Efficacy and safety of repeated dosing of netupitant, a neurokinin-1 receptor antagonist, in treating overactive bladder.

AIM: NK-1 receptors in sensory nerves, the spinal cord and bladder smooth muscle participate in complex sensory mechanisms that regulate bladder activity. This study was designed to assess the efficacy and safety of a new NK-1 receptor antagonist, netupitant, in patients with OAB. METHODS: This was a phase II, multicenter, double-blind study in which adults with OAB symptoms >6 months were randomized to receive 1 of 3 doses of netupitant (50, 100, 200 mg) or placebo once daily for 8 weeks. The primary efficacy endpoint was percentage change from baseline in average number of daily micturitions at week 8. Urinary incontinence, urge urinary incontinence (UUI), and urgency episodes were also assessed. RESULTS: The primary efficacy endpoint was similar in the treatment groups (-13.85 for placebo to -16.17 in the netupitant 200 mg group) with no statistically significant differences between netupitant and placebo. The same was true for most secondary endpoints although a significant difference for improvement in UUI episodes and a trend for the greatest decrease in urgency episodes were seen in the netupitant 100 mg group. Netupitant was well tolerated with most treatment emergent adverse events (AEs) being mild. While the overall incidence of AEs increased with netupitant dose, there was no evidence for this dose dependency based on relationship to treatment, intensity, or time to onset. CONCLUSIONS: The study failed to demonstrate superiority of netupitant versus placebo in decreasing OAB symptoms, despite a trend favoring netupitant 100 mg. There were no safety concerns with daily administration of netupitant over 8 weeks.

Effect of ghrelin and anamorelin (ONO-7643), a selective ghrelin receptor agonist, on tumor growth in a lung cancer mouse xenograft model.

PURPOSE: Anamorelin (ONO-7643) is an orally active ghrelin receptor agonist in development for non-small cell lung cancer (NSCLC)-related anorexia/cachexia. It displays both orexigenic and anabolic properties via ghrelin mimetic activity and transient increases in growth hormone (GH). However, increasing GH and insulin-like growth factor-1 in cancer patients raises concerns of potentially stimulating tumor growth. Therefore, we investigated the effect of ghrelin and anamorelin on tumor growth in a murine NSCLC xenograft model. METHODS: Female nude mice (15-21/group) with established A549 tumors were administered ghrelin (2 mg/kg i.p.), anamorelin (3, 10, or 30 mg/kg p.o.), or vehicle controls daily for 28 days. Tumor growth, food consumption, and body weight were monitored. Murine growth hormone (mGH) and murine insulin-like growth factor-1 (mIGF-1) were measured in plasma. RESULTS: Tumor growth progressed throughout the study, with no significant differences between treatment groups. Daily food consumption was also relatively unchanged, while the percentage of mean body weight gain at the end of treatment was significantly increased in animals administered 10 and 30 mg/kg compared with controls (p < 0.01). Peak mGH levels were significantly higher in ghrelin- and anamorelin-treated animals than in controls, while peak mIGF-1 levels were slightly elevated but not statistically significant. All regimens were well tolerated. CONCLUSIONS: These findings demonstrate that neither anamorelin nor ghrelin promoted tumor growth in this model, despite increased levels of mGH and a trend of increased mIGF-1. Together with anamorelin's ability to increase body weight, these results support the clinical development of ghrelin receptor agonist treatments for managing NSCLC-related anorexia/cachexia.

Total parathyroidectomy without autotransplantation in the surgical treatment of secondary hyperparathyroidism of chronic kidney disease.

