Pharmacological characterisation of the CB1 receptor antagonist activity of cannabidiol in the rat vas deferens bioassay.

Cannabidiol is increasingly considered for treatment of a wide range of medical conditions. Binding studies suggest that cannabidiol binds to CB1 receptors. In the rat isolated vas deferens bioassay, a single electrical pulse causes a biphasic contraction from nerve-released ATP and noradrenaline. WIN 55,212-2 acts on prejunctional CB1 receptors to inhibit release of these transmitters. In this bioassay, we tested whether cannabidiol and SR141716 were acting as competitive antagonists of this receptor. Monophasic contractions mediated by ATP or noradrenaline in the presence of prazosin or NF449 (P2X1 inhibitor), respectively, were measured to a single electrical pulse delivered every 30 min. Following treatment with cannabidiol (10-100 µM) or SR141716 (0.003-10 µM), cumulative concentrations of WIN 55,212-2 (0.001-30 µM) were applied followed by a single electrical pulse. The WIN 55,212-2 concentration-contraction curve EC50 values were applied to global regression analysis to determine the pKB. The antagonist potency of cannabidiol at the CB1 receptor in the rat vas deferens bioassay matched the reported receptor binding affinity. Cannabidiol was a competitive antagonist of WIN 55,212-2 with pKB values of 5.90 when ATP was the effector transmitter and 5.29 when it was noradrenaline. Similarly, SR141716 was a competitive antagonist with pKB values of 8.39 for ATP and 7.67 for noradrenaline as the active transmitter. Cannabidiol's low micromolar CB1 antagonist pKB values suggest that at clinical blood levels (1-3 µM) it may act as a CB1 antagonist at prejunctional neuronal sites with more potency when ATP is the effector than for noradrenaline.

Sialorphin Potentiates Effects of [Met5]Enkephalin without Toxicity by Action other than Peptidase Inhibition.

This dose-response study investigated the effects of sialorphin on [Met5]enkephalin (ME)-induced inhibition of contractions in mouse vas deferens and antinociception in male rats. Differences were compared among combinations of three chemical peptidase inhibitors: amastatin, captopril, and phosphoramidon. The ratio of potencies of ME in mouse vas deferens pretreated with both sialorphin (100 µM) and a mixture of the three peptidase inhibitors (1 µM each) was higher than that with the mixture of peptidase inhibitors alone at any dose. Intrathecal administration of sialorphin (100-400 nmol) significantly and dose dependently increased ME (3 nmol)-induced antinociception with the mixture of three peptidase inhibitors (10 nmol each). The degree of antinociception with a combination of any two of the peptidase inhibitors (10 nmol each) in the absence of sialorphin was less than that in the presence of sialorphin (200 nmol). Pretreatment with both sialorphin (200 nmol) and the mixture of three peptidase inhibitors (10 nmol each) produced an approximately 100-fold augmentation in ME (10 nmol)-induced antinociception, but without signs of toxicity such as motor dysfunction in rats. Radioligand receptor binding assay revealed that sialorphin did not affect either binding affinity or maximal binding capacity of [d-Ala2,N-MePhe4,Gly-ol5]enkephalin. These results indicate that sialorphin potentiates the effects of ME without toxicity by a mechanism other than peptidase inhibition and with no effect on its affinity to µ-opioid receptors. SIGNIFICANCE STATEMENT: Sialorphin is regarded as an endogenous peptidase inhibitor that interacts with enkephalin-degrading enzymes. The results of these in vitro and in vivo studies confirm that sialorphin potentiates the effects of [Met5]enkephalin without toxicity by an action other than peptidase inhibition. This suggests that sialorphin offers the advantage of reducing or negating the side effects of opioid drugs and endogenous opioid peptides.

Synthesis of 2-phenyl-5,6,7,8-tetrahydroquinoxaline derivatives and screening for P2X1-purinoceptor antagonist activity in isolated preparations of rat vas deferens, for translation into a male contraceptive†.

