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Background: Laminopathies are a group of rare genetic disorders characterized by multiple-tissue degeneration. We describe a new laminopathy with ovarian cystadenoma and explore its molecular etiology., Methods: The case is a 15-year-old girl who presents the prominent progeroid disorders, multiple system degeneration and early-onset cystadenoma of the ovary. Candidate genes including LMNA, ZMPSTE24, PPAR G, INSR and WRN were sequenced to screen for DNA variants. The mRNA and protein expression levels of LMNA were examined in primary fibroblasts. The pathophysiological events such as morphologic alterations, cell senescence, cell proliferation, apoptosis and pRb as well as p53 protein expressions were also investigated in primary fibroblasts., Results: No mutation was identified in the candidate genes screened. Nuclear abnormalities including nuclear blebs, mislocalization of lamin A/C were evident in the patient fibroblasts. Ultrastructurally, nucleus exhibited nuclear herniation and almost complete loss of peripheral heterochromatin. In addition, lamin C protein expression was markedly reduced whereas lamin A protein level was normal and no prelamin A was detected in the primary fibroblasts. Although the senescence-associated beta-galactosidase staining of patient' cells was negative, cells in S phase increased in accompany with a decrease in pRb protein expression. Furthermore, increases in apoptotic cell death and p53 expression were observed., Conclusions: Our data suggest that selective deficiency of lamin C protein is associated with a case of laminopathy with ovarian cystadenoma. The abnormalities in nuclear structure and alterations in gene expression such as the decrease in pRb and increase in p53 may be responsible for the multiple tissue degeneration.

Aim: To investigate nicotinamide's action on glucose metabolism, and the association between niacin consumption and obesity prevalence., Methods: Dynamic nicotinamide's effect on plasma hydrogen peroxide and glucose metabolism was investigated using oral glucose tolerance tests with or without nicotinamide in the same five healthy subjects. Lag-regression analysis was used to examine the association between the niacin consumption and the obesity prevalence among US children using the data from the Economic Research Service of the US Department of Agriculture and from US Centers for Disease Control and Prevention, respectively., Results: Compared with the control oral glucose tolerance test, the 1-h plasma hydrogen peroxide (1.4 +/- 0.1 micromol/L vs 1.6 +/- 0.1 micromol/L, P = 0.016) and insulin levels (247.1 +/- 129.0 pmol/L vs 452.6 +/- 181.8 pmol/L, P = 0.028) were significantly higher, and the 3-h blood glucose was significantly lower (5.8 +/- 1.2 mmol/L vs 4.5 +/- 1.1 mmol/L, P = 0.002) after co-administration of glucose and 300 mg nicotinamide. The obesity prevalence among American children increased with the increasing per capita niacin consumption, the increasing grain contribution to niacin due to niacin-fortification, and the increasing niacin-fortified ready-to-eat cereal consumption, with a 10-year lag. The regression analyses showed that the obesity prevalence in the US children of all age groups was determined by niacin consumption (R(2) = 0.814, 0.961 and 0.94 for 2-5 years, 6-11 years and 12-19 years age groups, respectively)., Conclusion: The appetite-stimulating effect of nicotinamide appears to involve oxidative stress. Excess niacin consumption may be a major factor in the increased obesity prevalence in US children.

Objective: To examine the effects of cocaine on the activities of ATPase, LDH and SDH in cultured mouse splenocytes in vitro., Methods: The ATPase, LDH and SDH activities in mouse splenocytes were detected at day 7 after continuous culturing the mouse cells exposed to cocaine hydrochloride in final concentration of 10, 20 and 100 microg/mL in vitro., Results: The activities of ATPase, LDH and SDH in mouse splenocytes exposed to cocaine hydrochloride in final concentration of 10, 20 and 100 microg/mL were significantly decreased after continuous culturing for 7 days., Conclusion: The present study demonstrated that cocaine could inhibit the activities of ATPase, LDH and SDH in cultured splenocytes in vitro.

