Involvement of Na+-HCO3- cotransporter in mediating cyclic adenosine 3',5'-monophosphate-dependent HCO3- secretion by mouse endometrial epithelium

The present study investigated the involvement of Na+-HCO3- cotransporter in mediating cAMP-stimulated HCO3- secretion across the cultured mouse endometrial epithelium using the short-circuit current (I(SC)) technique and intracellular pH measurement. Forskolin stimulated a rise in the I(SC), 55.6% and 52.1% of which could be reduced by the removal of extracellular Cl- or by eliminating the contribution of Cl- secretion by bumetanide, an inhibitor of Na+-K+-2Cl- cotransporter, respectively. More than 80% reduction in the forskolin-induced I(SC) was obtained when both Cl- and HCO3- in the bath were removed or in HCO3--free solution with bumetanide, indicating that the I(SC) depended on both Cl- and HCO3-. The presence of the Na+ channel-blocker amiloride in the apical solution did not reduce the forskolin-induced I(SC); however, the I(SC) could be abolished by removing Na+ from the bathing solution, suggesting that the Cl-- and HCO3--dependent I(SC) was also dependent on basolateral Na+. The forskolin-stimulated I(SC) could be reduced 43.6% by removal of HCO3- and 47.9% by a Na+-HCO3--cotransporter inhibitor, dihydrogen-4,4'-didsothiocyanostilbene-2,2'-disulfonic acid (H2DIDS). The inhibitory effect of H2DIDS was observed in Cl--free solution, but not when HCO3- was removed, thus confirming its effect on HCO3--dependent transport. Intracellular pH measurements demonstrated that the recovery from cellular acidification depended on the presence of both basolateral Na+ and HCO3-, further indicating the involvement of Na+-HCO3- cotransporter. Reverse transcription-polymerase chain reaction experiments confirmed the expression of Na+-HCO3- cotransporter in the mouse endometrium. The results suggest that basolaterally located Na+-HCO3- cotransporter is involved in mediating cAMP-stimulated HCO3- secretion across the mouse endometrial epithelium.

Identification of testis development and spermatogenesis-related genes in human and mouse testes using cDNA arrays

We have constructed cDNA microarrays from the human testis large insert cDNA library, containing 9216 genes, together with several housekeeping genes. The cDNA microarrays were used to identify gene expression differences between human fetal and adult testes. Of >8700 hybridized clones, 731 exhibited significant differential expression characteristics. About 7500 genes were identified when the same cDNA microarrays were used for hybridization with cDNA probes from mouse testis, with 256 genes having significant differential expression between the age of 1-4 weeks. Among these genes, 101 were identified as critically related to testis development and possibly to spermatogenesis since they were found in both human and mouse testes, and expressed differentially at different stages of testis development. Of the 101 development-related genes, 59 full-length cDNAs have been sequenced previously, while the full-length cDNAs of the other 42 genes have not been published. We have obtained 11 full-length sequences of the 42 genes and deposited them in the GenBank. The conserved testis development-related genes found in both human and mouse testes may include genes that are likely to be involved in testicular functions, especially spermatogenesis, thus providing a basis for further functional characterization of the genes in mouse models.

Androgen dependent expression of AT1 receptor and its regulation of anion secretion in rat epididymis

Our previous studies have provided solid evidence for the presence of an intrinsic angiotensin-generating system in the rat epididymis, which plays an important role in the regulation of the anion and thus fluid secretion by the epididymal epithelium. In the present study, the effect of androgen on the expression of AT(1)receptor and its subsequent regulation of anion secretion by the epididymis were investigated using Western blotting, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and in vitro electrophysiological approaches. Results from Western blotting analysis showed that the expression of AT(1)receptor protein was almost abolished by castration whereas its expression was completely restored to the control level when the castrated rats were hormonally replaced with testosterone. Efferent duct ligation, however, appeared not to affect the expression of AT(1)receptor protein by the epididymis. Results from RT-PCR showed that mRNA expression of AT(1)receptor was consistent with that observed in protein expression. Results from short-circuit current (I(SC)) showed that castration almost abolished the angiotensin II-induced I(SC). However, efferent duct ligation did not affect the angiotensin II-induced I(SC), which was completely blocked in the presence of losartan, a specific antagonist of the AT(1)receptor. These data indicate that the expression of epididymal AT(1)receptor is predominantly influenced by testicular androgens but not by testicular factors. This androgen-dependent expression of AT(1)receptor could have a role in the control of AT(1)receptor-mediated anion secretion and thus fluid secretion by the rat epididymis.

