oxidized glutathione (GSSG), and reduced glutathione (GSH). Changes were neither directly related to hypoxic stress from carboxyhemoglobin nor significantly influenced by circulating platelets or neutrophils. Treatment with the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester inhibited elevations in GSH and GSSG but not changes in oxidized proteins or TBARS, suggesting that two oxidative mechanisms may be operating in this model and that GSH and GSSG elevations involved nitric oxide-derived oxidants. Elevations of blood GSH and GSSG occurred at different anatomic sites, indicating that no single organ was the source of the increased peptides. Animals that underwent exchange transfusion with a hemoglobin-containing saline solution did not exhibit elevations in GSH and GSSG, suggesting that blood-borne cells released these peptides in response to oxidative stress. In in vitro studies, erythrocytes, but not platelets and leukocytes, responded to oxidative stress from peroxynitrite by releasing GSH, whereas no release was observed in response to nitric oxide or superoxide. Glucose, maltose, and cytochalasin B, agents that protect extracellular components of the hexose transport protein complex from oxidative stress, prevented GSH release. The data indicate that nitric oxide-derived oxidants are involved in CO-mediated oxidative stress within the vascular compartment and that elevations of several compounds may be useful for identifying exposures to CO likely to precipitate brain injury.

Ki-67, p53, and Bcl-2 expression of serrated adenomas of the colon

To investigate epithelial cell proliferation and oncoprotein expression of the serrated adenoma, a term that has been used synonymously with mixed hyperplastic and adenomatous polyp, immunohistochemical staining using polyclonal antibodies against Ki-67 and p53, and a Bcl-2 monoclonal antibody, was performed and the results compared with those in hyperplastic polyps and tubular adenomas. A total of 20 serrated adenomas all characterized by a serrated glandular pattern, contained immature goblet cells, upper crypt zone mitotic figures, and a few nucleoli within the epithelial cells. Twenty hyperplastic polyps and 20 tubular adenomas (all with low-grade dysplasia) were examined, and lesions that contained separate areas of hyperplastic and adenomatous glands were excluded. The Ki-67-positive rate in the middle zone of the crypts in serrated adenomas was significantly higher than in hyperplastic polyps but lower than in tubular adenomas; a similar tendency was also noted for the upper zone. Both serrated adenomas and hyperplastic polyps demonstrated Bcl-2-positive reactivity that was essentially limited to the lower crypt zone, while in contrast, involvement in tubular adenomas often extended to the middle zone. No p53 overexpression was found in any category. These results suggest that serrated adenomas may be committed to independent growth.

The impact of asthma on the health status of adolescents

OBJECTIVE

To identify a characteristic pattern of health and illness for adolescents with asthma, we compared the health status of teenagers with asthma to those without asthma using a recently developed generic health status instrument, the Child Health and Illness Profile, Adolescent Edition (CHIP-AE).

METHODS

This was a cross-sectional survey using a school sample of 3109 teenagers. Participants completed the CHIP-AE during school in northern Baltimore City, rural western Maryland, and rural Arkansas. The health and functioning scores of teens without asthma ("well" group) were compared with those with asthma with and without recent wheezing.

RESULTS

Of the 12% who reported that a physician had ever told them they had asthma, 50% had problems with wheezing in the past 28 days. Compared with well teenagers, those with asthma and recent wheezing had lower perceived well-being, more physical and emotional symptoms, greater limitations in activity, more comorbidities, and more negative behaviors that threaten social development. These findings held true in multivariable regression models that controlled for sociodemographics and sites of data collection. Teenagers with asthma without recent wheezing reported a greater number of comorbidities than well teens and showed similar trends in health status as those with recently symptomatic asthma.

CONCLUSIONS

Multiple aspects of adolescent health status are affected by asthma, particularly if it is recently symptomatic. These results argue for incorporating a generic health status instrument, such as the CHIP-AE, in studies that document the health needs or outcomes of medical care for populations of teenagers with asthma.

Percutaneous transluminal balloon pulmonary valvuloplasty using domestic balloon catheter for congenital pulmonary valve stenosis in children

OBJECTIVE

To estimate the effect of percutaneous balloon pulmonary valvuloplasty (PBPV) using domestic balloon catheter for congenital pulmonary valve stenosis (PVS) in infants and children.

