Sedef Gidener

Effect of doxazosin with and without rho-kinase inhibitor on human corpus cavernosum smooth muscle in the presence of bladder outlet obstruction.

PURPOSE We investigated the relationship of adrenergic responses in corpus cavernosum tissues in the presence of BOO using the alpha1-adrenergic receptor antagonist doxazosin (Pfizer, New York, New York) and the rho-kinase inhibitor Y-27632 (Calbiochem, San Diego, California). MATERIALS AND METHODS CCSM tissue was obtained from patients who underwent penile prosthesis implantation. Patients were divided into 2 groups according to the presence of BOO. The submaximal (EC80) concentration of phenylephrine (Sigma Chemical Co., St. Louis, Missouri) was calculated by evaluating adrenergic activity responses with cumulatively applied phenylephrine. After achieving a stable contraction plateau test compounds were put in an organ bath. The relaxant potencies of doxazosin and Y-27632 were expressed as the percent of inhibition of the contraction plateau induced EC80 concentration of phenylephrine. Relaxation responses in the 2 groups were compared. RESULTS At the highest dose of increasing concentrations phenylephrine generated 70% more contraction response in the BOO positive group than in the BOO negative group. Doxazosin and Y-27632 caused concentration dependent relaxation in CCSM precontracted by phenylephrine. With doxazosin significantly higher relaxation responses were attained in the BOO positive group in terms of log IC50 and the maximal relaxation response (p = 0.0353 and 0.0003, respectively). Maximum relaxation responses following Y-27632 administration were significantly higher in the BOO positive group. CONCLUSIONS The contractility of human corpus cavernosum is increased in the presence of BOO. Doxazosin and Y-27632 generate effective CCSM relaxation in the presence of BOO. Doxazosin and Y-27632 may be the alternatives for the treatment of erectile dysfunction associated with BPH.

Evaluation of vascular smooth muscle and corpus cavernosum on hypercholesterolemia. Is resveratrol promising on erectile dysfunction

The aim of this study is to evaluate the effects of hypercholesterolemia in thoracic aorta (TA), mesenteric artery (MA), renal artery (RA), and corpus cavernosum (CC) isolated from cholesterol-fed rabbits. For determination of the maximum detrimental effect, vasorelaxation and vasoconstriction results of arteries and CC have been compared. Animals were fed with a diet that contained 2% w/w cholesterol and 2% w/w high cholesterol plus resveratrol (4 mg kg–1 per day) for 6-week duration. Total cholesterol levels in the plasma were measured. Vascular and endothelial functions in RA, TA, MA, and CC were assessed by isolated tissue bath with cumulative doses of acetylcholine and sodium nitroprusside. The statistical significance of differences of groups was analyzed by means of one-way ANOVA or Students t-test. P-values <0.05 were considered significant. There have been no significant changes on plasma total cholesterol levels between cholesterol and cholesterol + resveratrol-treated groups. Vasorelaxation responses to acetylcholine in resveratrol-treated group showed significant changes when compared with hypercholesterolemic group. No statistically significant differences were seen between non-receptor-mediated vasorelaxation responses between the three groups. Resveratrol might be an effective treatment in the prevention of atherosclerotic changes in arteries and CC. The initial effects of hypercholesterolemia on erectile dysfunction and endothelial dysfunction may be precluded with resveratrol. This protective effect may also ensure the prevention of coronary arterial diseases and renovascular diseases in hypercholesterolemic patients.

The Effect of Extracorporeal Electromagnetic Shock Waves on the Morphology and Contractility of Rabbit Ureter

PURPOSE Although extracorporeal shock wave lithotripsy (ESWL) is known to cause pathologic changes in various organs, little is known about its effects on the ureter, the target organ in ESWL of ureteral stones in situ. In this study, we sought to determine the short-term effects of ESWL on the ureter. MATERIALS AND METHODS Left lower ureteral segments of 21 rabbits were removed to serve as the control group and 2000 shocks were applied to the right lower ureters. Groups of 7 rabbits were sacrificed 1, 3 and 5 days after shock wave exposure. While histomorphological alterations were examined under light and transmission electron microscopy, contractility of all ureters was determined in organ baths. RESULTS The epithelial cells disclosed no change after shock wave application. Histologically the muscular layer was the most affected part of the ureter. There was interstitial and intracellular edema on light microscopy and marked chromatin and mitochondrial changes at the subcellular level. The adventitial layer was also edematous. These changes were prominent on days 1 and 3 and returned to normal on day 5. The contractility of the ureters on day 1 was significantly reduced (p < 0.05). However, the contractility of the samples on days 3 and 5 were not significantly different from controls. CONCLUSION Our findings demonstrate that electromagnetic shock waves produce reversible morphological and functional changes in rabbit ureteric muscle.

Do Adenosine Receptors Play a Role in Amitriptyline‐Induced Cardiovascular Toxicity in Rats?