Sympathetically mediated contractions of smooth muscle cells in the vasa deferentia are mediated by neuronally released adenosine 5'-triphosphate (ATP) and noradrenaline, which stimulate P2X1-purinoceptors and α1A-adrenoceptors, respectively. This process is crucial for sperm transport, as demonstrated in knockout mouse studies where simultaneous genetic deletion of P2X1-purinoceptors and α1A-adrenoceptors resulted in male infertility. We hypothesize that dual pharmacological antagonism of these two receptors could inhibit sperm transport sufficiently to provide a novel nonhormonal method of male contraception. To generate a suitable P2X1-purinoceptor antagonist, substituents were introduced on the phenyl moiety of 2-phenyl-5,6,7,8-tetrahydroquinoxaline to create a series of analogues that were tested for P2X1-purinoceptor antagonism in isolated preparations of rat vas deferens. Novel compounds were initially screened for their ability to attenuate contractile responses to electrical field stimulation (EFS: 60 V, 0.5 ms, 0.2 Hz). The addition of polar substituents to the meta, but not ortho, position markedly increased the inhibition of contractions, as did the addition of both polar and aliphatic substituents to the para position. Di-substituted compounds were also synthesized and tested, resulting in a compound 31 (2-hydroxy, 4-fluoro), which exhibited the greatest potency, with an IC50 of 14 µM (95% confidence limits: 12-16 µM). Additionally, compound 31 noncompetitively antagonized contractions mediated by exogenously administered αß-methylene ATP (10 nM-30 µM) but had no inhibitory effect on contractions mediated by exogenously administered noradrenaline (30 nM-100 µM) or acetylcholine (30 nM-100 µM). These results have contributed to a structure-activity relationship profile for the P2X1-purinoceptor that will inform future designs of more potent antagonists.

Neurotoxicity of Tityus bahiensis (brown scorpion) venom in sympathetic vas deferens preparations and neuronal cells.

Systemic scorpion envenomation is characterized by massive neurotransmitter release from peripheral nerves mediated primarily by scorpion venoms neurotoxins. Tityus bahiensis is one of the medically most important species in Brazil, but its venom pharmacology, especially regarding to peripheral nervous system, is poorly understood. Here, we evaluated the T. bahiensis venom activity on autonomic (sympathetic) neurotransmission by using a variety of approaches, including vas deferens twitch-tension recordings, electrophysiological measurements (resting membrane potentials, spontaneous excitatory junctional potentials and whole-cell patch-clamp), calcium imaging and histomorphological analysis. Low concentrations of venom (≤ 3 µg/mL) facilitated the electrically stimulated vas deferens contractions without affecting postsynaptic receptors or damaging the smooth muscle cells. Transient TTX-sensitive sustained contractions and resting membrane depolarization were mediated mainly by massive spontaneous ATP release. High venom concentrations (≥ 10 µg/mL) blocked the muscle contractions and induced membrane depolarization. In neuronal cells (ND7-23wt), the venom increased the peak sodium current, modified the current-voltage relationship by left-shifting the Nav-channel activation curve, thereby facilitating the opening of these channels. The venom also caused a time-dependent increase in neuronal calcium influx. These results indicate that the sympathetic hyperstimulation observed in systemic envenomation is presynaptically driven, probably through the interaction of α- and ß-toxins with neuronal sodium channels.

Effect of indole alkaloids from roots of Rauvolfia ligustrina in the noradrenergic neurotransmission.

The new glucosyl sarpagan alkaloid designated as 21(R*)-(O-ß-glucosyl)-hydroxy-sarpagan-17-oic acid, along with eleven known alkaloids were isolated from a soluble alkaloidal fraction from the ethanol extract of Rauvolfia ligustrina. Their structures were elucidated by interpretation of spectroscopic data (1D and 2D NMR), HRESIMS experiment, GIAO 13C NMR calculations, and comparison with literature data. All the isolated alkaloids were screened by their neuroinhibitory effects using the electrically stimulated mice vas deferens bioassay. Compounds 1, 2 and 9 presented a potent inhibitory effect in the neurotransmission while 3 and 11 showed an acute neuroexcitatory effect. Compound 10 exhibited a very effective post-synaptic inhibitory activity.

Infliximab prevents dysfunction of the vas deferens by suppressing inflammation and oxidative stress in rats with chronic stress.