PATIENTS AND METHODS

The data of 70 patients aged from 1.5 to 12 years (mean 5.5 +/- 3.4 years) who underwent PBPV using domestic balloon catheter for PVS in our institution were reviewed. Sixty-six patients had dome-shaped valve stenosis, and 4 had displastic valve stenosis. SaO2 reduced in 5 patients and associated open foramen ovale was noted in 23. Predilatation, right ventricular systolic pressure ranged from 60 to 234 mmHg (mean 115.75 +/- 36.15 mmHg). The systolic gradient (delta P) from right ventricle to pulmonary artery was 89.92 +/- 38.25 mmHg. Balloon diameter was selected 120%-142% of pulmonary valve annulus diameter (mean 132%). All patients were followed up for 3 months-4 years by means of clinical examination. ECG, 2D-UCG, and Doppler-UCG.

RESULTS

After dilatation, delta P reduced from 89.92 +/- 38.25 to 14.65 +/- 11.40 mmHg (P < 0.001). The rate of decrease in transvalve gradient (delta P) was 83.7%. No patients experienced procedure-related events. Mid-term follow-up showed that no patients had clinical and instrumental complications. Doppler and ECG analyses showed that delta P did not change significantly similar to immediate gradient after PBPV and right ventricular hypertrophy disappeared progressively 6 months after PBPV.

CONCLUSIONS

PBPV is a useful, safe and definitive procedure in the treatment of isolated PVS in infants and children. The properties and features of the balloon catheter produced by Shanghai Med-Tech Factory are similar to those of Med-Tech balloon catheter of U.S.A.

Stability and folding of precursor and mature tryptophan-substituted ribose binding protein of Escherichia coli

A mutant ribose binding protein (RBP) of Escherichia coli was obtained by site-directed mutagenesis, replacing Phe-187 in the wild-type RBP (WT-RBP) with a Trp residue, in order to compare its stability and folding behavior with those of the WT-RBP. The equilibrium unfolding properties and the folding kinetics of these proteins were monitored by fluorescence and circular dichroism (CD). For both WT-RBP and the Trp-substituted RBP (Trp-RBP), the conformational stabilities of the precursor proteins and the mature proteins were the same, indicating that the signal peptide had no influence on the property of the mature domain. The Phe/Trp substitution in the mature domain, however, brought about a significant decrease in the conformational stability. The signal peptide had an appreciable retarding effect on the folding of the precursor Trp-RBP as was reported for the WT-RBP. Refolding kinetics of the WT-RBP and Trp-RBP showed a two-step reaction when monitored by fluorescence and by CD.

Persistent reduction of GABA(A) receptor-mediated inhibition in rat hippocampus after chronic intermittent ethanol treatment

GABA(A) receptor-mediated function was studied in rats treated with chronic intermittent ethanol (CIE). Rats were given 60 doses of 6g/kg ethanol every 24 h by gastric intubation, with repeated intoxicating and withdrawal episodes leading to a kindling-like increase in seizure susceptibility (Kokka et al., Alcohol: Clin. Exp. Res., 17 (1993) 525-531). Efflux of 36Cl-, evoked by application of muscimol, a measure of GABA(A) receptor function, was examined in 300 mu m slices obtained from frontal, parietal, and temporal cortex, hippocampus, and inferior colliculus, one day after the last administration of ethanol. Compared to controls, the 36Cl- efflux in hippocampal slices of CIE rats was significantly reduced by 29%, while there were no changes in the other brain regions studied. In hippocampal slices, paired-pulse inhibition in CA1 pyramidal neurons, measured extracellularly using homosynaptic orthodromic stimulation at an interval of 10 ms, was significantly reduced in CIE rats. A significant decrease by 40% both at 2 and 40 days after 60 doses of ethanol was found, implying a persistent decrease in GABA(A) receptor-mediated inhibition in CIE rats. These reductions in paired-pulse inhibition are consistent with the decrease in the pentylenetetrazol (PTZ) seizure threshold which was previously observed in CIE rats. Therefore, we suggest that this reduction of GABA(A) receptor-mediated inhibition contributes to the persistent increase in seizure susceptibility of CIE rats.