Objective: The aim of the our study was to investigate the role of adenosine receptors on cardiovascular toxicity induced by amitriptyline, a tricyclic antidepressant agent. Therefore, the hypothesis of this study was that adenosine receptor antagonists would improve and/or prevent amitriptyline‐induced hypotension and conduction abnormalities in an anesthetized rat model of amitriptyline intoxication. Methods: Two separate experimental protocols were performed. Amitriptyline intoxication was induced by the infusion of amitriptyline 0.94 mg/kg/min until 40–45% reduction of mean arterial pressure (MAP). Sodium cromoglycate (10 mg/kg) was injected i.v. to inhibit the A3 receptor‐mediated activation of mast cells. In protocol 1, after amitriptyline infusion, while control animals (n = 8) were given dextrose solution, treatment groups received a selective adenosine A1 antagonist DPCPX (8‐cyclopentyl‐1,3‐Dipropylxanthine, 20 µg/kg/min, n = 8) or a selective A2a antagonist CSC (8‐(3‐chlorostyryl) caffeine, 24 µg/kg/min, n = 8) for 60 minutes. In protocol 2, after the sodium cromoglycate, while control group of rats (n = 8) recevied a dextrose solution, treatment groups of rats were administered DPCPX (20 µg/kg/min, n = 8) or CSC (24 µg/kg/min, n = 8) infusion to block adenosine A1 and A2a receptors for 20 minutes before amitriptyline infusion. After pretreatment with adenosine antagonists, all rats were given a dose of 0.94 mg/kg/min of amitriptyline infusion during 60 minutes. Outcome measures were mean arterial pressure (MAP), heart rate (HR), QRS duration and survival rate. Results: In protocol 1, amitriptyline infusion significantly reduced MAP and prolonged QRS within 15 minutes. HR was not changed significantly during the experiments. While dextrose did not improve MAP and QRS prolongation, DPCPX or CSC administration developed a significant improvement in MAP compared to the dextrose group within 10 min (88.5 ± 2.8%, 75.6 ± 4.7% and 50.1 ± 14.7%, p < 0.01, p < 0.05, respectively). Both DPCPX and CSC decreased QRS prolongation (p < 0.05) and increased median survival time significantly (log‐rank test, p < 0.00001). In protocol 2, pretreatment with DPCPX or CSC prevented the reduction in MAP due to amitriptyline toxicity compared to rats administered dextrose infusion (99.5 ± 2.6%, 102.4 ± 2.6%, 81.8 ± 5.4, p < 0.01 at 30 min; 98.0 ± 2.9%, 93.5 ± 6.0%, 64.9 ± 4.7, p < 0.001, p < 0.01 at 40 min, respectively). Pretreatment with DPCPX or CSC also prevented the QRS prolongation (p < 0.05) and increased median survival time significantly (log‐rank test, p < 0.0001). Conclusion: Adenosine antagonists were found to be effective in improving hypotension, QRS prolongation and survival time in our rat model of amitriptyline toxicity. Additionally, amitriptyline‐induced cardiotoxicity was abolished by pretreatment with adenosine receptor antagonists. These results suggest that adenosine receptors may have a role in the pathophysiology of amitriptyline‐induced cardiovascular toxicity. Adenosine A1 and A2a receptor antagonists may be promising agents for reversing amitriptyline‐induced cardiovascular toxicity.

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.

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.

In Vitro Adsorption of Dichlorvos and Parathion by Activated Charcoal

Accidental and suicidal ingestions of organophosphate compounds continue to be a common occurrence in Turkey. Activated charcoal administration without gastric emptying has been advocated as primary therapy in most acute poisoning cases, although some references do not recommend activated charcoal use in organophosphate poisoning. This study was performed to determine the in vitro adsorption of dimethyl dichlorovinyl phosphate (dichlorvos) and parathion by activated charcoal over a wide range of charcoal:organophosphate ratios (1:1, 2.5:1, 5:1, 10:1 and 20:1, g:g). The charcoal binding ability of dichlorvos and parathion were studied in both pH 1.2 and pH 7 environments. The supernatant was extracted with n-hexane and then analyzed by gas chromatography. Each incremental increase in charcoal dose increased the percent adsorption of dichlorvos and parathion. At the 20:1 ratio, 82.8 +/- 2.0/87.3 +/- 2.9% (pH 1.2/7.0) of dichlorvos and 59.3 +/- 4.5/64.5 +/- 6.1% (pH 1.2/7.0) of parathion were bound by activated charcoal. There were no significant differences in amounts of compound bound in the acid and neutral solutions. Large doses of activated charcoal effectively bind dichlorvos and parathion in vitro. In vivo research should be performed to determine activated charcoals role in organophosphate poisoning cases.

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 × 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 A1 receptor antagonist, DPCPX (8-cyclopentyl-1,3-Dipropylxanthine,10−4 to 10−6 M) or a selective adenosine A2a receptor antagonist, CSC (8-3-chlorostyryl-caffeine,10−4 to 10−6 M). In the second protocol, amitriptyline (5.5 × 10−5 M) was infused following pretreatment with DPCPX (10−4 M) or CSC (10−5 M). Left ventricular developed pressure (LVDP), dp/dtmax, 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/dtmax, 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 × 10−5M amitriptyline. An adenosine A1 receptor antagonist, DPCPX, might shorten amitriptyline-induced QRS prolongation by activating beta adrenergic receptors.

The effects of amrinone and glucagon on verapamil-induced myocardial depression in a rat isolated heart model

1. We measured the ability of glucagon and amrinone, used alone and in combination, to improve the myocardial function in a rat isolated heart model of calcium channel blocker (CCB) cardiotoxicity. 2. Verapamil 10(-4) mol consistently decreased heart rate and cardiac contractile force in our Langendorff rat isolated heart preparations. Glucagon increased the heart rate in a dose-dependent fashion. Amrinone increased the heart rate only at the 1 x 10(-1) mol concentration, and had no significant effect on cardiac contractility. 3. A positive linear correlation was found between the glucagon concentration and the percent recovery of baseline contractile force. 4. Although complete reversal of verapamil-induced myocardial depression occurred at glucagon concentrations of > 3 x 10(-6) mol, amrinone produced only 23.8 +/- 3.6% recovery from baseline at its highest concentration (4 x 10(-3) mol). 5. When glucagon and amrinone were administered together, there was no additional increase over glucagon alone in the increase in contractile force. 6. Glucagon, and not amrinone, is an appropriate agent, capable of reversing verapamil-induced myocardial toxicity in this rat isolated heart model. In vivo studies should be performed to assess whether this may be a reliable therapy in clinical cases.

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 µM) 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.