The role of resistin on metabolic syndrome-induced erectile dysfunction and the possible therapeutic effect of Boldine.

BACKGROUND: Resistin is known as a potential mediator of obesity-associated insulin resistance. The high resistin level disrupts nitric oxide (NO)-mediated relaxation which is also important in erectile function. An antioxidant alkaloid, Boldine, is known as anti-diabetic and protects endothelial functions. OBJECTIVES: We aimed to investigate resistin expression in penile tissue in the presence of insulin resistance (IR) and the effect of Boldine treatment on erectile functions in the metabolic syndrome (MetS) rat model. MATERIALS AND METHODS: Wistar rats were randomly divided into three groups: Control, MetS, and boldine treated MetS group. MetS parameters were assessed by serum triglycerides (TG), uric acid (UA), glucose, insulin levels, HOMA index, and waist circumference (WC)/tibia length (TL) ratio. To evaluate erectile functions, intracavernous pressure (ICP)/mean arterial pressure (MAP) ratio was performed during cavernous nerve stimulation. Protein expressions of resistin, endothelial nitric oxide synthase (eNOS), p(S1177) eNOS, and insulin receptor-ß were evaluated by Western blotting. RESULTS: TG, glucose, insulin levels, weight, WC/TL ratio, HOMA index and resistin expression in penile tissue were significantly increased and ICP/MAP values, and p (S1177) eNOS expression in penile tissue were decreased in MetS group. Boldine treatment enhanced ICP/MAP values, insulin receptor-ß and p(S1177) eNOS expressions compared with the MetS group. DISCUSSION AND CONCLUSION: MetS caused a deterioration in erectile function accompanied by an increase in resistin expression and a reduction in eNOS enzyme activation in the rat penile tissues. Boldine treatment resulted in an improvement in erectile function, independent of resistin expression.

A New Application Route of Nitrofurantoin: Preparation and Characterization of Novel Transdermal Formulations.

OBJECTIVES: Nitrofurantoin is widely used in the prophylaxis of urinary-tract infections. The aim of this study was to develop and characterize innovative transdermal formulations of nitrofurantoin, to increase the patient compliance and decrease the adverse effects such as nausea and vomiting which limit the drug use in long-term. METHODS: Nitrofurantoin loaded microemulsion, gel (hydrogel, lipogel and DMSO gel) and film formulations were prepared and characterized via several parameters. Ex-vivo drug permeation studies were performed to determine the amount of drug permeated through the rat skin. In in-vivo studies, in order to detect nitrofurantoin in urine, the selected formulations were applied to male Wistar rats transdermally. Also, skin irritation tests (transepidermal water loss and erythema) were performed. RESULTS: All nitrofurantoin loaded formulations were prepared successfully and were stable at +4°C for 3 months. 13%, 16%, 32.5%, 36.5% and 39% of drugs permeated through the rat skin in the 168th hour for hydrogel, lipogel, film, microemulsion and DMSO gel, respectively. Only with film and DMSO gel formulations, nitrofurantoin was detected in urine. Transepidermal water loss was increased compared to basal level in film type formulations (p<0.05). However, in erythema experiments there was no difference (p>0.05). CONCLUSION: There is no approved transdermal formulation of nitrofurantion on the market. Therefore, the prepared film formulations could be an alternative due to their high penetration through the rat skin, the presence of nitrofurantoin in urine and because they cause no irritation on the skin.

Effects of resveratrol on the alterations of cavernosal eNOS and LOX-1 expression in the hypercholesterolemic condition: a preliminary study.

BACKGROUND/AIM: The aim of this study was to determine the effects of resveratrol on the alterations of cavernosal eNOS and LOX-1 mRNA expression in the hypercholesterolemic condition. MATERIALS AND METHODS: Twenty-one New Zealand white male rabbits were separated into three groups. Rabbits were fed with a normal dietary intake for the control group and a 2% cholesterol diet for the hypercholesterolemia and resveratrol groups for 6 weeks. Resveratrol 4 mg/kg daily was administered for the resveratrol group. Cavernosal LOX-1 and eNOS mRNA expressions were determined with real-time RT-PCR in all groups. The statistical analysis was performed with the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: We found no difference between mean LOX-1 mRNA expression levels in the three groups. Lower mean eNOS mRNA expression level was determined in the hypercholesterolemia group when compared with the control group (P = 0.011). Mean eNOS mRNA expression level in the resveratrol group was similar to that in the control group but significantly higher than that in the hypercholesterolemia group (P < 0.001). CONCLUSION: This preliminary study demonstrates the beneficial effects of resveratrol on cavernosal eNOS expression. The presence of cavernosal LOX-1 expression was also shown for the first time. Resveratrol may be an alternative option in hypercholesterolemic erectile dysfunction with further studies supporting its beneficial effects on the corpus cavernosum.