Hypothalamic neuronal histamine modulates physiological responses induced by interleukin-1 beta

Dynamic involvement of hypothalamic histamine in ingestive behavior and thermogenesis induced by interleukin-1 beta (IL-1 beta) was examined in rats. Intraperitoneal injection of 0.12 nmol/rat IL-1 beta decreased food and water intake and elevated body temperature. However, depletion of neuronal histamine induced by intraperitoneal injection of 160 mumol/rat alpha-fluoromethylhistidine, a suicide inhibitor of histidine decarboxylase (HDC), attenuated the suppressive effect of IL-1 beta on food intake, facilitated the suppressive effect on drinking, and enhanced the elevating effect on rectal temperature. Intraperitoneal injection of 0.12 nmol/rat IL-1 beta increased hypothalamic histamine turnover rate. The same dose of IL-1 beta also increased activity of HDC and histamine-N-methyltransferase (HMT). These results suggest that IL-1 beta may stimulate synthesis and release of hypothalamic histamine in presynaptic terminals by activation of HDC and facilitate degradation of extracellular histamine by activation of MHT. These changes in the dynamics of hypothalamic histamine modulate IL-1 beta-induced ingestive behavior and body temperature.

Hypothalamic neuronal histamine modulates adaptive behavior and thermogenesis in response to endogenous pyrogen

Homeostatic involvement of hypothalamic neuronal histamine in adaptive behavior and thermogenesis was investigated when interleukin-1 beta (IL-1 beta), one of the endogenous pyrogens, was infused peripherally in rats. IL-1 beta decreased food and water intake and elevated body temperature. Depletion of neuronal histamine in the hypothalamus induced by alpha-fluoromethylhistidine, a suicide inhibitor of the histamine synthesizing enzyme histidine decarboxylase (HDC), attenuated the suppressive effect of IL-1 beta on food intake, facilitated the inhibitory effect on water intake, and enhanced its thermogenic effect. Simultaneously IL-1 beta increased activity of HDC and histamine-N-methyltransferase (HMT), a neuronal histamine catabolizing enzyme. Pretreatment with indomethacin completely blocked those increases in turnover of neuronal histamine induced by IL-1 beta. Hypothalamic prostaglandin E2 (PGE2) activated by peripheral IL-1 beta, but not peripheral PGE2, increased both activities of HDC and HMT. Ginsenoside Rg1, a major component of panax ginseng, modulated the suppressive effects of IL-1 beta on ingestive behavior, resulting in a lowering of body temperature. The findings suggest that the effects of IL-1 beta on ingestive behavior and thermogenesis may be modulated by dynamics of hypothalamic neuronal histamine through activation of hypothalamic PGE2 which is elevated by peripheral IL-1 beta.

Zinc modulation of GABAA receptor-mediated chloride flux in rat hippocampal slices

We studied the effect of ZnCl2 application on GABAA receptor-mediated 36CI- flux in microsacs prepared from whole rat hippocampus and in region-specific hippocampal slices. Slices were obtained from the dentate gyrus (DG), which contains the zinc-enriched hilar region, and from the CA1 region which contains lower levels of endogenous zinc. Muscimol (10 microM)-evoked 36Cl- flux was significantly reduced by ZnCl2 (100 microM) in hippocampal microsacs. In hippocampal slices, muscimol (50 microM)-evoked 36Cl- efflux was higher in CA1 (112.5 +/- 27.9% above basal efflux rate) than in DG slices (29.7 +/- 5.6%). In the presence of ZnCl2, the muscimol effect on efflux rate in CA1 and DG regions was decreased to 10.6 +/- 5.4% and 6.9 +/- 4.9%, respectively. Preincubation with the zinc chelator, tetrakis(2-pyridylmethyl)ethylenediamine (TPEN, 20 microM), caused a significant increase in muscimol-evoked 36Cl- efflux only in DG slices (57.2 +/- 7.0%), suggesting that GABAA receptors in the DG of rat hippocampus under physiological conditions may function under the inhibitory influence of endogenous chelatable zinc. In intracellular recordings, ZnCl2 (100 microM) application had no effect on the responses to GABA applied perisomatically or in the dendritic region of CA1 neurons. The lack of Zn2+ effect on the postsynaptic GABAA receptor-mediated responses suggests that the decreases of the 36Cl- efflux observed in the biochemical assays may be due to zinc action on neurons other than the principal pyramidal CA1 cells, and possibly the non-neuronal cell populations.