Aim: To evaluate whether insulin intervention could affect the metabolic and endocrine functions of adipose tissue., Methods: C57BL/6 mice were fed on a high-fat-diet for 12-16 weeks to induce insulin resistance. Insulin intervention was administered in the high-fat-diet mice for 4 weeks at 12 weeks (early insulin treatment) or 16 weeks (late insulin treatment). Intraperitoneal glucose tolerance tests were performed before and after insulin treatment. Expression levels of factors involved in the triglyceride synthesis and endocrine functions of adipose tissue including phosphoenolpyruvate carboxykinase (PEPCK-C), fatty acid synthase (FAS), aquaporin 7 (AQP7), adiponectin, visfatin, and interleukin-6 (IL-6) were determined by Western blot., Results: In the obese mice, glucose tolerance was impaired; triglyceride content was increased in the liver tissue; protein expression of FAS and adiponectin was decreased; expression of visfatin was increased in adipose tissue. After 4-week insulin treatment, glucose tolerance was improved; triglyceride content was decreased in the liver and skeletal muscle; expression of PEPCK-C, FAS, and adiponectin was increased in the adipose tissue; IL-6 and AQP7 expression was reduced in the fat. Early insulin treatment had better effect in increasing the expression of FAS and PEPCK-C and decreasing the expression of IL-6., Conclusion: These results indicate that insulin can target adipocytes for improvement of insulin sensitivity through stimulating triglyceride synthesis and partly improving endocrine functions.

Type 2 diabetes is a major global health problem. It is generally accepted that type 2 diabetes is the result of gene-environmental interaction. However, the mechanism underlying the interaction is unclear. Diet change is known to play an important role in type 2 diabetes. The fact that the global high prevalence of type 2 diabetes has occurred following the spread of food fortification worldwide suggests a possible involvement of excess niacin intake. Our recent study found that nicotinamide overload and low nicotinamide detoxification may induce oxidative stress associated with insulin resistance. Based on the relevant facts, this review briefly summarized the relationship between the prevalence of type 2 diabetes and the nicotinamide metabolism changes induced by excess niacin intake, aldehyde oxidase inhibitors, liver diseases and functional defects of skin. We speculate that the gene-environmental interaction in type 2 diabetes may be a reflection of the outcome of the association of chronic nicotinamide overload-induced toxicity and the relatively low detoxification/excretion capacity of the body. Reducing the content of niacin in foods may be a promising strategy for the control of type 2 diabetes.

Objective: It was reported that a negative feedback loop might exist between peroxisome proliferator-activated receptor alpha (PPARalpha) and glucocorticoid receptor (GR). However, it is unclear whether GR expression is regulated by PPARalpha activation. To further demonstrate this possibility, we conducted the present study to investigate the regulatory effects of the PPARalpha agonist fenofibrate on GR expression in Sprague-Dawley rats., Methods: GR gene and protein expression levels were determined in liver, visceral and muscle tissues. Adrenal 11beta-hydroxylase (CYP11B1) expression was examined by RT-PCR and circulating corticosterone level was measured by RIA method., Results: GR expression was reduced by fenofibrate in a time- and does-dependent manner. The GR mRNA in the three fenofibrate groups of rats were 55% (FE1), 54% (FE2) and 68% (FE3) lower than that of the control rats. The GR protein were 28%, 77% and 99% lower than the control. The inhibition was observed in liver, but not in fat and muscle. The corticosterone level in the blood was increased significantly by fenofibrate(the levels of corticosterone in control, FE1, FE2, FE3, MK886 groups were (393 +/- 23), (495 +/- 44), (516 +/- 18), (622 +/- 93), (382 +/- 37) ng/ml respectively. These effects of fenofibrate were abolished by PPARalpha inhibitor MK886, suggesting that fenofibrate activated through PPARalpha., Conclusion: A new molecular mechanism has been found for a negative feedback regulation of GR activity by PPARalpha in SD rats.

