Background/Aims: Platelet-derived growth factor receptor alpha-positive (PDGFRα + ) cells function in the purinergic regulation of gastrointestinal motility, and purines are reportedly inhibitory neurotransmitters in the enteric nervous system. We explore the distribution and function of PDGFRα + cells related to purinergic inhibitory neurotransmission in human right and left colons. Methods: Human colonic segments were prepared with mucosa and submucosa intact, and the circular muscle tension and longitudinal muscle tension were recorded. Purinergic neurotransmitters were administered after recording the regular contractions.Immunohistochemistry was performed on the circular muscle layers. Intracellular recording was performed on the colonic muscular layer. SK3, P2RY1, and PDGFR-α mRNA expression was tested by quantitative real-time polymerase chain reaction (qPCR). Results: Adenosine triphosphate (ATP) treatment significantly decreased the frequency and area under the curve (AUC) of the segmental contraction in right and left colons. Beta-nicotinamide adenine dinucleotide (β-NAD) decreased the frequency in the right colon and the amplitude, frequency and AUC in the left colon. Apamin significantly increased frequency and AUC in the left colon, and after apamin pretreatment, ATP and β-NAD did not change segmental contractility. Through intracellular recordings, a resting membrane potential decrease occurred after ATP administration; however, the degree of decrease between the right and left colon was not different. PDGFRα +Conclusion Purines reduce right and left colon contractility similarly, and purinergic inhibitory neurotransmission can be regulated by PDGFRα+ cells in the human colon.

Polycystic kidney disease 2-like-1 (PKD2L1), also known as polycystin- L or TRPP3, is a non-selective cation channel that regulates intracellular calcium concentration. Calmodulin (CaM) is a calcium binding protein, consisting of N-lobe and C-lobe with two calcium binding EF-hands in each lobe. In previous study, we confirmed that CaM is associated with desensitization of PKD2L1 and that CaM Nlobe and PKD2L1 EF-hand specifically are involved. However, the CaM-binding domain (CaMBD) and its inhibitory mechanism of PKD2L1 have not been identified. In order to identify CaM-binding anchor residue of PKD2L1, single mutants of putative CaMBD and EF-hand deletion mutants were generated. The current changes of the mutants were recorded with whole-cell patch clamp. The calmidazolium (CMZ), a calmodulin inhibitor, was used under different concentrations of intracellular. Among the mutants that showed similar or higher basal currents with that of the PKD2L1 wild type, L593A showed little change in current induced by CMZ. Co-expression of L593A with CaM attenuated the inhibitory effect of PKD2L1 by CaM. In the previous study it was inferred that CaM C-lobe inhibits channels by binding to PKD2L1 at 16 nM calcium concentration and CaM N-lobe at 100 nM. Based on the results at 16 nM calcium concentration condition, this study suggests that CaM C-lobe binds to Leu- 593, which can be a CaM C-lobe anchor residue, to regulate channel activity. Taken together, our results provide a model for the regulation of PKD2L1 channel activity by CaM.

KCNQ family constitutes slowly-activating potassium channels among voltage-gated potassium channel superfamily. Recent studies suggested that KCNQ4 and 5 channels are abundantly expressed in smooth muscle cells, especially in lower urinary tract including corpus cavernosum and that both channels can exert membrane stabilizing effect in the tissues. In this article, we examined the electrophysiological characteristics of overexpressed KCNQ4, 5 channels in HEK293 cells with recently developed KCNQ-specific agonist. With submicromolar EC50 , the drug not only increased the open probability of KCNQ4 channel but also increased slope conductance of the channel. The overall effect of the drug in whole-cell configuration was to increase maximal whole-cell conductance, to prolongate the activation process, and left-shift of the activation curve. The agonistic action of the drug, however, was highly attenuated by the co-expression of one of the βancillary subunits of KCNQ family, KCNE4. Strong in vitro interactions between KCNQ4, 5 and KCNE4 were found through Foster Resonance Energy Transfer and co-immunoprecipitation. Although the expression levels of both KCNQ4 and KCNE4 are high in mesenteric arterial smooth muscle cells, we found that 1 μM of the agonist was sufficient to almost completely relax phenylephrine-induced contraction of the muscle strip. Significant expression of KCNQ4 and KCNE4 in corpus cavernosum together with high tonic contractility of the tissue grants highly promising relaxational effect of the KCNQspecific agonist in the tissue.