Resveratrol Protects and Restores Endothelium-Dependent Relaxation in Hypercholesterolemic Rabbit Corpus Cavernosum.

INTRODUCTION: Oxidative stress dependent-decrease in nitric oxide (NO) bioavailability plays an integral role in hypercholesterolemia-induced erectile dysfunction (ED). Resveratrol has been demonstrated to exert beneficial effects against oxidative stress and improve NO bioavailability. AIM: The protective and restorative potentials of resveratrol on endothelium-dependent relaxations were evaluated in hypercholesterolemic rabbit corpus cavernosum (CC). METHODS: Hypercholesterolemia was induced by administering 2% cholesterol diet (CD) (w/w) to the rabbits for 6 weeks. Two different protocols were applied to test the effects of resveratrol on hypercholesterolemia-induced ED. In Protocol-1 (P1), resveratrol was administrated to the rabbits simultaneously with CD in order to evaluate the protective effect, and for Protocol-2 (P2), resveratrol was administrated for 6 weeks after termination of CD in order to evaluate the restorative effect. MAIN OUTCOME MEASURES: Endothelium-dependent relaxations of CC were evaluated by using organ bath studies. In order to elucidate the possible molecular mechanisms, we measured endothelial NO synthase (eNOS) and phosphovasodilator-stimulated phosphoprotein (VASP) expressions and activations, NADPH oxidase, superoxide dismutase (SOD), and catalase (CAT) and glutathione peroxidase (GPx) activity in cavernosal tissues obtained at the end of the study. RESULTS: Resveratrol showed an improvement in the endothelium-dependent relaxation responses in vitro. We demonstrated significantly increased activatory-phosphorylation (p[S1177]-eNOS) and activated phosphovasodilator-stimulated phosphoprotein (phospho-VASP) levels, but reduced phosphorylation (p[T495]-eNOS) of eNOS and NADPH oxidase activity in the resveratrol-administered HC animals compared with hypercholesterolemic control rabbits in the P1. In the P2, resveratrol exhibited an improvement in endothelium-dependent relaxation responses and more pronounced effects on eNOS activation. CONCLUSION: Resveratrol administration, either simultaneously with HC diet or after HC, caused an improvement in the endothelium-dependent relaxation responses in the CC, suggesting its potential in both protective and restorative purposes in hypercholesterolemic rabbit CC.

The Role of Rac1 on Carbachol-induced Contractile Activity in Detrusor Smooth Muscle from Streptozotocin-induced Diabetic Rats.

This study was designed to determine the role of the small GTPase Rac1 on carbachol-induced contractile activity in detrusor smooth muscle using small inhibitor NSC 23766 in diabetic rats. Rac1 expression in bladder tissue was also evaluated. In the streptozotocin (STZ)-induced diabetic rat model, three study groups were composed of control, diabetic and insulin-treated diabetic subjects. The detrusor muscle strips were suspended in organ baths at the end of 8-12 weeks after STZ injection. Carbachol (CCh) (10(-9) -10(-4) M) concentration-response curves were obtained both in the absence and in the presence of Rac1 inhibitor NSC 23766 (0.1, 1 and 10 µM). Diabetes-related histopathological changes and Rac1 expressions were assessed by haematoxylin and eosin staining and immunohistochemical staining, respectively. CCh caused dose-dependent contractile responses in all the study groups. Rac1 inhibitor NSC 23766 inhibited CCh-induced contractile responses in all groups, but this inhibition seen in both diabetes groups was greater than in the control group. Histological examination revealed an increased bladder wall thickness both in the diabetes and in the insulin-treated diabetes groups compared to the control group. In immunohistochemical staining, expression of Rac1 was observed to be increased in all layers of bladder in both diabetic groups compared to the control group. In the diabetic bladders, increased expression of Rac1 and considerable inhibition of CCh-induced responses in the presence of NSC 23766 compared to those of the control group may indicate a specific role of Rac1 in diabetes-related bladder dysfunction, especially associated with cholinergic mediated detrusor overactivity.