Aim: To investigate whether nicotinamide overload plays a role in type 2 diabetes., Methods: Nicotinamide metabolic patterns of 14 diabetic and 14 non-diabetic subjects were compared using HPLC. Cumulative effects of nicotinamide and N(1)-methylnicotinamide on glucose metabolism, plasma H(2)O(2) levels and tissue nicotinamide adenine dinucleotide (NAD) contents of adult Sprague-Dawley rats were observed. The role of human sweat glands and rat skin in nicotinamide metabolism was investigated using sauna and burn injury, respectively., Results: Diabetic subjects had significantly higher plasma N(1)-methylnicotinamide levels 5 h after a 100-mg nicotinamide load than the non-diabetic subjects (0.89 +/- 0.13 micromol/L vs 0.6 +/- 0.13 micromol/L, P < 0.001). Cumulative doses of nicotinamide (2 g/kg) significantly increased rat plasma N(1)-methylnicotinamide concentrations associated with severe insulin resistance, which was mimicked by N(1)-methylnicotinamide. Moreover, cumulative exposure to N(1)-methylnicotinamide (2 g/kg) markedly reduced rat muscle and liver NAD contents and erythrocyte NAD/NADH ratio, and increased plasma H(2)O(2) levels. Decrease in NAD/NADH ratio and increase in H(2)O(2) generation were also observed in human erythrocytes after exposure to N(1)-methylnicotinamide in vitro. Sweating eliminated excessive nicotinamide (5.3-fold increase in sweat nicotinamide concentration 1 h after a 100-mg nicotinamide load). Skin damage or aldehyde oxidase inhibition with tamoxifen or olanzapine, both being notorious for impairing glucose tolerance, delayed N(1)-methylnicotinamide clearance., Conclusion: These findings suggest that nicotinamide overload, which induced an increase in plasma N(1)-methylnicotinamide, associated with oxidative stress and insulin resistance, plays a role in type 2 diabetes.

Objective: To investigate the effect of early insulin therapy on NF-kappaB pathway and inflammatory cytokine responses in liver of diabetic rat., Methods: NF-kappaB p65 DNA binding was assayed with ELISA-based assay kit, cytokine gene expressions were quantified with real-time PCR and phosphoenolpyruvate carboxykinase (PEPCK), NF-kappaB and inhibitor kappaB (IkappaBalpha) protein levels were assayed with Western blot. Results Compared with control, hepatic PEPCK protein level in the untreated diabetic rat increased by 40%. Early insulin and gliclazide treatment normalized PEPCK protein level. The abundance of IkappaBalpha protein was significantly decreased and nuclear NF-kappaB p65 DNA binding activity was increased in untreated diabetic rats. IkappaBalpha protein content increased and NF-kappaB p65 DNA binding decreased during early intervention treatment. mRNAs encoding IL-1beta and TNFalpha were increased, which were reduced to normal levels after insulin and gliclazide treatment., Conclusions: It is suggested that early insulin treatment inhibits NF-kappaB activity and inflammatory cytokine responses in liver that are involved in the amelioration of insulin resistance in diabetic rats. Such results might be due to indirect antiinflammatory effects of insulin thus relieving glucotoxicity and lipotoxicity in peripheral tissues.