Polycystic kidney disease 2-like-1 (PKD2L1), also known as polycystin- L or TRPP3, is a non-selective cation channel that regulates intracellular calcium concentration. Calmodulin (CaM) is a calcium binding protein, consisting of N-lobe and C-lobe with two calcium binding EF-hands in each lobe. In previous study, we confirmed that CaM is associated with desensitization of PKD2L1 and that CaM Nlobe and PKD2L1 EF-hand specifically are involved. However, the CaM-binding domain (CaMBD) and its inhibitory mechanism of PKD2L1 have not been identified. In order to identify CaM-binding anchor residue of PKD2L1, single mutants of putative CaMBD and EF-hand deletion mutants were generated. The current changes of the mutants were recorded with whole-cell patch clamp. The calmidazolium (CMZ), a calmodulin inhibitor, was used under different concentrations of intracellular. Among the mutants that showed similar or higher basal currents with that of the PKD2L1 wild type, L593A showed little change in current induced by CMZ. Co-expression of L593A with CaM attenuated the inhibitory effect of PKD2L1 by CaM. In the previous study it was inferred that CaM C-lobe inhibits channels by binding to PKD2L1 at 16 nM calcium concentration and CaM N-lobe at 100 nM. Based on the results at 16 nM calcium concentration condition, this study suggests that CaM C-lobe binds to Leu- 593, which can be a CaM C-lobe anchor residue, to regulate channel activity. Taken together, our results provide a model for the regulation of PKD2L1 channel activity by CaM.

KCNQ family constitutes slowly-activating potassium channels among voltage-gated potassium channel superfamily. Recent studies suggested that KCNQ4 and 5 channels are abundantly expressed in smooth muscle cells, especially in lower urinary tract including corpus cavernosum and that both channels can exert membrane stabilizing effect in the tissues. In this article, we examined the electrophysiological characteristics of overexpressed KCNQ4, 5 channels in HEK293 cells with recently developed KCNQ-specific agonist. With submicromolar EC50 , the drug not only increased the open probability of KCNQ4 channel but also increased slope conductance of the channel. The overall effect of the drug in whole-cell configuration was to increase maximal whole-cell conductance, to prolongate the activation process, and left-shift of the activation curve. The agonistic action of the drug, however, was highly attenuated by the co-expression of one of the βancillary subunits of KCNQ family, KCNE4. Strong in vitro interactions between KCNQ4, 5 and KCNE4 were found through Foster Resonance Energy Transfer and co-immunoprecipitation. Although the expression levels of both KCNQ4 and KCNE4 are high in mesenteric arterial smooth muscle cells, we found that 1 μM of the agonist was sufficient to almost completely relax phenylephrine-induced contraction of the muscle strip. Significant expression of KCNQ4 and KCNE4 in corpus cavernosum together with high tonic contractility of the tissue grants highly promising relaxational effect of the KCNQspecific agonist in the tissue.