Inhibition of amiloride-sensitive Na(+) absorption by activation of CFTR in mouse endometrial epithelium

Previous studies have demonstrated amiloride-sensitive Na(+) absorption under basal conditions and cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl(-) secretion following neurohormonal stimulation in the mouse endometrial epithelium. The present study investigated the inhibition of amiloride-sensitive Na(+) absorption accompanying activation of CFTR in the mouse endometrium using the short-circuit current ( I(sc)) technique. RT-PCR demonstrated the co-expression of CFTR and epithelial Na(+) channels (ENaC) in primary cultured mouse endometrial epithelia and cultured endometrial monolayers exhibited a basal amiloride-sensitive I(sc) of 5.4 +/- 0.6 microA/cm(2). The amiloride-sensitive current fell to 3.1 +/- 0.5 microA/cm(2) after stimulation with forskolin. When the possible contribution of Na(+) absorption to the I(sc) was eliminated by amiloride (1 microM) or Na(+) replacement, the forskolin-induced I(sc) was not reduced, but rather increased significantly compared with that in the absence of amiloride or in Na(+)-containing solutions ( P < 0.02), indicating that the forskolin-induced I(sc) was mediated by Cl(-) secretion, portion of which may be masked by concurrent inhibition of basal Na(+) absorption if the contribution of Na(+) is not eliminated. When the contribution of Cl(-) to the I(sc) was eliminated by diphenylamine 2,2'-dicarboxylic acid (DPC, 2 mM) or Cl(-) replacement, forskolin now decreased, rather than increased the I(sc), demonstrating the inhibition of Na(+) absorption upon stimulation. Our data suggest an interaction between CFTR and ENaC, which may be the underlying mechanism for balancing Na(+) absorption and Cl(-) secretion across the mouse endometrial epithelium.

New insights into the mechanisms underlying hydrosalpinx fluid formation and its adverse effect on IVF outcome

The adverse effects of hydrosalpinx on the outcome of IVF have been well documented; however, the causes for impaired implantation in patients with hydrosalpinx are poorly understood. Hydrosalpinx fluid has been shown to be toxic to mouse embryos but not human embryos, and this has become a topic of intense debate. An understanding of the mechanisms underlying hydrosalpinx formation following pelvic inflammatory disease appears to be essential in elucidating the causes for reduced implantation in hydrosalpinx patients and providing more rational treatments. This review discusses the mechanisms underlying hydrosalpinx formation and its adverse effect on IVF outcome, with new insights into possible involvement of Fallopian tube epithelial transporters and ion channels, particularly the cystic fibrosis transmembrane conductance regulator (CFTR). Possible links between Chlamydia trachomatis in pelvic inflammatory disease and the subsequent CFTR-mediated events in hydrosalpinx formation leading to infertility in hydrosalpinx are proposed. The causes of reduced implantation, particularly in patients with visible hydrosalpinges shown on ultrasound scanning, are re-examined in light of these possible mechanisms.