Objective: To investigate the effect of early insulin therapy on the nuclear factor kappaB (NF-kappaB) pathway and inflammatory cytokine responses in skeletal muscle in type 2 diabetes mellitus (DM)., Methods: SD rats underwent intraperitoneal injection of streptozotocin to establish DM models and then divided into 5 groups: early un-treated group, early gliclazide treated group (receiving gliclazide since the third day after blood glucose increase for 3 weeks for 3 weeks), early insulin treated group (receiving insulin since the third day after blood glucose increase for 3 weeks for 3 weeks), late un-treated group, and late insulin treated group (receiving insulin since the fourth week after blood glucose increase for 3 weeks). By the end of treatment the rats were killed. Homogenate of skeletal muscle was made. The NF-kappaB P65 DNA binding was assayed by ELISA-based assay kit. Real time PCR was used to detect the mRNA expression levels of the gene of the cytokines: glucose transporter 4 (Glut4), inhibitor kappaB (IkappaBalpha), IL-1beta, IL-6, and tumor necrosis factor (TNF)-alpha. And Glut4 and IkappaBalpha protein expression levels were assayed by Western blotting., Results: The Glut4 mRNA level in the skeletal muscle of the untreated DM rats decreased by 59% and the Glut4 protein level in the muscle cell membrane decreased by 69%. Insulin treatment and gliclazide treatment increased the Glut4 mRNA expression by 17% and 13% respectively, increased the Glut4 protein expression in cell membrane by 23% and 10% respectively, and decreased the Glut4 protein expression in the cytoplasm. In the DM rats the IkappaBalpha protein expression in the skeletal muscle was significantly lower (P < 0.05) and the NF-kappaB P65 DNA binding activity increased, and TNF-alpha, IL-1B, and IL-6 expression levels were up-regulated in comparison with the normal control group. Early treatment of insulin and gliclazide increased the IkappaBalpha protein expression, decreased the NF-kappaB P65 DNA binding activity and the TNF-alpha expression in the skeletal muscle., Conclusion: Early insulin treatment inhibits the NFkappaB activity and inflammatory cytokine responses in skeletal muscle that are involved in the amelioration of insulin resistance in type 2 DM. Such results may be due to indirect antiinflammatory effects of insulin relieving glucotoxicity and lipotoxicity in peripheral tissues.

To clarify the effect of early insulin therapy on nuclear factor kappaB (NFkappaB) pathway and inflammatory cytokine responses in the liver and skeletal muscle in type 2 diabetes. High-fat diet and low dose streptozotocin (STZ) induced diabetic rats were given NPH insulin or gliclazide for 3 weeks initiated at the 3rd day after STZ injection as early treatment and NPH for 3 weeks at 1 month as late treatment. Intraperitoneal glucose tolerance test (IPGTT) was performed at 3rd day after the end of treatment. Early interventions caused a decrease in glucose-insulin index in IPGTT, promoted glucose transporter 4 (Glut4) gene and protein expressions in muscle and reduced phosphoenolpyruvate carboxykinase (PEPCK) protein levels in the liver. There was an increase in inhibitor kappaB (IkappaBalpha) protein and a decrease in NFkappaB p65 DNA binding activity. A decreased level in mRNAs encoding tumor necrosis factor (TNF)alpha in the liver and muscle and interleukin (IL)-1beta in the liver were observed. Our results suggested that early insulin treatment inhibits NFkappaB activity and inflammatory cytokine responses in the liver and skeletal muscle that were involved in the amelioration of insulin resistance in type 2 diabetic rats.

Objective: To investigate the relationship between brachial-ankle pulse wave velocity (baPWV) and different stage of cardiac dysfunction., Methods: 253 consecutive patients with coronary atherosclerotic heart disease were enrolled from August 2006 to February 2007. Patients were grouped according to the functional classification of New York Heart Association (NYHA). The baPWV was measured non-invasively with a VP1000 automated PWV/ABI analyzer (PWV/ABI, Colin CO. Ltd., Komaki, Japan). At the same time, BNP, EF, LAEDV and LVESV were measured in all the patients., Results: Brachial-ankle PWV was significantly correlated with cardiac function classification of NYHA (r = 0. 444, P < 0.001), BNP( r = 0.394, < 0.001) and left ventricular end diastolic volume (r = - 0.130, P < 0.05). The under area of receiver operating charachateistic (ROC) curve was 73.9%. The ROC curve demonstrated that when the value of brachial-ankle PWV was equal to or larger than 1717 cm/s (> 1717 cm/s), the sensitivity of diagnosing mild cardiac dysfunction was 72.9% and specifity 61.8%. When its value was equal to or larger than 1900 cm/s (> or = 1900 cm/s), the sensitivity and specificity were 61.5% and 81.9% respectively., Conclusion: Brachial-ankle PWV is significantly correlated to the NYHA classification of heart failure and it may be a prospective index to diagnose early stage of cardiac dysfunction.