Intra-amniotic administration of urinary trypsin inhibitor preserves intestinal contractility in meconium induced intestinal damage in chick embryos with gastroschisis.

BACKGROUND: Intestinal damage causes intestinal dysmotility in gastroschisis. Urinary trypsin inhibitor (UTI) has been shown to prevent intestinal damage in chick embryos with gastroschisis. The effect of intra-amniotic administration of UTI on intestinal motility in gastroschisis has not been investigated. METHODS: Five-day-old fertilized chick embryos were used. Gastroschisis was created through the amniotic cavity without opening the allantoic cavity. There were six groups; control, gastroschisis only, gastroschisis plus meconium and three treatment groups. In the treatment groups, 100 IU/mL, 200 IU/mL and 400 IU/mL UTI were instilled into the amniotic cavity of the gastroschisis plus meconium embryos, respectively. Serosal thickness of the intestines in each group was measured histopathologically. The contractions of the intestines were evaluated by in vitro organ bath technique and the responses were expressed as maximal contraction induced by acetylcholine. RESULTS: The serosal thickness was significantly increased in the gastroschisis plus meconium, 100 IU/mL, 200 IU/mL UTI groups compared to control and gastroschisis only groups. The serosal thickness of the 400 IU/mL UTI group was similar to control and gastroschisis only groups. Contractility of the intestines was diminished in the gastroschisis plus meconium, 100 IU/mL and 200 IU/mL UTI groups. There was no significant difference regarding contractility among control, gastroschisis only and 400 IU/mL UTI groups. CONCLUSION: Intra-amniotic administration of UTI preserves intestinal contractility in chick embryos with gastroschisis. However, preservation of intestinal dysmotility by using UTI in the human gastroschisis cases needs further experimental and clinical trials.

Rational pharmacotherapy training for fourth-year medical students.

OBJECTIVES: In this study we aimed to evaluate the impact of Rational Pharmacotherapy (RPT) course program, reinforced by video footages, on the rational pharmacotherapy skills of the students. MATERIALS AND METHODS: RPT course program has been conducted in Dokuz Eylul University School of Medicine since 2008/9. The course has been organised in accordance with World Health Organisation (WHO) Good Prescribing Guide. The aim of the course was to improve the problem solving skills (methodology for selection of the (p)ersonel-drug, prescription writing and informing patient about his illness and drugs) and communication skills of students. The impact of the course has been measured by pre/post-test design by an objective structured clinical examination (OSCE). In academic year 2010/11, to further improve OSCE score of the students we added doctor-patient communication video footages to the RPT course programme. During training, the students were asked to evaluate the doctor-patient communication and prescription on two video footages using a checklist followed by group discussions. RESULTS: Total post-test OSCE score was significantly higher for 2010/11 academic year students (n = 147) than it was for 2009/10 year students (n = 131). The 2010/11 academic year students performed significantly better than the 2009/10 academic year students on four steps of OSCE. These steps were "defining the patient's problem", "specifying the therapeutic objective", "specifying the non-pharmacological treatment" and "choosing a (drug) treatment, taking all relevant patient characteristics into account". CONCLUSIONS: The present study demonstrated that the implementation of video footages and group discussions to WHO/Good Prescribing Method improved the fourth-year medical students' performance in rational pharmacotherapy skills.

A study on the protective activity of kefir against gastric ulcer.