NYD-SP6, a novel gene potentially involved in regulating testicular development/spermatogenesis

Using cDNA microarray hybridization from a human testicular cDNA library, a novel gene exhibiting 30-fold difference in expression level between adult and embryo human testes was cloned and named NYD-SP6, which was 1858 bp in length with 87% nucleotide identity with the mouse homologue sequence. The deduced protein structure of NYD-SP6 was found to contain two plant homeodomain (PHD) finger domains, believed to be involved in activating transcriptional regulation. Tissue distribution analysis using Northern blot indicated that the NYD-SP6 gene was expressed in a wide range of tissues, with a high expression level in the testis. Its expression in human and mouse testes by in situ hybridization was confined to Sertoli cells and the expression was developmentally regulated as demonstrated by cDNA microarray, in situ hybridization, and semiquantitative PCR in mouse testes. GFP/NYD-SP6 protein was predominantly localized in the nucleus of the transfected CHO cells, indicating its role in transcriptional regulation. In contrast, the N-terminal truncated NYD-SP6 (tNYD-SP6) localized in the nuclear envelope, indicating this region function as a nuclear localization signal. Further Northern blot analysis of gene expression in patients with spermatogenesis arrest revealed that NYD-SP6 was absent in one patient whose spermatogenesis was blocked at the stage of spermatocytes. Taken together, these results suggest that the putative protein of NYD-SP6 may play an important role in stimulating transcription involved in testicular development and/or spermatogenesis.

Cellular signaling mechanisms underlying pharmacological action of Bak Foong Pills on gastrointestinal secretion

Bak Foong Pills (BFP, also known as Bai Feng Wan) is an over-the-counter traditional Chinese medicine that has long been used for treating gynecological disorders and improving overall body functions, including gastrointestinal (GI) function. However, the cellular signaling mechanism underlying BFP action, especially on the GI tract, has not been elucidated. In the present study, the human colonic epithelia cell line T(84) was used as a model to investigate the effect of BFP ethanol extract on ion transport in conjunction with the short-circuit current (I(SC)) technique. The results showed that the apical addition of BFP extract produced a concentration-dependent (10-1,000 microg/ml, EC(50) = 120 microg/ml) increase in I(SC). The maximal response was observed at 500 microg/ml with an increase in I(SC) of 24.4 +/- 2.3 microA/cm(2) and apical conductance. The BFP-induced I(SC) was not observed when extracellular Cl(-) was replaced or when treated with Bumetanide (100 microM), an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter. The BFP-induced I(SC) was insensitive to the Na(+) channel blocker, amiloride, but partially inhibited by the Cl(-) channel blocker, DIDS (100 microM), and completely blocked by DPC (2 mM) or glibenclamide (1 mM) with a significant reduction in the apical conductance. The BFP-induced I(SC) could be mimicked by forskolin (10 microM), but inhibited by a pretreatment of the cells with adenylate cyclase inhibitor, MDL-12330A (10 microM). Pretreatment with EGTA (5 mM) and thapsigargin (10 microM) decreased the BFP-induced I(SC) by 10%. These results demonstrated that BFP ethanol extract exerted a stimulatory effect on gastrointestinal Cl(-) secretion by predominantly activating adenylate cyclase and apical cAMP-dependent Cl(-) channels, with minor contributions from calcium-dependent Cl(-) channels. The effect of BFP may be explored to treat GI disorders such as constipation.

Distribution and regulation of ENaC subunit and CFTR mRNA expression in murine female reproductive tract

The present study investigated the regional distribution and cyclic changes in the mRNA expression of epithelial Na+ channel (ENaC) subunit and cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated Cl- channel, in adult female mouse reproductive tract. In situ hybridization revealed that in contrast to the abundant expression of CFTR, ENaC (alpha, beta, gamma) mRNA signal was not detected throughout the estrus cycle in the ovary and oviduct. Messenger RNA for all ENaC subunits was abundantly detected in the cervical and vaginal epithelia throughout the estrus cycle but for CFTR, mRNA was found only at proestrus. In the uterine epithelium, alphaENaC mRNA was detected at diestrus but not found at any other stage, while CFTR mRNA was only detected at early estrus but not other stages. Semi-quantitative RT-PCR detected mRNA for all ENaC subunits in the uterus throughout the cycle with maximal expression at diestrus and CFTR mRNA was only found in the early stages of the cycle. The involvement of ENaC and CFTR in Na+ absorption and Cl- secretion was demonstrated in cultured endometrial epithelia using the short-circuit current technique and found to be influenced by ovarian hormones. Taken together, these data indicate a main secretory role of the ovary and oviduct and a predominantly absorptive role of the cervix and vagina. The present results also suggest an ability of the uterus to secrete and absorb at different stages of the estrus cycle. Variations in the fluid profiles may be dictated by the regional and cyclic variations in expression of ENaC and CFTR and are likely to contribute to various reproductive events in different regions of the female reproductive tract.