Objective: To compare the effect of continuous and discontinuous density gradient centrifugation for purification of human pancreatic islets with COBE 2991 cell processor., Methods: Human pancreases were obtained from brain-dead donors and stored in cold UW solution. The connective tissues were removed from the pancreases, and the pancreatic ducts were perfused with a cold enzyme (Liberase). The islets were then separated by gentle mechanical dissociation and purified with discontinuous (10 pancreases) or continuous (8 pancreases) gradients of HCA-Ficoll in COBE 2991 cell processor. Samples were collected in duplicate for determination of the quantity of islets, islet equivalents (IEQ), and the purity., Results: The weights of the pancreases before and after connective tissue removal and pancreas duct perfusion, and the quantity of islets obtained (including islets quantity of different diameters and total IEQ) after dissociation were not significantly different. Continuous gradient of HCA-Ficoll, compared with discontinuous gradient, resulted in significantly greater final islet quantity (55,000 IEQ vs 206,000 IEQ, P=0.000) and islet purity (58.0%-/+8.0% vs 33.5%-/+10.3%, P=0.000) and also greater number of islets with a diameter lager than 200 microm (P<0.01)., Conclusion: Continuous density gradient centrifugation can be more effective than discontinuous gradient in islet purification.

Objective: To establish an semi-automated effective method for large-scale purification of islet cells from human pancreas., Methods: Human pancreas tissue was digested with collagenase P using a semi-automated pancreas-digestion system followed by purification in a HCA-Ficoll continuous gradient using Cobe2991 cell separator. After isolation, the islet cell yield and purity was evaluated with light microscope with DTZ staining, and the islet function assessed by insulin release assay in vitro., Results: The number of the islets collected from each pancreas averaged 38 6201-/+78 219 islet equivalents (IEQ) before purification, and 231 420-/+28 054 IEQ after the purification with discontinuous gradient centrifugation. From each gram of the pancreatic tissue, 3148-/+317 IEQ were obtained with an average purity of (62.81-/+2.68) %. The purified islets responded well to high-concentration (16.7 mmol/L) glucose stimulation with a 2.53-fold increase of insulin secretion over the basal level (3.3 mmol/l, P<0.001)., Conclusion: The established semi-automated method can be applicable for large-scale purification of fully functional islet cells from human pancreas.

Syndecan-1 (CD138), a member of integral membrane heparin sulfate proteoglycans, is an essential matrix receptor for maintaining the normal morphological phenotypes. In this study, we generated a specific mouse anti-human syndecan-1 monoclonal antibody (mAb) 4B3 and identified it by competition assay with the available syndecan-1 mAb (BB4). Stained by 4B3, the expression of syndecan-1 was detected on tumor cell lines, such as 8226, U266, XG-1, XG-2, Daudi and Jurkat. The expression was also found on neuron stem cells. It was established that 4B3 mAb could inhibit XG-1 and XG-2 proliferation. The data not only determined that 4B3 mAb was a functional anti-human syndecan-1 mAb, but also indicated that syndecan-1 might be a valuable surface antigen and play an important role in regulation of tumor pathology and differentiation of neural stem cells. This novel antibody 4B3 may be value of study of tumor proliferation/survival mechanism and contributes to diagnosis and treatment of diverse diseases.