AIMS: Chronic stress leads to the development of male sexual problems such as ejaculatory dysfunctions. The rhythmic contractions of vas deferens (VD) play an important role on the ejaculatory process. In the current study, we investigated whether infliximab (IFX) treatment has any beneficial effects on possible alterations in contractility of VD obtained from rats exposed to unpredictable chronic mild stress (UCMS). MATERIALS AND METHODS: The rats were randomly divided into four groups: control, control+IFX, UCMS and UCMS+IFX. IFX (5 mg/kg/week, i.p.) was administrated for 5 weeks during UCMS period. Depressive like-behaviors were evaluated using locomotor activity, forced swimming and sucrose consumption and preference tests. The blood was collected for serum biochemical determinations. VD tissues were harvested for functional studies and, measurements of oxidative stress, inflammatory and apoptotic biomarkers. KEY FINDINGS: We observed increased serum concentration of corticosterone and depressive-like behaviors in rats exposed to UCMS. In VD tissues of UCMS-exposed rats, noradrenaline- and adenosine triphosphate (ATP)-induced contractile responses significantly enhanced and electrical field stimulation (EFS)-induced contractile responses markedly decreased. UCMS exposure induced inflammation, oxidative stress and apoptosis in VD. However, IFX treatment significantly improved all the aforementioned parameters. SIGNIFICANCE: The results of the present study revealed that chronic stress-induced depression caused VD dysfunction by promoting inflammation and oxidative stress in VD. IFX protected against VD dysfunction through its anti-inflammatory and antioxidant effects.

Resveratrol and quercetin attenuate depressive-like behavior and restore impaired contractility of vas deferens in chronic stress-exposed rats: involvement of oxidative stress and inflammation.

Chronic stress is associated with male sexual problems including ejaculatory dysfunctions. The aim of this study was to determine whether resveratrol (RS) or quercetin (QE) has protective effects on vas deferens (VD) contractility in the unpredictable chronic mild stress (UCMS) rat model of depression. Animals were separated into six groups: control, control + RS and control + QE, stress, stress + RS, and stress + QE. Stress groups were subjected to UCMS procedure for 5 weeks. Animals in treatment groups were injected intraperitoneally with RS (20 mg/kg) or QE (30 mg/kg) for 5 weeks during UCMS period. UCMS caused depressive-like behaviors and enhanced systemic levels of corticosterone. The nerve-evoked contractile responses of VD significantly impaired and, noradrenaline- and ATP-induced contractile responses of VD significantly increased in stressed rats. UCMS exposure also markedly enhanced oxidative stress and inflammation in VD tissues. Treatment with RS or QE significantly ameliorated all the aforementioned parameters. The current study demonstrated that RS or QE protected against chronic stress-induced VD dysfunction by their antioxidant and anti-inflammatory effects on VD, suggesting that oxidative stress and inflammation may be synergistic parts in the development of VD dysfunction associated with chronic stress-induced depression.

The effects of varying Mg2+ ion concentrations on contractions to the cotransmitters ATP and noradrenaline in the rat vas deferens.

The vas deferens responds to a single electrical pulse with a biphasic contraction caused by cotransmitters ATP and noradrenaline. Removing Mg2+ (normally 1.2 mM) from the physiological salt solution (PSS) enhances the contraction. This study aimed to determine the effect of Mg2+ concentration on nerve cotransmitter-mediated contractions. Rat vasa deferentia were sequentially bathed in increasing (0, 1.2, 3 mM) or decreasing (3, 1.2, 0 mM) Mg2+ concentrations. At each concentration a single field pulse was applied, and the biphasic contraction recorded. Contractions to exogenous noradrenaline 10 µM and ATP 100 µM were also determined. The biphasic nerve-mediated contraction was elicited by ATP and noradrenaline as NF449 (10 µM) and prazosin (100 nM) completely prevented the respective peaks. Taking the contractions in normal PSS (Mg2+ 1.2 mM) as 100%, lowering Mg2+ to 0 mM enhanced the ATP peak to 170 ±â€¯7% and raising Mg2+ to 3 mM decreased it to 39 ±â€¯3%; the noradrenaline peak was not affected by lowering Mg2+ to 0 mM (97 ±â€¯3%) but was decreased to 63 ±â€¯4% in high Mg2+ (3 mM). Contractions to exogenous ATP, but not noradrenaline, were increased in Mg2+ 0 mM and both were inhibited with Mg2+ 3 mM. Changing Mg2+ concentration affects the contractions elicited by the cotransmitters ATP and noradrenaline. The greatest effects were to potentiate the contraction to ATP in Mg2+ 0 mM and to inhibit the contraction to both ATP and noradrenaline in high Mg2+. Future publications should clearly justify any decision to vary the magnesium concentration from normal (1.2 mM) values.