BACKGROUND: Subtotal parathyroidectomy (SP) and total parathyroidectomy (TP) with autotransplantation (TPai) are the most commonly adopted operations for the treatment of secondary hyperparathyroidism (2HPT). TP without autotransplantation had previously been confined to patients with advanced dialytic vintage, not eligible for kidney transplantation. Over the years, the procedure has gained more widespread use, but there is no precise knowledge on the immediate and long-term effects. METHODS: The authors analyzed the immediate and long-term results of TP without autotransplantation, that is after the systematic removal of at least four glands in 20 patients operated for 2HPT, which were compared with results from TPai in an equal number of cases. RESULTS: An improvement of the typical clinical symptoms was found in every patient undergoing surgery, and a significant reduction in intact PTH (iPTH) serum levels was achieved. Immediate normalization of iPTH level was observed in 11/20 TP cases, hypoparathyroidism in 4/20 and persistent HPT in 5/20 cases. One year of follow-up showed a slight increase in hypoparathyroidism, with 1/20 (5%) recurrence of the disease. One-year TPai results showed a similar percentage of euparathyroidism, as well as a higher longterm recurrence rate (4/20, 20%), although values do not reach statistical significance. CONCLUSIONS: TP may still be considered the operation of choice in patients with aggressive forms of 2HPT or of advanced dialytic vintage, with no access to renal transplantation, because of its low recurrence rate (5%). Post-operative aparathyroidism is rare, while hypoparathyroidism and hypocalcemia can be well controled by medical treatment.

Integrated treatment of secondary hepatolithiasis. Case report.

Hepatolithiasis is defined as the occurrence of stones proximal to the biliary confluence and represents a prevalent disease in South East Asia being uncommon in Western countries. Biliary sepsis, hepatic abscesses and cholangiocarcinoma are considered potential complications. The Authors describe a case of a 68 years male patient affected by a left massive intrahepatic lithiasis secondary to common duct stones and associated to acute pancreatitis. The patient refused surgery and was submitted to a conservative transhepatic percutaneous treatment. After a complete removal of intrahepatic stones and a positioning of external internal biliary drainage (14F), a laparoscopic cholecistectomy was performed. The MRI control showed a complete resolution of the intrahepatic lithiasis. Conservative transhepatic percutaneous approach to hepatolithiasis represents a safe and effective treatment allowing good medium-long term results. Surgery is recommended in case of severe hepatic fibrosis or atrophy, suspected cholangiocarcinoma or multiple strictures with biliary distorsion. Integrated therapeutical protocols in referral multidisciplinary centers-offers the best long term results.

Videolaparo-assisted subtotal colectomy with cecorectal anastomosis in the treatment of chronic slow transit constipation.

Mechanical cecorectal anastomosis after subtotal colectomy, in the treatment of slow transit constipation, probably represents the most attractive surgical alternative to total colectomy and ileorectal anastomosis. In fact the operation allows better results in terms of postoperative diarrhoea, fecal incontinence and postoperative adherential syndrome. Literature data have demonstrated the feasibility of the laparoscopic approach with tipically advantages of less invasive surgery respect of parietal integrity,less postoperative pain and ileus, fewer postoperative adhesions, a reduced hospitalitation and finally, a better cosmesis. The Authors report a case of mechanical end to end cecorectal anastomosis after laparo-assisted subtotal colectomy (by four trocars) preserving superior rectal and ilecolic vessels, for the treatment of slow transit constipation in a 20 years old male patient .The reported operative approach which links tipical laparoscopic advantages to a more "safety" and "accurate" extracorporeal mechanical anastomosis.

[Surgical treatment of secondary hyperparathyroidism. Results from 47 consecutive patients]. / Trattamento chirurgico dell'iperparatiroidismo secondario. Esperienza clinica in 47 pazienti.

To date surgical treatment of secondary hyperparathyroidism (HPTs) is still controversial. Subtotal parathyroidectomy with sparing of a part of not-nodular gland and total parathyroidectomy with autotransplantation (subcutaneous or muscular) represent the most common procedures with the aim to warrant a condition of euparathyroidism. Total parathyroidectomy (or so presumed) represent an unusual therapeutic option as the risks arising from aparathyroidism and from the need of a substitutive therapy are largely known. The authors evaluate the surgical results collected from 47 consecutive patients affected by HPTs and Chronic Renal Failure (CRF) and operated on between January 1999 and January 2006. Probably, a proper indication to the type of surgical procedure could be based on the severity of the disease, on the age of the patient and on the expectation of transplant. The significant incidence of recurrence and persistent disease is due to autoimplantation or residual gland hypertrophy after subtotal parathyroidectomy, to the presence of supernumerary or ectopic glands, to cervico-mediastinic hypertrophy of cellular foci. The identification and removal of supernumerary glands, which may cause persisting hyperparathyroidism, is mandatory.