Suppression of ATP-induced Cl(-)secretion by enhanced expression of epithelial Na(+)channels in mouse endometrial epithelium

We have studied the effect of enhanced expression of epithelial Na(+)channels (ENaC) on the ATP-induced Cl(-)secretion in the mouse epithelium using short-circuit current (I(SC)) and RT-PCR techniques. The amiloride sensitivity of basal current (I(b)) across the cultured endometrial epithelia was found to vary with the magnitude of the I(b), the higher the I(b)the greater its sensitivity to amiloride, indicating possible elevation of ENaC. However, the magnitude of ATP-induced I(SC), previously demonstrated to be mediated by Ca(2+)-activated chloride channel (CaCC), decreased as the amiloride sensitivity of the I(b)increased, suggesting a possible inhibitory effect of elevated expression of ENaC on ATP-mediated chloride secretion. The Matrigel treatment for culturing the endometrial epithelia affected the amiloride sensitivity of the I(b)as well as the ATP-induced I(SC)reversedly. Competitive RT-PCR demonstrated that the expression of both ENaC gamma subunits and CaCC was enhanced in Matrigel-treated cultures. However, the observed reduction in the ATP-induced or CaCC-mediated I(SC)could not be explained by the CaCC expression pattern. These data suggest that inhibition of CaCC function is due to enhanced ENaC expression. Therefore, in addition to interacting with CFTR, ENaC also appears to interact with CaCC in the mouse endometrial epithelium. Physiologically the present findings indicate that enhanced expression of ENaC leads to suppression of other Cl(-)channels, such as CFTR and CaCC, thereby preconditioning the endometrium in favour of overall salt and water absorption as observed during embryo implantation.

Quantification of apoptotic DNA fragmentation in a transformed uterine epithelial cell line, HRE-H9, using capillary electrophoresis with laser-induced fluorescence detector (CE-LIF)

Apoptotic cell death of uterine epithelial cells is thought to play an important role in the onset of menstruation and the successful implantation of an embryo during early pregnancy. Abnormal apoptosis in these cells can result in dysmenorrhoea and infertility. In addition, decreased rate of epithelial apoptosis likely contributes to endometriosis. A key step in the onset of apoptosis in these cells is cleavage of the genomic DNA between nucleosomes, resulting in polynucleosomal-sized fragments of DNA. The conventional technique for assessing apoptotic DNA fragmentation uses agarose (slab) gel electrophoresis (i.e. DNA laddering). However, recent technological advances in the use of capillary electrophoresis (CE), particularly the introduction of the laser-induced fluorescence detector (LIF), has made it possible to perform DNA laddering with improved automation and much greater sensitivity. In the present study, we have further developed the CE-LIF technique by using a DNA standard curve to quantify accurately the amount of DNA in the apoptotic DNA fragments and have applied this new quantitative technique to study apoptosis in a transformed uterine epithelial cell line, the HRE-H9 cells. Apoptosis was induced in the HRE-H9 cells by serum deprivation for 5, 7 and 24 h, resulting in increased DNA fragmentation of 2.2-, 3.1- and 6.2-fold, respectively, above the 0 h or plus-serum controls. This ultrasensitive CE-LIF technique provides a novel method for accurately measuring the actions of pro- or anti-apoptotic agents or conditions on uterine epithelial cell lines.