Safety & efficacy of an intravasal, one-time injectable & non-hormonal male contraceptive (RISUG): A clinical experience.

Background & objectives: For improved male contraception, a new polymeric drug molecule - Reversible Inhibition of Sperm under Guidance (RISUG) has been synthesized and has been found to be effective, safe and reversible in various animal species. Phase-I and phase-II clinical trials have confirmed its safety and contraceptive efficacy. The present study was undertaken as a multicentric-limited phase-III clinical trial to test the efficacy and safety of RISUG in human volunteers. Methods: One hundred and thirty nine young males each having at least two children and living with wife were given 120 µl of RISUG as bilateral vas intraluminal injection. After the single-dose administration, the individuals were followed in respect of general health and semen parameters. Their wives were also followed particularly to determine onset of pregnancy. Results: During the six month follow up, the health of male volunteers and their wives was normal with no significant adverse effects. Temporary scrotal enlargement and mild scrotal and inguinal region pain were manifested in most individuals and resolved within one month without any routine activity impairment. In six individuals, there was injection procedure failure and azoospermia was not achieved. The other 133 individuals had either severe oligozoospermia or azoospermia at the first semen examination one month following RISUG injection; 82.7 per cent individuals had continued azoospermia in the month following first semen examination onwards and the rest 17.3 per cent manifested azoospermia within three to six months. Interpretation & conclusions: RISUG intravasal injection appears to be a safe clinical procedure with no significant adverse effects and has high sustained contraceptive efficacy. The localized intervention and continued contraceptive action on single-dose administration were significant features of the RISUG technology.

Castration Induces Down-Regulation of A-Type K+ Channel in Rat Vas Deferens Smooth Muscle.

A-type K+ channels contribute to regulating the propagation and frequency of action potentials in smooth muscle cells (SMCs). The present study (i) identified the molecular components of A-type K+ channels in rat vas deferens SMs (VDSMs) and (ii) showed the long-term, genomic effects of testosterone on their expression in VDSMs. Transcripts of the A-type K+ channel α subunit, Kv4.3L and its regulatory ß subunits, KChIP3, NCS1, and DPP6-S were predominantly expressed in rat VDSMs over the other related subtypes (Kv4.2, KChIP1, KChIP2, KChIP4, and DPP10). A-type K+ current (IA) density in VDSM cells (VDSMCs) was decreased by castration without changes in IA kinetics, and decreased IA density was compensated for by an oral treatment with 17α-methyltestosterone (MET). Correspondingly, in the VDSMs of castrated rats, Kv4.3L and KChIP3 were down-regulated at both the transcript and protein expression levels. Changes in Kv4.3L and KChIP3 expression levels were compensated for by the treatment with MET. These results suggest that testosterone level changes in testosterone disorders and growth processes control the functional expression of A-type K+ channels in VDSMCs.

Effects of mu opioid receptors in paraventricular nucleus on ejaculation through mediating sympathetic nerve system activity.

To investigate the roles of mu opioid receptors (MORs) in paraventricular nucleus of the hypothalamus (PVN) on ejaculation and its underlying mechanism in the rats, we performed copulation behavioral testing and acute experiments. During the acute experiments, mean arterial pressure (MAP), heart rate (HR), bulbospongiosus muscle-electromyogram (BSM-EMG) and pressure of vas deferens (PVD) were all recorded. The expression levels and distributions of opioid receptors were also assessed in PVN of male rats. Moreover, adeno-associated virus type 1 (AAV1) was microinjected into PVN to demonstrate whether there are direct projections from PVN to lumbar spinothalamic (LSt) cells. We found that microinjection of MOR agonist, D-A1a2-NM9-Phe4-Gly(ol)5enkephalin (DAGO), into the PVN prolonged the intromission latency and inhibited ejaculation (P = 0.0241, P = 0.0473, respectively), while the opposed results appeared in CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2, MOR antagonist) group (P = 0.0021, P = 0.0286, respectively). Moreover, DAGO caused a significant decrease in MAP and HR (P = 0.0065, P = 0.0030, respectively), and PVD decreased significantly after DAGO microinjection in PVN (P = 0.0383). CTAP not only blocked the effect of DAGO but also significantly increased MAP, HR and PVD (P = 0.0003, P = 0.0010, P = 0.0074, respectively). Meanwhile, a significant increase was observed in BSM-EMG activity after microinjecting of CTAP (P = 0.0022), accompanied by visible BSM contraction. Additionally, anterograde monosynaptic transneuronal tracer AAV1 labeling revealed that neurons in PVN projected directly to LSt cells in L3-4 spinal cord. These results indicate that MORs in PVN centrally mediate ejaculation by regulating the sympathetic outflow, which may be treated as a therapeutic target for ejaculation disorders in the future.