BACKGROUND/AIMS: The effect of kefir on peptic ulcer disease was evaluated in an experimental model, with non-steroid anti-inflammatory drugs, together with the determination of gastric mucus secretion by quantitative digital histochemistry. MATERIALS AND METHODS: The experimental group included 28 male albino Wistar rats. After a diet with standard rat bait for 7 days, 14 rats were fed with kefir for 7 days while the others were kept on the same diet. At the 14th day, indomethacin was injected to 7 of the rats fed on kefir and to 7 of the rats on standard rat bait. All the rats were sacrificed after 4 hours. Gastric erosion and ulceration were scored histopathologically. Mucosal mucus was quantified by image analysis, and periodic acid-Schiff stained area percentage was determined. RESULTS: Erosion and ulceration were identified only in cases that received indomethacin. In the cases on kefir, erosion was identified in 6 cases (86%) and ulceration in 1 case. Rats fed on standard diet had erosion in 4 cases (57%) and ulceration in 3 (43%), but the difference was statistically insignificant (Mann-Whitney test, p=0.25). The stained area percentage for gastric mucus was not different between the four groups (Kruskal-Wallis test, p=0.313). CONCLUSIONS: These findings suggest that kefir does not change gastric mucus secretion. Although statistically insignificant, as there were more cases with ulceration in cases on the rat diet, kefir might have a beneficial effect on peptic ulcer disease induced by non-steroid anti-inflammatory drug. This requires further evaluation in larger series.

Could decitabine treatment impair memory functions in humans?

The role of epigenetic mechanisms in cognitive functions and neurological/psychiatric disorders has been studied in a number of studies recently. One of these mechanisms is DNA methylation, for which DNA methyltransferases (DNMT) are responsible. Decitabine, or 5-aza-2'-deoxycytidine, is a cytosine-analog DNMT inhibitor and is used in the treatment of certain myelodysplastic syndromes (MDS) subsets. Several studies address the role of DNA methylation and negative effects of decitabine on memory formation and consolidation in animals. We, therefore, hypothesize that standard decitabine treatment for MDS in patients without dementia might cause learning and memory deficits. A clinical trial is proposed to test the hypothesis which could support the role of DNA methylation in cognitive abilities of humans.

Investigation of the neural target level of hyperthyroidism in premature ejaculation in a rat model of pharmacologically induced ejaculation.

INTRODUCTION: Association between hyperthyroidism and premature ejaculation was demonstrated in clinical studies. AIM: The aim of this study is to determine the target level of changes on ejaculatory physiology under hyperthyroid states. METHODS: p-Chloroamphetamine (PCA)-induced pharmacologic ejaculation model with 24 male Wistar rats was used in the study. Subcutaneous injection of L-thyroxine for 14 days was performed to induce hyperthyroidism. At the end of the injection period, thyroid hormone status was evaluated by serum thyroid-stimulating hormone measurements in all rats. At the beginning of the operations, complete spinal transections (tx) at the T8-T9 level were performed to half of the L-thyroxine-injected and control group rats. Thus, experimental groups were constructed as follows: Group 1--control-spinal intact (n=6), group 2-control-spinal tx (n=6), group 3-hyperthyroid-spinal intact (n=6), and group 4-hyperthyroid-spinal tx (n=6). Ejaculatory responses were recorded before and 30 minutes after intraperitoneal administration of 5 mg/kg PCA. MAIN OUTCOME MEASURES: During the operations, seminal vesicle (SV) catheterization and bulbospongiosus (BS) muscle dissections were performed in all rats to demonstrate SV pressure (SVP) BS electromyographic (EMG) activity changes. RESULTS: Following PCA administration SVP tonic amplitude, SV phasic contraction (SVPC) frequency, SVPC maximal amplitude, and BS EMG area under curve values were higher in hyperthyroid intact rats than in control intact rats. The time interval between PCA administration and first ejaculation of hyperthyroid intact rats were significantly shorter than control intact rats (261 ± 7.30 seconds vs. 426 ± 49.6 seconds, P=0.008). All of the changes in the ejaculatory parameters that were induced by hyperthyroidism were completely resolved after spinal transections at the T8-T9 level in group 4. CONCLUSION: In this study, we confirmed the recent data that hyperthyroidism affects both the emission and expulsion phases of ejaculation. The changes that were induced by hyperthyroidism on ejaculatory physiology probably take place in the supraspinal centers above T8 level.

Acute effects of hypercholesterolemic diet on erectile responses in rats.