Upregulation of cystic fibrosis transmembrane conductance regulator expression by oestrogen and Bak Foong Pill in mouse uteri

Although cystic fibrosis transmembrane conductance regulator (CFTR) has been shown to be expressed in the female reproductive tract, its functional role in the uterus is not fully understood. The present study investigated a possible physiological role of CFTR by comparing the effects of 17beta-oestradiol and Bak Foong Pill (BFP), an over-the-counter Chinese medicine used for centuries for the treatment of various gynaecological disorders, on uterus size and the expression of CFTR in the uterus of ovariectomised mice using RT-PCR. Treatment of ovariectomised mice with 17beta-oestradiol (0.2 mg/kg, p.o.) for 12 days caused a significant increase in uterine wet weight compared to vehicle. However, treatment with BFP (3 g/kg, p.o.) for the same period failed to increase uterine wet weight, indicating a lack of direct oestrogen-like activity of BFP. Analysis of CFTR mRNA expression in the harvested uteri using RT-PCR showed that both 17beta-oestradiol and BFP induced an increase in CFTR mRNA expression in mouse uteri compared to levels observed in vehicle-treated animals. These results suggest that CFTR can be upregulated by oestrogen and BFP, however, the effect exerted by BFP does not seem to be mediated by direct oestrogen-like activity. Regulation of CFTR expression by both oestrogen and gynaecological medication BFP indicates an important role of CFTR in reproductive functions.

cGMP-regulated store-operated calcium entry in human hepatoma cells

This study aimed to investigate cGMP-regulated store-operated Ca(2+)entry in human 7721 hepatoma cells. [Ca(2+)](i)was measured using Fura2/AM. After incubation of the cells with 4 microm thapsigargin, Ca(2+)entry was evoked by application of 1 mMm Ca(2+)to extracellular solution and was blocked by 3 m m Ni(2+), indicating the presence of store-operated Ca(2+)entry in human 7721 hepatoma cell line. Application of 8-Br-cGMP reduced the [Ca(2+)](i)in hepatoma 7721 cells by 80%. These data demonstrated for the first time that store-operated Ca(2+)entry pathway is present in human hepatoma cells, which is regulated by cGMP.

Effect of phenol red and steroid hormones on cystic fibrosis transmembrane conductance regulator in mouse endometrial epithelial cells

Previous studies have demonstrated that cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-mediated Cl(-)channel found in most epithelia including reproductive tract, could be regulated by various culture conditions. The present study further investigated the effect of phenol red, a pH indicator widely used in growth medium, and steroid hormones, present in the supplement fetal bovine serum (FBS), on primary cultured endometrial epithelial cells by monitoring ion channel activities using the short-circuit current technique. When compared to the results obtained with normal medium supplemented with regular FBS, the forskolin-stimulated I(SC), presumably mediated by CFTR, obtained in phenol red-free medium was significantly reduced, from 16.95+/-1.53 microA/cm(2)(control) to 9.72+/-0.89 microA/cm(2)(medium without phenol red, P< 0.05). The forskolin-activated I(SC)was further attenuated to 5.29+/-0.46 microA/cm(2)in the phenol red-free medium when supplemented with charcoal/ dextran-treated FBS where steroid hormones were removed. Our data suggest that phenol red and steroid hormones present in culture medium and FBS supplement, respectively, may somehow upregulate CFTR expression in vitro. Our study demonstrates the need for carefully choosing the culture media and supplements due to the effect of steroid hormones.

The involvement of HAb18G/CD147 in regulation of store-operated calcium entry and metastasis of human hepatoma cells