Butylidenephthalide facilitates contractions via nonspecific binding to receptors in isolated guinea-pig vas deferens.

Context: Butylidenephthalide (Bdph) has been reported to inhibit rat uterine contractions, but significantly potentiate the noradrenaline (NA)-induced contractions in guinea-pig vas deferens (GPVDs). Objective: The present study elucidates the binding specificity of Bdph in GPVD to potentiate contractions. Materials and methods: Electrical field stimulation (EFS, supramaximal voltage, 1 ms and 1 Hz) or exogenous NA (50 µM) was applied to the GPVD in Krebs or 1/10 Mg-Tyrode's solution, respectively. After the clonidine (10 nM)-induced twitch inhibition or the exogenous NA-induced contractions reached a constant, Bdph (50 µM) was added 2 min prior to the subsequent addition of NA (50 µM). Three experiments were performed. In the presence of Bdph (100 µM), the release of NA in the medium and remaining NA content in the tissues were determined after EFS-stimulation. Results: Bdph (100 µM) significantly antagonized the clonidine (10 nM)-induced twitch inhibition from 22.5 ± 2.1 to -11.4 ± 1.6% (n = 6) and dibutyryl-cAMP (300 µM) from 25.7 ± 3.2 to 7.9 ± 4.0% (n = 8). Bdph (100 µM) significantly increased the electrically stimulated release of NA from 393.0 ± 109.5 to 1000.0 ± 219.1 ng/g (n = 6). Bdph (50 µM) potentiated the exogenous NA (50 µM)-induced contractions from 3.0 ± 0.06 to 3.9 ± 0.06 g (n = 3), but after washout of Bdph, the response to NA gradually curtailed. Discussion and conclusions: Bdph action may be through the nonspecific binding of the butylidene group to prejunctional α2- and postjunctional α1-adrenoceptors to reversibly block K+ channels, and irreversibly block VDCCs on the smooth muscle cell membrane, respectively.

Vasitis: a rare diagnosis mimicking inguinal hernia: a case report.

BACKGROUND: Vasitis or inflammation of the vas deferens is a rare condition, and few case reports with computed tomography images have been published since 1980. CASE PRESENTATION: A 50-year-old man presented with severe right inguinal and lower abdominal pain. Initial diagnosis at the emergency department was incarcerated or strangulated inguinal hernia. The computed tomography scan revealed diffuse edematous changes of right spermatic cord and vas deferens with peripheral fat stranding. Correlating with his clinical symptoms, signs, and imaging findings, the diagnosis of vasitis was made. We report a case of acute vasitis about the cause, symptom, pathogen, differential diagnoses, image findings, and treatment. CONCLUSION: Although very rare, vasitis should be listed as one of the differential diagnosis for inguinal mass lesions. Cross-sectional imaging may be necessary to confirm the diagnosis and exclude differentials such as an inguinal hernia. Recognition of the characteristic image findings can help to make the correct diagnosis and avoid unnecessary surgery.

Comparison of the Effects of Tadalafil and α1-Adrenoceptor Antagonists on Spontaneous Seminal Emission and Electrical Field Stimulation-Induced Seminal Vesicle Contraction in Rats.