Aim: To explore the roles of H1 and H2 receptors in the locus ceruleus (LC) in the carotid baroreflex (CBR) resetting resulted from foot-shock stress., Methods: Male SD rats were divided into two groups (n=18) at random: unstressed and stressed group. The latter were subjected to unavoidable electric foot-shock twice daily for a week and each session of foot-shock lasted 2 hours. The left and right carotid sinus regions were isolated from the systemic circulation in all animals anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner in vivo. ISP-mean arterial pressure (MAP), ISP-Gain relationship curves and reflex characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CBR performance induced by stress and the effects of microinjection with histaminergic receptors antagonists into the LC on the responses of CBR to stress were examined., Results: Stress significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and obviously moved the middle part of ISP-Gain relationship curve downwards (P < 0.05), and decreased the value of the MAP range and maximum gain (P < 0.05), but increased the threshold pressure, saturation pressure, set point and ISP at maximum gain (P < 0.05). Microinjection of selective H1 or H2 receptor antagonist, chlorpheniramine (CHL, 0.5 microg/microl) or cimetidine (CIM, 1.5 microg/microl) into the LC, significantly attenuated the above-mentioned changes in CBR performance induced by stress and the alleviate effect of CIM was less remarkable than that of CHL (P < 0.05). The responses of CBR under stress to H1 or H2 receptor antagonist generally occurred 20 min after the administration and lasted approximately for 16 min. Microinjection with the same dose of CHL or CIM into the LC in the unstressed group did not change CBR performance significantly (P > 0.05). However, microinjection of CHL or CIM into the LC could not completely abolish the stress-induced changes in CBR., Conclusion: The stress results in a resetting of CBR and a decrease in reflex sensitivity. The stress-induced changes in CBR may be mediated, at least in part, by activating the brain histaminergic system. The H1 and H2 receptors in the LC, especially, Hi receptors may play an important role in the resetting of CBR under stress. The descending histaminergic pathway from the hypothalamus to LC may be involved in these effects. Moreover, the effects of stress on CBR also have other mechanisms.

The effects of monocarboxylic acid-derived Cl(-) channel blockers on cardiac depolarization-activated K(+) currents were investigated. Membrane currents in rat ventricular myocytes were recorded using the whole-cell configuration of the patch-clamp technique. 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) and niflumic acid (NFA) induced an outward current at 0 mV. Both NPPB and NFA failed to induce any current when used intracellularly or after K(+) in the bath and pipette solutions was replaced by equimolar Cs(+). Voltage pulse protocols revealed that NPPB and NFA enhanced the steady-state K(+) current but inhibited the transient outward K(+) current. Genistein, a tyrosine kinase (PTK) inhibitor, inhibited NPPB- and NFA-induced outward current. Another PTK inhibitor, lavendustin A, produced a comparable effect. In contrast, the inactive analogue of genistein, daidzein, was ineffective. Orthovanadate, a tyrosine phosphatase inhibitor, markedly slowed the deactivation of the outward current induced by NPPB and NFA. The protein kinase A (PKA) inhibitor H-89 inhibited NPPB-induced outward current at 0 mV. In contrast, the protein kinase C (PKC) inhibitor H-7 was without significant effect on the action of NPPB. Pretreatment of the myocytes with genistein or H-89 prevented the enhancing effect of NPPB. Increasing intracellular Cl(-) from 22 to 132 mm slightly reduced NPPB-induced outward current at 0 mV. These results demonstrate that the monocarboxylic acid-derived Cl(-) channel blockers NPPB and NFA enhance cardiac steady-state K(+) current, and suggest that the enhancing effect of the Cl(-) channel blockers is mediated by stimulation of PKA and PTK signalling pathways.

Aim: To investigate the roles of alpha1 and alpha2 receptors in the nucleus tractus solitarius (NTS) in the carotid baroreflex (CBR) resetting induced by the intracerebroventricular injection (ICV) of histamine (HA)., Methods: The left and right carotid sinus regions were isolated from the systemic circulation in 25 Sprague-Dawley rats anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner. ISP-mean arterial pressure (MAP) relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CBR performance induced by ICV HA and the effects of pretreatment with alpha1 or alpha2 receptor antagonist into the NTS on the responses of CBR to HA were examined., Results: ICV HA (60 micromol x L(-1) in 5 microl) significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and moved the middle part of ISP-Gain relationship curve downwards (P < 0.05), and reduced the MAP range and maximum gain (P < 0.05). The pretreatment with phenoxybenzamine (PBZ, a selective antagonist of alpha1 receptor, 3 micromol x L(-1) in 500 nl) or yohimbine (YOH, a selective antagonist of alpha2 receptor, 2.5 micromol x L(-1) in 500 nl) into the NTS could obviously intensify the above-mentioned changes in CBR performance induced by HA, but the intensive effect of PBZ was less remarkable than that of YOH (P < 0.05)., Conclusion: The intracerebroventricular administration of HA results in a rapid resetting of CBR and a decrease in reflex sensitivity, and the functions of alpha1 and alpha2 receptors in the NTS might weaken CBR resetting induced by ICV HA. Furthermore, alpha2 receptor in the NTS might play an more important role in modulating the responses of CHR to HA.