The present study examined the effect of hepatoma-associated antigen HAb18G (homologous to CD147) expression on the NO/cGMP-regulated Ca(2+) mobilization and metastatic process of human hepatoma cells. HAb18G/CD147 cDNA was transfected into human 7721 hepatoma cells to obtain a cell line stably expressing HAb18G/CD147, T7721, as demonstrated by Northern blot and immunocytochemical studies. 8-Bromo-cGMP (cGMP) inhibited the thapsigargin-induced Ca(2+) entry in a concentration-dependent manner in 7721 cells. The cGMP-induced inhibition was abolished by an inhibitor of protein kinase G, KT5823 (1 microm). However, expression of HAb18G/CD147 in T7721 cells decreased the inhibitory response to cGMP. A similar concentration-dependent inhibitory effect on the Ca(2+) entry was observed in 7721 cells in response to a NO donor, (+/-)-S-nitroso-N-acetylpenicillamine (SNAP). The inhibitory effect of SNAP on the thapsigargin-induced Ca(2+) entry was significantly reduced in HAb18G/CD147-expressing T7721 cells, indicating a role for HAb18G/CD147 in NO/cGMP-regulated Ca(2+) entry. Experiments investigating metastatic potentials demonstrated that HAb18G/CD147-expressing T7721 cells attached to the Matrigel-coated culture plates and invaded through Matrigel-coated permeable filters at the rate significantly greater than that observed in 7721 cells. Both the attachment and invasion rates could be suppressed by SNAP, and the inhibitory effect of SNAP could be reversed by NO inhibitor, N(G)-nitro-l-arginine methyl ester. The sensitivity of the attachment and invasion rates to cGMP was significantly reduced in T7721 cells as compared with 7721 cells when cells were pretreated with thapsigargin. The difference in the sensitivity between the two cells could be abolished by a Ca(2+) channel blocker, Ni(2+) (3 mm). These results suggest that HAb18G/CD147 enhances metastatic potentials in human hepatoma cells by disrupting the regulation of store-operated Ca(2+) entry by NO/cGMP.

Enhanced epithelial Na(+) channel (ENaC) activity in mouse endometrial epithelium by upregulation of gammaENaC subunit

The amiloride-sensitive epithelial Na(+) channel (ENaC), which is made of three different but homologous subunits, controls the rate of transepithelial Na(+) absorption in a variety of epithelia. The present study investigated the functional role of its subunits in regulating ENaC activity, measured as amiloride sensitive short-circuit current (I(SC)), in the mouse endometrial epithelium under different culture conditions. The treatment of the cultured epithelia with aldosterone (1 microM) or culturing cells on filters coated with concentrated Matrigel resulted in an increase in the amiloride-sensitive I(SC). Semiquantitative RT-PCR demonstrated that the expression of alpha and beta subunits was not significantly altered by these treatments, but an increase in the gamma subunit expression was observed. An 11-fold increase, induced by aldosterone, in the expression of the gamma subunit, but not in the alpha and beta subunits, was confirmed by capillary electrophoresis with laser-induced fluorescence (CE-LIF). The treatment of endometrial cells with antisense against the gammaENaC subunit abolished the aldosterone-enhanced amiloride-sensitive I(SC). The results indicated an important role of gammaENaC subunit in determining ENaC activity, and a possible role of the gammaENaC subunit in interacting with CFTR was also discussed.

Blood pressure reduction and tolerability of amlodipine versus nifedipine retard in Chinese patients with type 2 diabetes mellitus and hypertension: a randomized 1-year clinical trial

OBJECTIVE

In this 1-year clinical study, we compared the efficacy and tolerability of amlodipine and nifedipine retard in 64 Chinese Type 2 diabetic patients with hypertension.

SUBJECTS AND METHODS

There were 25 (39.1%) men and 39 (60.9%) women with mean age 60.7+/-9.9 years. Thirty-four patients were randomized to receive amlodipine 5 mg daily and 30 to receive nifedipine retard 20 mg twice daily. The daily dose of amlodipine and nifedipine retard was increased from 5 mg to 10 mg daily and 20 mg to 40 mg twice daily, respectively, if sitting BP > 140/90 mmHg.

RESULTS

Of the 64 patients, 9 dropped out early because they experienced adverse effects related to the drugs. If all treatment-related adverse effects were taken into account, 6 (19.4%) patients were from the amlodipine group and 14 (53.8%) from the nifedipine group (p = 0.011). After 1 year, 48 patients finished the study, 28 were on amlodipine and 20 were on nifedipine retard. Of the 28 patients from the amlodipine group, 11 (39.3%) required additional antihypertensive agents. Of the 20 patients from the nifedipine group, 5 (25%, p value: NS, comparing the 2 groups) required additional antihypertensive agents. Both groups showed similar and significant reduction in blood pressure from Week 6 to Week 52.