BACKGROUND: Although numerous reports have shown that α1-adrenoceptor (α1-AR) antagonists, which are used to treat benign prostatic hyperplasia (BPH), can cause ejaculatory disorders, few studies have investigated whether the phosphodiesterase 5 (PDE5) inhibitor tadalafil has such adverse effects. In this study, we compared the effects of tadalafil and α1-AR antagonists on seminal emission and their mechanisms of action. AIM: To evaluate in normal rats the possible effects of tadalafil on spontaneous seminal emission (SSE) and seminal contraction evoked by hypogastric nerve stimulation. METHODS: Male Sprague-Dawley rats were used. To assess SSE, plastic corsets were fitted around the thorax and upper abdomen of male Sprague-Dawley rats to prevent genital autogrooming. Rats were treated orally with tadalafil or an α1-AR antagonist (silodosin, naftopidil, or tamsulosin) for 3 days and housed in wire-bottomed cages. Ejaculatory plugs dropped on the bottoms of the cages were counted and weighed. To assess the intraluminal pressure of seminal vesicles, the hypogastric nerve of urethane-anesthetized rats was isolated and electrically stimulated. After stabilization of seminal vesicle contraction, the rats were intravenously administered test drugs. The expression of PDE5, endothelial nitric oxide synthetase (eNOS), and neuronal NOS (nNOS) in the seminal vesicle and vas deferens were measured by reverse-transcription polymerase chain reaction. MAIN OUTCOME MEASURE: The number and weight of the ejaculatory plugs produced by corset-fitted rats and the intraluminal pressure of the seminal vesicle were evaluated. RESULTS: Tadalafil did not affect the number or weight of the ejaculatory plugs of corset-fitted rats, whereas all α1-AR antagonists decreased both in a dose-dependent manner. The α1-AR antagonists, but not tadalafil, inhibited the seminal vesicle contraction evoked by electrical stimulation of the hypogastric nerve. The seminal vesicle and vas deferens expressed higher levels of PDE5 and eNOS mRNA and lower levels of nNOS mRNA relative to the urethra. CLINICAL IMPLICATIONS: Tadalafil can be a treatment option in cases where there is concern about negative effects on seminal emission. STRENGTHS AND LIMITATIONS: We demonstrated different effects of tadalafil and 3 α1-AR antagonists on rat SSE and their mechanisms of action by measuring seminal vesicle contractility in vivo. A limitation is that we used normal rats, not BPH model rats, and so our results might not apply to human BPH patients. CONCLUSION: Tadalafil did not inhibit spontaneous seminal emission or electrical field stimulation-induced seminal vesicle contraction in normal rats. The NO-cyclic guanosine monophosphate pathway is unlikely to be involved in the inhibition of seminal vesicle contraction in normal rats. Yoshinaga R, Fukui T, Yoshifuji M, et al. Comparison of the Effects of Tadalafil and α1-Adrenoceptor Antagonists on Spontaneous Seminal Emission and Electrical Field Stimulation-Induced Seminal Vesicle Contraction in Rats. J Sex Med 2019;16:680-690.

Evaluation of Antidepressant Effects on Recovery of Electrical Field Stimulation-Induced Contractions that have been Suppressed by Clonidine in Isolated Rat Vas Deferens.

BACKGROUND: A report examining whether clinically available antidepressants increase urethral smooth muscle contraction via antagonistic effects on the α2-adrenoceptor (α2-AR) is lacking. OBJECTIVES: The present study was performed to evaluate the potential of clinically available antidepressants to reverse α2-AR-mediated contractile inhibition in rat vas deferens, in order to predict whether they can induce voiding impairment. METHOD: The effects of 18 antidepressants of different classes on electrical field stimulation (EFS)-induced contractions suppressed by 10-8 mol/L clonidine (a selective α2-AR agonist) in isolated rat vas deferens were investigated and related to their respective clinical blood concentrations. RESULTS: The EFS-induced contractions suppressed by clonidine were recovered by amitriptyline (a tricyclic antidepressant), mirtazapine (a noradrenergic and specific serotonergic antidepressant), and trazodone (a serotonin 5-HT2A receptor antagonist) at concentrations close to the clinical blood levels. EFS-induced contractions were also recovered by trimipramine, clomipramine (tricyclic antidepressants), mianserin (a tetracyclic antidepressant), sertraline (a selective serotonin reuptake inhibitor [SSRI]), and sulpiride (a dopamine D2-receptor antagonist), albeit at concentrations that substantially exceeded their clinically-achievable blood levels. EFS-induced contractions were not significantly affected by imipramine, nortriptyline, amoxapine (tricyclic antidepressants), maprotiline (a tetracyclic antidepressant), fluvoxamine, paroxetine, escitalopram (SSRIs), milnacipran, duloxetine (serotonin and noradrenaline reuptake inhibitors), and aripiprazole (a dopamine partial agonist). CONCLUSIONS: These findings suggest that amitriptyline, mirtazapine, and trazodone induce voiding impairment caused by increased urethral resistance by enhancing sympathetic nerve activities attributed to α2-AR antagonism.