Polycystic kidney disease 2-like-1 (PKD2L1), polycystin-L or transient receptor potential polycystin 3 (TRPP3) is a TRP superfamily member. It is a calcium-permeable non-selective cation channel that regulates intracellular calcium concentration and thereby calcium signaling. Although the calmodulin (CaM) inhibitor, calmidazolium, is an activator of the PKD2L1 channel, the activating mechanism remains unclear. The purpose of this study is to clarify whether CaM takes part in the regulation of the PKD2L1 channel, and if so, how. With patch clamp techniques, we observed the current amplitudes of PKD2L1 significantly reduced when coexpressed with CaM and CaMΔN. This result suggests that the N-lobe of CaM carries a more crucial role in regulating PKD2L1 and guides us into our next question on the different functions of two lobes of CaM. We also identified the predicted CaM binding site, and generated deletion and truncation mutants. The mutants showed significant reduction in currents losing PKD2L1 current-voltage curve, suggesting that the C-terminal region from 590 to 600 is crucial for maintaining the functionality of the PKD2L1 channel. With PKD2L1608Stop mutant showing increased current amplitudes, we further examined the functional importance of EF-hand domain. Along with co-expression of CaM, ΔEF-hand mutant also showed significant changes in current amplitudes and potentiation time. Our findings suggest that there is a constitutive inhibition of EF-hand and binding of CaM C-lobe on the channel in low calcium concentration. At higher calcium concentration, calcium ions occupy the N-lobe as well as the EF-hand domain, allowing the two to compete to bind to the channel.
Binding Sites ; Calcium ; Calcium Signaling ; Calmodulin ; Ion Channels ; Ions ; Patch-Clamp Techniques ; Polycystic Kidney Diseases ; Transient Receptor Potential Channels

The transient receptor potential canonical (TRPC) 5 channel, known as a nonselective cation channel, has a crucial role in calcium influx. TRPC5 has been reported to be activated by muscarinic receptor activation and extracellular pH change and inhibited by the protein kinase C pathway. Recent studies have also suggested that TRPC5 is extracellularly activated by englerin A (EA), but the mechanism remains unclear. The purpose of this study is to identify the EA-interaction sites in TRPC5 and thereby clarify the mechanism of TRPC5 activation. TRPC5 channels are over-expressed in human embryonic kidney (HEK293) cells. TRPC5 mutants were generated by site-directed mutagenesis. The whole-cell patch-clamp configuration was used to record TRPC5 currents. Western analysis was also performed to observe the expression of TRPC5 mutants. To identify the EA-interaction site in TRPC5, we first generated pore mutants. When screening the mutants with EA, we observed the EA-induced current increases of TRPC5 abolished in K554N, H594N, and E598Q mutants. The current increases of other mutants were reduced in different levels. We also examined the functional intactness of the mutants that had no effect by EA with TRPC5 agonists, such as carbachol or GTPγS. Our results suggest that the three residues, Lys-554, His-594, and Glu-598, in TRPC5 might be responsible for direct interaction with EA, inducing the channel activation. We also suggest that although other pore residues are not critical, they could partly contribute to the EA-induced channel activation.
Calcium ; Carbachol ; Humans ; Hydrogen-Ion Concentration ; Ion Channels ; Kidney ; Mass Screening ; Mutagenesis, Site-Directed ; Mutant Proteins ; Protein Kinase C ; Receptors, Muscarinic

PURPOSE: The current study is aimed to assess whether a longer duration of 5α-reductase inhibitor (5α-RI) exposure was associated with higher rate of permanent erectile dysfunction (ED) in a rat model. MATERIALS AND METHODS: Male Sprague-Dawley rats (n=76) were assigned to five groups: (i) normal control group; (ii) dutasteride (0.5 mg/rat/d) for 4-weeks group; (iii) dutasteride for 4-weeks plus 2-weeks of resting group; (iv) dutasteride for 8-weeks group; and (v) dutasteride for 8-weeks plus 2-weeks of resting group. In vivo erectile responses to electrical stimulation, and changes of fibrotic factors and smooth muscle/collagen contents in the corpus cavernosum were evaluated in each group. RESULTS: Dutasteride administration for 4 and 8 weeks significantly decreased erectile parameters compared with the control group. Reduced erectile responses were recovered during 2 weeks of drug-free time in the 4-week treatment group, but were not in the 8-week group. Protein levels of fibrosis-related factors transforming growth factor (TGF)-β1, TGF-β2, and p-Smad/Smad (Smad 2/3) in the corpus cavernosum showed no significant change after 4 weeks of dutasteride oral administration, but were enhanced after 8 weeks. Dutasteride markedly decreased smooth muscle content and increased collagen after 4 and 8 weeks of use, but no nuclear size changes; however, neither group showed significant improvement in the smooth muscle to collagen ratio after the rest period. CONCLUSIONS: Our study showed that recovery from ED depended on the duration of medication, and administration of dutasteride for more than 8-weeks in rats could result in irreversible ED even after discontinuation of medication.
5-alpha Reductase Inhibitors ; Administration, Oral ; Animals ; Collagen ; Dutasteride ; Electric Stimulation ; Erectile Dysfunction ; Finasteride ; Humans ; Male ; Models, Animal ; Muscle, Smooth ; Oxidoreductases ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factors