OBJECTIVE: The aim of this study was to evaluate the acute effects of a high cholesterol diet (HCD) on erectile and endothelial functions in Sprague-Dawley rats. MATERIALS AND METHODS: Sprague-Dawley rats were divided into 2 groups as control and HCD groups. The control group was fed on a normal diet and the hypercholesterolemia group was fed a 1% cholesterol-enriched diet daily for 2 weeks. Total cholesterol levels were measured at the end of 2 weeks in both groups. To examine the effect of HCD on erectile function, electric cavernous nerve stimulation (CNS) at 20 Hz with a pulse duration of 1 ms for 1 min at 5 V was performed. During CNS, we measured intracavernous pressure (ICP), mean arterial pressure (MAP), detumescence time and area under the curve (AUC). To evaluate the endothelial responses, acetylcholine (Ach) was applied cumulatively (1 nM to 1 microM) to thoracic aorta tissues contracted with 60 mM KCl. RESULTS: In the HCD group total cholesterol levels were significantly higher than in the control group (148.1 +/- 18.9 vs. 55.7 +/- 8.1 mg/dl, p = 0.002). The detumescence time was significantly decreased after HCD compared to the control diet (19.3 +/- 3.6 vs. 78.6 +/- 12.8 s, p < 0.001). The decreases in the HCD group were also significant in terms of ICP (53.4 +/- 4.5 vs. 35.6 +/- 5.5 mm Hg; p < 0.05), ICP/MAP (55.9 +/- 3.9 vs. 38.2 +/- 5.2%; p < 0.05) and AUC (1,404 +/- 197.1 vs. 2,250 +/- 253.7, p < 0.05) values. There were no significant changes in maximum relaxation responses of the thoracic aorta to Ach. CONCLUSION: These results suggest that erectile functions were significantly damaged early in HCD rats. However, endothelial functions, evaluated in the thoracic aorta, were not affected simultaneously with erectile functions in rats fed a low concentration of HCD.

Contractility of diabetic human corpus cavernosum smooth muscle in response to serotonin mediated via Rho-kinase.

BACKGROUND/AIMS: Serotonin (5-hydroxytryptamine, 5-HT)-induced contraction and the involvement of RhoA/Rho-kinase pathway in the 5-HT-induced contraction was investigated isometrically in vitro in both diabetic and nondiabetic human corpus cavernosum (HCC) tissues. METHODS: HCC tissues were obtained from 12 patients. The response to 5-HT (10(-9) to 10(-5) mol/l) was studied in isolated HCC tissues in the absence and in the presence of a Rho-kinase inhibitor (Y-27632). RESULTS: Preincubation with Y-27632 attenuated maximum contractions induced by 5-HT in tissues of both nondiabetics and diabetics. When diabetic and nondiabetic groups were compared, no significant difference was seen in 5-HT-induced contraction alone, but in the presence of Y-27632, 5-HT-induced contraction was significantly higher in the diabetic group. CONCLUSION: These results suggest that the Rho-kinase-mediated pathway plays an important role for 5-HT-induced contraction in diabetic corpus cavernosum tissues.

Does adenosine A(1) receptor stimulation causes QRS prolongation by blocking beta adrenergic receptors in amitriptyline poisoning?

AIMS: To investigate the role of beta receptor blockade via adenosine A(1) receptor stimulation on amitriptyline-induced QRS prolongation. METHODS: Isolated rat hearts were randomized into three groups (n=8 for each group). After pretreatment with 5% dextrose (control) or DPCPX (8-cyclopentyl-1,3-dipropylxanthine), or propranolol + DPCPX, amitriptyline infusion was given to all groups. Intact beta adrenergic receptor response was verified with a bolus dose of isoproteranol (3 x 10(-5)M). RESULTS: Amitriptyline (5.5 x 10(-5)M) infusion following pretreatment with 5% dextrose or 10(-4)M DPCPX prolonged QRS by 40-110% and 30-75%, respectively. After the beta receptor blockade with 10(-2)M propranolol bolus, amitriptyline infusion following pretreatment with DPCPX prolonged QRS by 40-130%. Amitriptyline infusion following pretreatment with DPCPX (10(-4)M) shortened the QRS at 40, 50 and 60 min significantly when compared to propranolol+DPCPX group (168.8+/-4.9%, p<0.05; 170.8+/-6.9%, p<0.01; 174.0+/-6.9%, p<0.01, respectively). Amitriptyline infusion following pretreatment with 5% dextrose prolonged QRS duration significantly at 50th minutes (209.5+/-6.1%, p<0.05) compared to DPCPX pretreatment group. CONCLUSION: DPCPX pretreatment shortened amitriptyline-induced QRS prolongation. Beta adrenergic receptor blockade enhanced QRS prolongation shortened by DPCPX pretreatment. Adenosine A(1) receptor stimulation related to beta adrenergic receptor blockade may play a role in amitriptyline-induced QRS prolongation in isolated rat hearts.