Effect of dietary inclusion of small quantities of Mucuna pruriens seed meal on sexual behavior, semen characteristics, and biochemical parameters in rabbit bucks (Oryctolagus cuniculus).

The aim of this work was to investigate the effects of Mucuna pruriens seed meal (MSM) on sexual behavior, semen, and biochemical parameters in rabbit bucks. Twenty-four 12-week-old rabbit bucks weighing 1002 to 1156 g were randomly allocated to three experimental diets containing 0, 1.5, and 3% of MSM in a 3-month trial. Sexual behavior parameters such as mounting latency, mounting frequency, successful mounting frequency, intromission latency, and post ejaculatory interval were monitored at the end of the experiment by mating with receptive females. Thereafter, rabbits were weighed, stunned, and humanely sacrificed and testes, epididymis, and vas deferens were harvested for evaluation of organ weights and semen characteristics. Results indicate that supplementing rabbit diet with MSM induced a significant decrease (P < 0.05) in mounting latency (69.7%) and intromission latency (19.7%), while it significantly (P < 0.05) increased successful mounting frequency (60%) as well as relative weight of testis (33.3%) and vas deferens (54.5%). There was a dose-dependent increase (P < 0.05) in sperm motility (35.7%) and concentration (65.9%), serum albumin (19.1%) and protein concentration (9.9%), and a decrease in sperm morphological alterations (68.3%), serum cholesterol (13.4%), and urea (11.6%) in treatment groups where MSM was supplemented at 3% compared to controls. From the findings, it appears MSM is a potential enhancer of male reproductive performance that can be recommended to rabbit farmers for improving reproductive performance and quality of semen, hence a boon to reproduction and production in rabbit farming industry.

Methylhexaneamine causes tachycardia and pressor responses indirectly by releasing noradrenaline in the rat.

We have investigated the mode of cardiovascular action of the stimulant methylhexaneamine (MHA) in terms of direct or indirect adrenergic actions in anaesthetised rats. Male and female rats were anaesthetised with pentobarbitone and pressor (changes in diastolic blood pressure) and cardioaccelerator responses to MHA were examined in vehicle treated or chemically sympathectomised rats. MHA produced pressor and cardioaccelerator responses over the same dose range in vehicle treated animals, with significant cardioaccelerator and pressor responses occurring at MHA (0.1 mg/kg). However, tachycardia was more marked than pressor responses. In sympathectomised rats, cardiac and pressor actions of MHA were greatly attenuated. MHA was also studied in isolated tissues. In rat vas deferens, MHA produced small tonic contractions, but these were virtually abolished by sympathectomy In rat aorta, MHA produced almost no contractions. These results are also consistent with largely indirect actions. There were no differences between male and female rats. It is concluded that MHA acts predominantly indirectly in both male and female rats causing noradrenaline release to produce cardiovascular actions and that as a result pressor and cardiac responses occur at similar doses. This propensity for MHA to cause tachycardia and rises in blood pressure at similar doses range may have implications for adverse cardiovascular actions.

Hormonal control of vas deferens fluid volume and aquaporin expression in rats.

Precise regulation of vas deferens fluid volume which is important for sperm survival might be influenced by testosterone. In order to investigate changes in vas deferens fluid volume and aquoporins (AQP) isoforms expression under testosterone influence, orchidectomized Sprague-Dawley rats were given 125 and 250 µg/kg/day testosterone with or without flutamide, an androgen receptor blocker or finasteride, a 5alpha-reductase inhibitor for seven consecutive days. Following treatment completion, vas deferens was perfused and changes in the fluid secretion rate and osmolality were determined in the presence of acetazolamide. Rats were then sacrificed and vas deferens was harvested for histology, tissue expression and distribution analyses of AQP-1, AQP-2, AQP-5, AQP-7 and AQP-9 proteins by Western blotting and immunohistochemistry, respectively. Our findings indicate that testosterone causes vas deferens fluid secretion rate to increase, which was antagonized by acetazolamide. Fluid osmolality increased following testosterone treatment and further increased when acetazolamide was given. Co-administration of flutamide or finasteride with testosterone causing both fluid secretion rate and osmolality to decrease. Histology revealed increased size of vas deferens lumen with increased thickness of vas deferens stroma. Expression of AQP-1, AQP-2 and AQP-9 were detected in vas deferens but not AQP-5 and AQP-7, and the levels of these proteins were increased by testosterone treatment mainly at the apical membrane of vas deferens epithelium. In conclusion, increased in vas deferens fluid secretion rate under testosterone influence mediated via the up-regulation of AQP-1, 2 and 9 might be important for vas deferens fluid homeostasis in order to ensure normal male fertility.