Histamine effect on ornithine decarboxylase of rat intestine in cases of ischemia-reperfusion compared with refeeding

Our previous study suggested that histamine might enhance the increase of ornithine decarboxylase activity in injured intestinal mucosa. To test this hypothesis, we measured histamine content in mesenteric lymph and ornithine decarboxylase activity in intestinal mucosa after ischemia-reperfusion in the rat. We examined the effect of alpha-fluoromethylhistidine, a suicide inhibitor of histidine decarboxylase, on ornithine decarboxylase activity after ischemia-reperfusion and compared this with its effect on the rat after refeeding. Ischemia-reperfusion was performed by 15-min occlusion of the superior mesenteric artery. After ischemia-reperfusion, histamine content in mesenteric lymph increased, and this increase was completely suppressed by alpha-fluoromethylhistidine pretreatment. In contrast to ischemia-reperfusion, histamine content in mesenteric lymph did not change after refeeding. Ornithine decarboxylase activity increased markedly 3 and 6 hr after ischemia-reperfusion and refeeding, whereas alpha-fluoromethylhistidine attenuated the increase in ornithine decarboxylase activity only in the ischemia-reperfusion group. These results indicate that increase in histamine synthesis in the intestinal mucosa plays an important role in the increase of ornithine decarboxylase activity after ischemia-reperfusion but that histamine is not related to the increase in ornithine decarboxylase activity after refeeding.

Ginsenoside Rg1 modulates ingestive behavior and thermal response induced by interleukin-1 beta in rats

Effects of ginsenoside Rg1 (Rg1), a major component of panax ginseng, on changes in ingestive behavior and rectal temperature induced by interleukin-1 beta (IL-1 beta) were investigated in rats. Intraperitoneal (ip) injection of IL-1 beta suppressed food and water intake and elevated rectal temperature. The suppressive effect of IL-1 beta on water intake was converted to an increase when 4.0 mM Rg1 was continuously infused into the third cerebroventricle (ICV) at a rate of 0.966 microliters/h. The elevation of rectal temperature induced by IL-1 beta was attenuated by ICV infusion of Rg1. The feeding suppression caused by IL-1 beta was unaffected by ICV infusion of Rg1. These results suggest that sustained ICV infusion of Rg1 may modulate the effects of IL-1 beta on ingestive behaviors, i.e., increase in water intake and sustained decrease in food intake, resulting in a lowering of body temperature.

Role of histamine receptors in intestinal repair after ischemia-reperfusion in rats

BACKGROUND/AIMS

Previously, we showed that an elevated production of histamine promotes the healing of injured intestinal mucosa after ischemia-reperfusion. The aim of the present study was to determine whether histamine-mediated repair of the intestinal mucosa after ischemia-reperfusion involves the engagement of H1 or H2 receptors.

METHODS

The superior mesenteric artery was occluded for 15 minutes followed by reperfusion, and H1- or H2-receptor antagonists were infused intraduodenally. After ischemia-reperfusion, ornithine decarboxylase activity in the jejunal mucosa and lipid transport to mesenteric lymph were examined.

RESULTS

In jejunal mucosa, ornithine decarboxylase activity markedly increased at 6 hours after reperfusion and remained elevated at 48 hours. The ischemia-reperfusion-induced increase in ornithine decarboxylase activity was attenuated (in a dose-dependent manner) by an H1-receptor antagonist (chlorpheniramine maleate) but not by an H2 antagonist (cimetidine). Intraperitoneal injection of an H3 antagonist (thioperamide) increased histamine output in mesenteric lymph and stimulated intestinal ornithine decarboxylase activity. Transport of dietary lipid into mesenteric lymph was depressed 24 hours after an ischemic insult, yet it returned to the normal level 48 hours after ischemia-reperfusion. The recovery of the lipid transport normally observed at 48 hours after ischemia-reperfusion was attenuated by the H1 antagonist.

CONCLUSIONS

The beneficial effects of histamine on the repair of intestinal mucosa after ischemia-reperfusion results from the engagement and activation of the H1 receptor.

2-deoxy-D-glucose suppresses food intake through activation of hypothalamic histamine in rats

The aim of this experiment was to demonstrate whether brain histamine contributes to delayed suppression of food intake after administration of 2-deoxy-D-glucose (2-DG). Food intake decreased significantly for 48 h after infusion of 2-DG into the rat third cerebroventricle. This delayed decrease in food intake was abolished by depletion of neuronal histamine by intraperitoneal pretreatment with alpha-fluoromethylhistidine (160 mumol/rat), a suicide inhibitor of a histamine-synthesizing enzyme. Intracerebroventricular infusion of 24 mumol 2-DG accelerated turnover rate of hypothalamic histamine. These results indicate that the delayed feeding suppression by 2-DG is modulated through histaminergic neurons in the hypothalamus. This histaminergic response may be related, at least in part, to homeostatic control of energy metabolism in the brain.