CONCLUSION

Both amlodipine and nifedipine retard are relatively safe and useful in the treatment of hypertension in Chinese Type 2 diabetic patients. Nifedipine retard, when compared to amlodipine, showed significantly more adverse effects and these may hamper long-term compliance.

Repeated intestinal perforation caused by an incomplete form of Behçet's syndrome

Behçet's disease, as initially described, is a triad of recurrent oral and genital ulcers and relapsing uveitis. The incomplete form, in which there is no ocular involvement, has been described in Japan and Korea, but this is not commonly recognized in the southern Chinese. We reported herein a rare case of repeated intestinal perforations caused by an incomplete form of Behçet's syndrome in a southern Chinese man.

Local regulation of anion secretion by pituitary adenylate cyclase-activating polypeptide in human colonic T84 cells

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a novel hypothalamic peptide, which has been shown to exert various functions in a number of tissues, including exocrine and endocrine tissues. The present study investigated the role of local PACAP in the control of anion secretion by the human colonic T84 cell. Both bioactive forms of PACAP-27 and PACAP-38 gave rise to a dose-dependent increase in the short-circuit current (I(SC)). However, there was a reversal in the order of potency observed at different concentration ranges for the two bioactive forms. PACAP-27 was greater than PACAP-38 when the peptide concentrations were below 10 n m; PACAP-38 was greater than PACAP-27 in the range of 10-80 n m. The effects of both PACAP forms were restricted to the apical aspect of the T84 cell. The I(SC)responses to both PACAP-27 and PACAP-38 were suppressed respectively by the non-selective Cl(-)channel blocker, diphenylamine-dicarboxylic acid (DPC), by the Ca(2+)dependent Cl(-)channel blocker, diisothiocyanatostilbene-disulfonic acid (DIDS) and by the Ca(2+)chelator, BAPTA-AM, indicating the involvement of Ca(2+). The expression of PACAP was demonstrated and localized specifically to the perinuclear cytoplasm of the T84 cell using immunocytochemistry, indicating its epithelial origin. Thus, the present data suggest that, in addition to the well-known cAMP-dependent pathway, PACAP may play a role in regulating colonic Cl(-)secretion via a Ca(2+)-dependent pathway, perhaps through two distinct PACAP receptor subtypes. Moreover, the regulation of anion secretion by T84 cells may be mediated by locally formed PACAP in an autocrine or paracrine fashion.

An antimicrobial peptide gene found in the male reproductive system of rats

Little is known about the innate defense mechanisms of the male reproductive tract. We cloned a 385-base pair complementary DNA and its genomic DNA named Bin1b that is exclusively expressed in the caput region of the rat epididymis and that is responsible for sperm maturation, storage, and protection. Bin1b exhibits structural characteristics and antimicrobial activity similar to that of cationic antimicrobial peptides, beta-defensins. Bin1b is maximally expressed when the rats are sexually mature and can be up-regulated by inflammation. Bin1b appears to be a natural epididymis-specific antimicrobial peptide that plays a role in reproductive tract host defense and male fertility.

The effect of videotaped or written information on Chinese gastroscopy patients' clinical outcomes

The researchers compared videotaped information with specific written information on Chinese out-patients' post-gastroscopy anxiety and satisfaction levels. We randomly allocated 30 out-patients having scheduled gastroscopy to receive videotaped or detailed written information, and assessed the effect of the information on patients' post-gastroscopy BP, pulse and self-reported anxiety and satisfaction levels. Patients receiving videotaped information had better post-gastroscopy outcomes on all measures, but the results were not statistically significant. BP and Pulse rates increased after the intervention within each group but the changes were statistically significant in the group receiving detailed written information only. A-state scores decreased in both groups after the intervention but these changes were not statistically significant. Education and age significantly influenced post-gastroscopy state anxiety scores. The researchers conclude that information may have little effect on Chinese gastroscopy patients' outcomes, irrespective of the method of providing it. Education and age may influence patients' reports of anxiety.