Drug-receptor kinetics and sigma-1 receptor affinity differentiate clinically evaluated histamine H3 receptor antagonists.

The histamine H3 receptor is a G protein-coupled receptor (GPCR) drug target that is highly expressed in the CNS, where it acts as both an auto- and hetero-receptor to regulate neurotransmission. As such, it has been considered as a relevant target in disorders as varied as Alzheimer's disease, schizophrenia, neuropathic pain and attention deficit hyperactivity disorder. A range of competitive antagonists/inverse agonists have progressed into clinical development, with pitolisant approved for the treatment of narcolepsy. Given the breadth of compounds developed and potential therapeutic indications, we assessed the comparative pharmacology of six investigational histamine H3 agents, including pitolisant, using native tissue and recombinant cells. Whilst all of the compounds tested displayed robust histamine H3 receptor inverse agonism and did not differentiate between the main H3 receptor splice variants, they displayed a wide range of affinities and kinetic properties, and included rapidly dissociating (pitolisant, S 38093-2, ABT-239) and slowly dissociating (GSK189254, JNJ-5207852, PF-3654746) agents. S 38093-2 had the lowest histamine H3 receptor affinity (pKB values 5.7-6.2), seemingly at odds with previously reported, potent in vivo activity in models of cognition. We show here that at pro-cognitive and anti-hyperalgesic/anti-allodynic doses, S 38093-2 preferentially occupies the mouse sigma-1 receptor in vivo, only engaging the histamine H3 receptor at doses associated with wakefulness promotion and neurotransmitter (histamine, ACh) release. Furthermore, pitolisant, ABT-239 and PF-3654746 also displayed appreciable sigma-1 receptor affinity, suggesting that this property differentiates clinically evaluated histamine H3 receptor antagonists and may play a role in their efficacy.

Imposex in Stramonita haemastoma from coastal sites of Cartagena, Colombia / Imposex em Stramonita haemastoma em locais costeiros de Cartagena, Colômbia

Abstract Imposex is the development of male sexual characteristics caused by the toxic effects of some chemicals that acts as an endocrinal disruptor. Antifouling paints contain these chemicals. Cartagena lacks studies to indicate the extent of imposex in its coastal waters. The aim of this study was to determine the prevalence of imposex in the gastropod Stramonita haemastoma in Cartagena, Colombia. Specimens were collected during 2013 from locations of high and low influence of port activity. Morphometric measurements and the frequency of the occurrence of imposex were registered. The comparison among morphometric variables showed statistically significant differences between the two sites studied. Furthermore, the females of the S. haemastoma species presented an imposex frequency of 93.1% in Birds' Island, Cartagena Bay, compared to 31.8% in La Bocana. The relative penis size index or RPLI (10.145 and 3.231) and vas deferens sequence index or VDSI (2.83 and 1.16), showed possible contamination by organotin compounds in both places.

Resumo Imposex é o desenvolvimento de características sexuais masculinas causadas por poluentes tóxicos de alguns produtos químicos que atuam como desreguladores endócrinos. Tintas anti-incrustantes são as que contêm estes produtos químicos. Cartagena carece de estudos para indicar a extensão do imposex nas suas águas costeiras. O objetivo deste estudo foi determinar a prevalência de imposex no gastrópode Stramonita haemastoma em Cartagena, Colômbia. Os espécimes foram coletados durante 2013 de locais de alta e baixa influência da atividade portuária. Foram registradas as medidas morfométricas e a frequência da ocorrência do imposex. A comparação entre as variáveis morfométricas mostrou diferenças estatisticamente significantes entre os dois locais estudados. Além disso, as fêmeas da espécie S. haemastomaapresentaram uma frequência de imposex de 93,1% na Ilha das Aves, Baía das Cartagena, em comparação com 31,8% em La Bocana. O índice do comprimento relativo do pênis ou RPLI (10,145 e 3,231) e o índice da sequência do vaso deferente ou VDSI (2,83 e 1,16), mostraram possível contaminação por compostos organoestânicos em ambos os locais.