Thermoregulation and hypothalamic histamine turnover modulated by interleukin-1 beta in rats

To clarify the involvement of hypothalamic histamine in thermogenic response provoked by high ambient temperature, or interleukin-1 beta (IL-1 beta), changes in rectal temperature and histamine turnover were investigated. Rectal temperature was maintained normally after exposure to high ambient temperature, but elevated by IL-1 beta. In spite of these different responses of body temperature, hypothalamic histamine turnover was increased in each treatment. The results suggest that hypothalamic histaminergic neurons are activated not only peripherally by high ambient temperature, but also centrally by IL-1 beta as endogenous pyrogen.

Aminoglucose-induced feeding suppression is regulated by hypothalamic neuronal histamine in rats

Central mechanisms involved in feeding suppression produced by 1-deoxy-D-glucosamine (1-DGlcN) and 1-deoxy-N-acetylglucosamine (1-DGlcNAc) are unclear. To clarify the mechanisms, we investigated the role of hypothalamic neuronal histamine (HA) in feeding suppression induced by 1-DGlcN and 1-DGlcNAc in rats. Food intake was suppressed for 3 days after a single infusion of 24 mumol 1-DGlcN into the third cerebroventricle (i.c.v.). Depletion of presynaptic HA due to intraperitoneal infusion (i.p.) of alpha-fluoromethylhistidine (FMH), a specific inhibitor of the HA synthesizing enzyme histidine decarboxylase (HDC), abolished feeding suppression completely. Blockade of postsynaptic H1-receptors by i.p. injection of 26 mumol chlorpheniramine also abolished the suppression. Oral administration of 2.4 mmol 1-DGlcNAc suppressed food intake. However, depletion of neuronal HA due to FMH did not affect the suppression. I.c.v. infusion of 24 mumol 1-DGlcN increased turnover rate of HA at 1 h after the infusion. Hypothalamic HA concentration, but not that of tele-methylhistamine (t-MH), increased at 24 h after i.c.v. infusion of 1-DGlcN, which suggests a correlation between HA concentration and the behavioral response. These results indicate that 1-DGlcN, but not 1-DGlcNAc, modulates feeding suppression through HA neurons in the hypothalamus. Differences in mechanisms of feeding suppression by these aminoglucoses may depend on the principal sites of action in the brain and/or peripheral organs.

Abnormalities in obese Zuckers: defective control of histaminergic functions

Histaminergic functions in the hypothalamus of Zucker obese rats were investigated. Blockade of postsynaptic H1-receptor after infusion of chlorpheniramine into the third cerebroventricle (ICV) failed to affect feeding in obese Zuckers, although feeding was potently elicited in Wistar King A control rats. Presynaptic increase in histamine by an H3-receptor antagonist, thioperamide, suppressed feeding in Wistar controls, but not in obese Zuckers. Under high ambient temperature, Wistar controls decreased food intake and maintained their rectal temperature normally. However, obese Zuckers and histamine depleted rats due to alpha-fluoromethyl-histidine (FMH), a specific "suicide" inhibitor of a histamine synthesizing decarboxylase enzyme (HDC), failed to show this decrease in food intake as adaptive behavior. Their rectal temperature concomitantly elevated in response to heated circumstance. ICV infusion of thioperamide increased the blood glucose level in Wistar controls, but not in obese Zuckers. The defect in all these regulatory functions found in obese Zuckers may be derived from an excessive decrease in hypothalamic histamine content due to inactivity of HDC. The histamine-depleted model sufficiently mimicked the abnormalities in obese Zuckers.

Circadian rhythms and patterns of running-wheel activity, feeding and drinking behaviors of old male rats

Running-wheel activity of 7 young adult male rats (3 to 6.5 months of age) and 11 old male rats (22 to 34 months of age), feeding behavior of 10 each of young adult and old male rats and drinking behavior of 6 each of young adult and old male rats were recorded. Circadian rhythms were lost in 2, 6 and 1 old rats respectively in running activity, feeding and drinking behaviors. Loss of circadian rhythm of three behaviors seems not to occur concomitantly. Although the remaining old rats still showed as high a percentage of nocturnal activities in these three behaviors as young rats, the patterns of the behaviors revealed age-related changes. Old rats had decreased daily activity with small numbers and short duration of bursts of activity. Total frequencies of the head of rats interrupting the photobeam of a feeder during 24 hour period increased in old age with patterns of a small number of long meals with a rapid ingestion rate. Total numbers of licking the spout per day increased in old rats with patterns of a small number of short duration draft with a rapid licking rate. Old rats still maintained diurnal difference of drinking-to-feeding ratio. The similarity of the feeding and drinking patterns between old male rats and ventromedial hypothalamus lesioned rats was discussed.