PURPOSE: This study analyzed the perception and importance of country-of-origin labeling at restaurants in 500 college students in Jeju surveyed from April 15 to May 5, 2016 with the aim of providing basic data. A total of 465 questionnaires out of 500 were used as base data for this study. METHODS: The data were analyzed using descriptive analysis, χ2-test, and t-test using the SPSS Win program (version 21.0). RESULTS: Regarding food safety-related dietary behaviors, average score was 3.65 points (out of 5), and ‘put the food in a refrigerator or freezer immediately (4.07)’ showed the highest score, whereas ‘cool rapidly hot food prior to putting it in the refrigerator (3.08)’ showed the lowest score. Regarding the awareness of country-of-origin labeling at restaurants, 67.5% of subjects were aware of it. With regard to dietary behavior of food safety, the high group showed a higher score than the low group (p < 0.001). Regarding reliability of the system, 4.9% of subjects indicated ‘very reliable’ and 45.4% ‘somewhat reliable’. For perception of subject's country-of-origin labeling, the average score was 3.77 (out of 5). Regarding checking country-of-origin labeling at restaurants, 68.0% of subjects checked country-of-origin labeling, and the high group in the safety-related dietary behavior score ranking showed a higher rate (79.3%) than the low group (57.1%) (p < 0.001). With regard to importance by item, 'honest country-of-origin labeling of restaurants' showed the highest score at 4.27 (out of 5). CONCLUSION: It is necessary to provide continuing education for college students in order to enhance their perception of country-of-origin labeling at restaurants. Moreover, a systematic and appropriate support and control system by the government and local government needs to be developed in order to improve country-of-origin labeling at restaurants.
Education, Continuing ; Food Safety ; Humans ; Local Government ; Restaurants*

PURPOSE: The purpose of this study is to evaluate the role of regular postoperative surveillance to improve the prognosis of patients with breast cancer after curative surgery. MATERIALS AND METHODS: We retrospectively analyzed the medical records of 4,119 patients who received curative surgery for breast cancer at Samsung Medical Center between January 2000 and September 2008. Patients were divided into two groups (group I, regular postoperative surveillance; group II, control group) according to their post-therapy follow-up status for the first 5 years after surgery. RESULTS: Among the 3,770 patients selected for inclusion, groups I and II contained 3,300 (87%) and 470 (13%) patients, respectively. The recurrence rates at 5 years for groups I and II were 10.6% and 16.4%, respectively (hazard ratio, 0.85; 95% confidence interval [CI], 0.67 to 1.09; p=0.197). The 10-year mortality cumulative rates were 8.8% for group I and 25.4% for group II (hazard ratio, 0.28; 95% CI, 0.22 to 0.35; p < 0.001). In multivariate analysis for recurrence-free survival (RFS), age over 40 years (p < 0.001), histologic grade 1 (p < 0.001), and pathologic stage I (p < 0.001) were associated with longer RFS but not with follow-up status. Multivariate analysis for overall survival (OS) revealed that patients in group I showed significantly improved OS (hazard ratio, 0.29; 95% CI, 0.23 to 0.37; p < 0.001). Additionally, age over 40 years, histologic grade I, and pathologic stage I were independent prognostic factors for OS. CONCLUSION: Regular follow-up for patients with breast cancer after primary surgery resulted in clinically significant improvements in patient OS.
Breast Neoplasms* ; Breast* ; Epidemiology ; Follow-Up Studies ; Humans ; Medical Records ; Mortality ; Multivariate Analysis ; Prognosis ; Recurrence ; Retrospective Studies