Restraint stress impairs erectile responses in rats.

It has been established that various forms of physical and psychological stress reduce sexual functions. However, there is no study yet evaluating the functional changes over cavernosal pressure in rats exposed to restraint stress. In this study, we aimed to investigate the convenience of the restraint stress model that may be used to determine the disruptive effects of stress on erectile function. Sprague Dawley rats were randomized into two groups as control (n = 7) and stress (n = 7) groups. In the stress group, rats were placed for 60 minutes in a cylindrical plastic tube with holes for fresh air supply (restraint stress). Following the stress application, several parameters for erectile responses were evaluated immediately. The control animals were maintained at room temperature without any procedure until the measurement. During the electrical stimulation of cavernous nerve, we measured the intracavernous pressure (ICP), the ratio of ICP to the mean arterial pressure (MAP), and detumescence time. There were significant decreases in ICP (24.4 +/- 4.1 vs 53.4 +/- 4.5 mmHg, p < 0.01), ICP/MAP (34.4 +/- 7.8% vs 55.7 +/- 3.9%, p < 0.05), and detumescence time (31.7 +/- 6.1 vs 78.6 +/- 12.8 sec, p < 0.01) in stress group when compared to control group. Thus, restraint stress declined detumescence time and decreased intracavernosal pressure in male rats. In conclusion, restraint stress model in rats may be useful for determining the effects of stress on erectile response. Even a short-term restraint stress may cause erectile dysfunction.

An experimental approach to the interrelationship between hyperthyroidism and ejaculation latency time in male rats.

PURPOSE: We investigated the effects of experimentally induced hyperthyroidism on seminal vesicle pressure measurements and bulbospongiosus muscle contractile activity in a para-chloroamphetamine (Sigma-Aldrich) induced ejaculation model in rats. MATERIALS AND METHODS: Male Wistar rats were used in the study. Daily injection of 25 microg/100 gm body weight L-thyroxine (T4, Sigma-Aldrich) for 14 days was performed in 14 rats to induce hyperthyroidism. Seven L-thyroxine injected rats were in the hyperthyroid group. The remaining 7 rats (recovery group) underwent operation after a 28-day washout period to determine spontaneous recovery from hyperthyroidism. At each operation seminal vesicle catheterization was done to measure intraluminal pressure and bulbospongiosus muscle dissection was performed for electromyography. After intraperitoneal administration of 5 mg/kg para-chloroamphetamine physiological parameters related to the ejaculatory process were measured. RESULTS: The interval between para-chloroamphetamine administration and first ejaculation was significantly decreased in the hyperthyroid rat group compared with that in the control group (mean +/- SD 202.8 +/- 22.3 vs 465.4 +/- 104.6 seconds, p = 0.001). Seminal vesicle phasic contraction frequency was significantly higher than control group values in hyperthyroid rats (for 30 minutes 32.3 +/- 13.9, p = 0.047). The mean AUC of bulbospongiosus muscle electromyography activity was also significantly increased in this group (11.1 +/- 4.1 V per second x 10(-4), p = 0.0001). All parameters in recovery and control group rats were not significantly differed from each other. CONCLUSIONS: Hyperthyroidism leads to enhanced seminal vesicle contraction frequency and bulbospongiosus muscle contractile activity in rats. Hyperthyroidism affects the emission and expulsion phases of ejaculation in reversible fashion.

Effects of partial bladder outlet obstruction on contraction and relaxation response of rabbit corpus cavernosum.