Adenosine triphosphate induces inhibition of Na(+) absorption in mouse endometrial epithelium: a Ca(2+)-dependent mechanism

The present study investigated the inhibitory effect of extracellular ATP on Na(+) absorption and the possible underlying mechanism in cultured mouse endometrial epithelium using the short-circuit current (I(SC)) technique. The cultured epithelia exhibited a Na(+)-dependent basal current that could be predominately blocked by the epithelial Na(+) channel (ENaC) blocker, amiloride (10 microM). Apical addition of ATP (10 microM) induced a reduction in basal I(SC). However, in the presence of amiloride or when apical Na(+) was removed, the ATP-induced reduction was abolished and an increase in the I(SC) was observed with kinetic characteristics similar to those reported previously for the ATP-induced Cl(-) secretion, indicating that ATP could induce both Cl(-) secretion and inhibition of Na(+) absorption. Further reduction in I(SC) after ATP challenge could be obtained with forskolin (10 microM), which indicates that different inhibitory mechanisms are involved. The ATP-induced inhibition of Na(+) absorption, but not that induced by forskolin, could be abolished by the P(2) receptor antagonist, reactive blue (100 microM), indicating the involvement of a P(2) receptor in mediating the ATP response. ATP and uridine 5'-diphosphate (UDP; 100 microM), a relatively selective agonist for the pyrimidinoceptor, induced separate I(SC) reduction, and distinct I(SC) increases in the presence of amiloride, regardless of the order of drug administration, indicating the involvement of two receptor populations. The ATP-induced inhibition of Na(+) absorption was mimicked by the Ca(2+) ionophore, ionomycin (1 microM), whereas the Ca(2+) chelators, EGTA and BAPTA-AM, abolished the ATP-induced, but not the forskolin-induced, inhibition of Na(+) absorption, suggesting the involvement of a Ca(2+)-dependent pathway. In the presence of the Cl(-) channel blocker, DIDS (100 microM), both inhibitory and stimulatory responses to ATP were abolished, suggesting the involvement of a Ca(2+)-activated Cl(-) channels (CaCCs) in mediating both ATP responses. The ATP-induced as well as the forskolin-induced reduction in I(SC) was not observed when Cl(-) was removed from the bathing solution, indicating that Cl(-) permeation is important for the inhibition of Na(+) absorption. The results suggest the presence of a Ca(2+)-dependent ENaC-inhibiting mechanism involving CaCC in mouse endometrial epithelial cells. Thus, extracellular nucleotides may play an important role in the fine-tuning of the uterine fluid microenvironment by regulating both Cl(-) secretion and Na(+) absorption across the endometrium.

Suppression of CFTR-mediated Cl(-) secretion by enhanced expression of epithelial Na(+) channels in mouse endometrial epithelium

The present study investigated the effect of enhanced expression of epithelial Na(+) channels (ENaC) on the cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl(-) secretion in the mouse endometrium using the short-circuit current technique. The amiloride sensitivity of the basal current of the cultured endometrial epithelia was found to vary with the magnitude of the basal current, the higher the basal current the greater its sensitivity to amiloride, indicating possible elevation of ENaC expression. However, the magnitude of the forskolin-induced Isc, previously demonstrated to be mediated by CFTR, decreased as the amiloride sensitivity of the basal current increased, suggesting a possible inhibitory effect of elevated expression of ENaC on CFTR-mediated Cl(-) secretion. The Matrigel concentration for culturing the endometrial epithelia was found to affect the amiloride sensitivity of the basal current as well as the forskolin-induced Isc in opposite directions. However, competitive RT-PCR demonstrated that the expression of both ENaC and CFTR was enhanced in Matrigel-treated culture, suggesting that the reduced forskolin-induced Isc with enhanced amiloride sensitivity was not due to a reduction in CFTR expression, but rather suppression of CFTR function by enhanced ENaC expression. In addition to the previously demonstrated inhibition of ENaC by activation of CFTR, the present results reveal possible regulation of CFTR by ENaC. The interaction between the two may be one of the underlying mechanisms for balancing Na(+) absorption and Cl(-) secretion across epithelia.