The title compounds, both [Fe(C5H5)(C15H14NO2)], crystallize with Z'=2 in the centrosymmetric space group P-1. In each compound, there is an intramolecular N-H...O=C hydrogen bond, and pairs of intermolecular O-H...O=C hydrogen bonds link the molecules into chains, parallel to [110] in the 3-hydroxy compound and parallel to [101] in the 4-hydroxy compound.

Objective To investigate the role of H(1) and H(2) receptors in the locus ceruleus (LC) in carotid sinus baroreceptor reflex (CSR) resetting induced by intracerebroventricular (i.c.v.) injection of histamine (HA). Methods The left and right carotid sinus regions were isolated from the systemic circulation in 18 male Sprague-Dawley rats anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner in vivo. ISP-mean arterial pressure (MAP) relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CSR performance induced by i.c.v. HA and the effects of pretreatment with H(1) or H(2) receptors selective antagonist, chlorpheniramine (CHL) or cimetidine (CIM) into the LC, on the responses of CSR to HA were examined. Results I.c.v. HA (100 ng in 5 mu l) significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and obviously decreased the value of the reflex parameters such as MAP range and maximum gain (P < 0.05), but increased the threshold pressure, saturation pressure and ISP at maximum gain (P < 0.05). The pretreatment with CHL (0.5 mu g in 1 mu l) or CIM (1.5 mu g in 1 mu l) into the LC could obviously attenuate the changes mentioned above in CSR performance induced by HA, but the alleviative effect of CIM was less remarkable than that of CHL (P < 0.05). Respective microinjection of CHL or CIM alone into the LC with the corresponding dose and volume did not change CSR performance significantly (P > 0.05). Conclusion Intracerebroventricular administration of HA results in a rapid resetting of CSR and a decrease in reflex sensitivity, and the responses of CSR to HA may be mediated, at least in part, by H(1) and H(2) receptors activities in the LC, especially by H(1) receptors. Moreover, the effects of the central HA on CSR might be related to a histaminergic descending pathway from the hypothalamus to LC.

Caveolae are plasmalemmal domains enriched with cholesterol, caveolins, and signaling molecules. Normally, cells that express caveolin-1 also express caveolin-2, but this has not been demonstrated in bovine aortic endothelial cells (BAECs). Here, we show that BAECs express caveolin-2, which localizes in caveolae with caveolin-1. We have cloned the bovine caveolin-2 gene and after comparison with known protein sequences (human, murine, rat, and canine) have found divergent immunogenic regions (amino acid [aa] 21 to aa 50 and aa 79 to 88), which may explain the inability to detect caveolin-2 in different cell types. We developed a bovine caveolin-2-specific antibody to examine this protein's expression and localization in BAECs. We used differential gradient centrifugations and immunoprecipitation to show that bovine caveolin-2 and caveolin-1 form a hetero-oligomer in plasma membrane caveolae. Using immunocytochemistry we show that a pool of caveolin-2 also colocalizes with the cis-Golgi in static culture, but unlike caveolin-1, this Golgi associated pool is maintained after 1 day of shear exposure. Therefore, the interaction of caveolin-2 with caveolin-1 could play an important role in caveolae biogenesis and shear stimulated mechano-signal transduction.