It has been well established that erectile dysfunction (ED) is a common incident in patients with benign prostate hyperplasia. Animal models have been described to investigate the relationship between bladder obstruction and ED. In this study, we aimed to investigate whether partial bladder outlet obstruction (PBOO) induces changes in the contraction and relaxation response of corpus cavernosum smooth muscle (CCSM) of the penis in the rabbit model. Partial bladder obstruction was performed in rabbits as previously described. After 2 and 4 weeks of follow-up, control, sham-operated (2- and 4-week duration) and partial bladder outlet obstructed (obstruction of 2- and 4-week duration) rabbits were sacrificed and their bladder masses determined. Then CCSM tissue was obtained. Contraction responses induced by 124 mM KCl, phenylephrine (10(-6) to 10(-4)M) and relaxation responses induced by doxazosin (10(-7) to 10(-5)M) in CCSM of rabbits were determined. The obtained contraction and relaxation responses of all groups were compared. Bladder weight was significantly higher in PBOO groups than in control and sham-operated rabbits. Contraction responses induced by KCl and phenylephrine were statistically enhanced in the 4-week PBOO groups than controls. However, there was no statistically significant difference in any KCl, phenylephrine and doxazosin responses between 2- and 4-week sham-operated and PBOO groups. The rabbit model of PBOO described for the studies which examine bladder responses is useful for creating bladder outlet obstruction. However, this model is not suitable for the investigation of outlet obstruction-related ED.

Effects of adenosine receptor antagonists on amitriptyline-induced QRS prolongation in isolated rat hearts.

OBJECTIVE: We investigated the effects of adenosine receptor antagonists on amitriptyline-induced cardiotoxicity in isolated rat hearts. METHODS: The amitriptyline concentrations that prolonged the QRS duration more than 150% (10(-4) M) and 50-75% (5.5 x 10(-5) M) were accepted as the control groups for two experimental protocols, respectively. In the first protocol, amitriptyline (10(-4) M) was infused following pretreatment with a selective adenosine A(1) receptor antagonist, DPCPX (8-cyclopentyl-1,3-Dipropylxanthine,10(-4) to 10(-6) M) or a selective adenosine A(2a) receptor antagonist, CSC (8-3-chlorostyryl-caffeine,10(-4) to 10(-6) M). In the second protocol, amitriptyline (5.5 x 10(-5) M) was infused following pretreatment with DPCPX (10(-4) M) or CSC (10(-5) M). Left ventricular developed pressure (LVDP), dp/dt(max), QRS duration and heart rate (HR) were measured. RESULTS: In the first protocol, 10(-4) M DPCPX pretreatment shortened QRS duration at 50 minutes when compared to the control group (p < 0.05). In the second protocol, pretreatment with 10(-4) M DPCPX shortened the QRS duration at 40, 50, and 60 minutes after amitriptyline infusion when compared to the control group (p < 0.05, p < 0.01 and p < 0.05, respectively). Pretreatment with 10(-5) M CSC prolonged QRS duration at 20, 30, and 60 minutes (p < 0.05). Amitriptyline infusion following pretreatment with DPCPX or CSC did not change LVDP, dp/dt(max), or HR when compared to control in both protocols (p > 0.05). CONCLUSION: While 10(-4) M DPCPX shortened QRS prolongation, 10(-5) M CSC prolonged QRS duration in the isolated rat hearts with prolonged QRS duration induced by 5.5 x 10(-5)M amitriptyline. An adenosine A(1) receptor antagonist, DPCPX, might shorten amitriptyline-induced QRS prolongation by activating beta adrenergic receptors.

[Quantification of papain-induced rat osteoarthritis in relation to time with the Mankin score]. / Siçanlarda papainle olusturulan osteoartritin Mankin skoru ile zamana bagli derecelendirilmesi.

OBJECTIVES: The aim of this study was to evaluate structural changes in relation to time with the use of the Mankin scoring system in papain-induced rat osteoarthritis. METHODS: Osteoarthritis was induced in 21 male Wistar rats by injecting an admixture of 4% papain (10 microl) and its activator 0.03 M cycteine (10 microl) into the right knee joints on the first, fourth, and seventh days. The same volume of sterile saline solution was injected into the left knees as controls. The rats were assigned to three groups equal in number and were sacrificed under high-dose ether anesthesia after one, two, and four weeks of the last papain injection, respectively. The study and control knee joints were removed and histologic changes in cartilage structure were assessed and quantified with the modified Mankin scoring system. RESULTS: Histologically, all papain injected knees exhibited irregularity and fibrillation in the superficial layer, decreased cell count and multilayering in transitional and radial zones, and no pannus formation. The modified Mankin scores were significantly higher compared to the control knees in all the groups (p<0.05), being 4.3+/-0.9, 6.9+/-1.3, and 10.4+/-1.9 in diseased knees, and 2.7+/-0.5, 4.0+/-0.8, and 4.4+/-1.0 in the control knees after one, two, and four weeks of the last papain injection, respectively. There was a significant difference between the Mankin scores of the rats sacrificed after one and four weeks of the last papain injection (p=0.0471). CONCLUSION: Findings observed after four weeks of papain injection seem to be consistent with early osteoarthritic changes. Our results may provide insight into therapeutic strategies for early osteoarthritis.

Effects of adenosine receptor antagonists on amitriptyline-induced vasodilation in rat isolated aorta.

BACKGROUND: Although we have previously demonstrated the beneficial effects of adenosine receptor antagonists in preventing cardiovascular toxicity of amitriptyline in rats, it is not clear whether adenosine receptors in heart or in vasculature are dominant. The aim of the current study was to investigate the role of adenosine A(2a) receptors on amitriptyline-induced vasodilation in rat isolated aorta. METHODS: After determining EC(80) of noradrenalin (NA) (the concentration of noradrenalin that produces 80% of maximal contractile response) as 10(-5)M, the IC(50) value of amitriptyline was measured in rat isolated aorta (the drug concentration causing a half- maximal inhibition of contractile responses to NA); IC(50) of amitriptyline was then compared in the presence of the DPCPX (a selective adenosine A(1) antagonist), CSC (a selective A(2a) antagonist) or DMSO (a solvent for adenosine antagonists). Statistical analysis was done using the Student t test. RESULTS: Amitriptyline-inhibited 49.9 +/- 3.7 % contractile response to NA on aorta segments at 1.8 x 10(-5)M (IC(50)). While DPCPX increased amitriptyline-induced inhibition on contractile response to NA dose dependently, CSC decreased the contractile response to NA only at 10(-5)M. DMSO did not change amitriptyline-induced IC(50). CONCLUSION: Adenosine A(2a) receptor stimulation seems to be responsible partly for amitriptyline-induced vasodilation and hypotension since the adenosine A(1) antagonist, DPCPX, increased amitriptyline-induced vasodilation in rat isolated aorta.

The effect of nonsteroidal anti-inflammatory drugs on rat gastric mucosa. The role of endothelin.

OBJECTIVE: To investigate the role of endothelin on nonsteroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase-2 (COX2) enzyme inhibitors-induced effects on the gastric mucosa. METHODS: This study was carried out in the Department of Pharmacology Laboratory, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey during the period January to December 2002. In the first group a cyclooxygenase-1 (COX1) and COX2 enzyme inhibitor, indomethacin (25 mg/kg, subcutaneous injection (s.c), n=7), a selective COX2 enzyme inhibitor, NS398 (10 mg/kg, s.c) and normal saline were administered. In the second group, endothelin-1 (ET1) was administered (200 pmol/kg) alone, in the presence of an endothelin receptor antagonist bosentan, (100 mg/kg) and PGE1 [40 microg/kg, orally] with submucosal injection. In the third group, NS398 and indomethacin were applied in the presence of bosentan. In the fourth group, NS398 were applied in the presence of N (G)-nitro-l-arginine methyl ester (L-NAME) (10 mg/kg, s.c). RESULTS: Indomethacin caused gastric mucosal injury. The effect of NS398 on gastric mucosa did not differ considerably from that of the control group. Submucosal injection of ET1 caused a gastric damage, which could not be prevented by intragastric administration of bosentan, while pretreatment with PGE1 prevented ET1-induced ulcer. Pretreatment with bosentan did not attenuate indomethacin-induced gastric mucosal damage but it increased NS398-induced damage by 1.5 fold. Pretreatment with L-NAME increased NS398-induced gastric mucosal damage as bosentan did. CONCLUSION: These results suggest that neither endothelin-induced nor indomethacin-induced ulcer is completely receptor dependent. Cyclooxygenase-2 inhibitors caused ulcer in the presence of bosentan. Protective effects of gastric mucosal injury of COX2 inhibitors may be via endothelin receptor related nitric oxide release.