Overexpression of BCL-2 in transgenic mice protects neurons from naturally occurring cell death and experimental ischemia.

Naturally occurring cell death (NOCD) is a prominent feature of the developing nervous system. During this process, neurons express bcl-2, a major regulator of cell death whose expression may determine whether a neuron dies or survives. To gain insight into the possible role of bcl-2 during NOCD in vivo, we generated lines of transgenic mice in which neurons overexpress the human BCL-2 protein under the control of the neuron-specific enolase (NSE) or phosphoglycerate kinase (PGK) promoters. BCL-2 overexpression reduced neuronal loss during the NOCD period, which led to hypertrophy of the nervous system. For instance, the facial nucleus and the ganglion cell layer of the retina had, respectively, 40% and 50% more neurons than normal. Consistent with this finding, more axons than normal were found in the facial and optic nerves. We also tested whether neurons overexpressing BCL-2 were more resistant to permanent ischemia induced by middle cerebral artery occlusion; in transgenic mice, the volume of the brain infarction was reduced by 50% as compared with wild-type mice. These animals represent an invaluable tool for studying the effects of increased neuronal numbers on brain function as well as the mechanisms that control the survival of neurons during development and adulthood.

Site and mechanism of the colokinetic action of the ghrelin receptor agonist, HM01.

BACKGROUND: It has been recently demonstrated that the ghrelin receptor agonist, HM01, caused defecation in rats that were treated to provide a model for the constipation of Parkinson's disease. HM01 significantly increased fecal output and increased Fos activity in neurons of the hypothalamus and hindbrain, but not in the spinal defecation center. Other ghrelin agonists act on the defecation center. METHODS: Receptor pharmacology was examined in ghrelin receptor (GHSR1a) transfected cells. Anesthetized rats were used to investigate sites and mechanisms of action. KEY RESULTS: HM01 activated rat GHSR1a at nanomolar concentrations and was antagonized by the GHSR1a antagonist, YIL781. HM01, intravenous, was potent to activate propulsive colorectal contractions. This was prevented by pelvic nerve section and by intravenous YIL781, but not by spinal cord section rostral to the defecation centers. Direct intrathecal application of HM01 to the defecation center at spinal level L6-S1 initiated propulsive contractions of the colorectum. CONCLUSIONS & INFERENCES: HM01 stimulates GHSR1a receptors on neurons in the lumbosacral defecation centers to cause propulsive contractions and emptying of the colorectum. It has greater potency when given systemically, compared with other GHSR1a agonists.

Cyclodextrins in oligonucleotide delivery.

The aim of this contribution is to summarize recent findings on the potential use of cyclodextrins and their derivatives as carriers for oligonucleotide agents. Their peculiar properties could be exploited in such an emerging therapeutic area by virtue of their capability of interacting with cellular membranes, thus giving rise to improved cellular uptake. In particular, some specific derivatives could be considered as promising future excipients for the delivery of "naked" antisense and/or decoy oligonucleotides which are difficult to formulate with existing pharmaceutical excipients.

Preclinical evaluation of CHF3381 as a novel antiepileptic agent.

CHF3381 [n-(2-indanyl)-glycinamide hydrochloride] has been selected on the basis of a screening program as the compound displaying the highest anticonvulsant activity in the maximal electroshock seizure (MES) test and the best therapeutic index with reference to the rotarod test in mice and rats. In this study, the antiepileptic activity and the behavioural toxicity of CHF3381 were characterised in multiple model systems. CHF3381 effectively prevented MES-induced convulsions when administered i.p. (ED50, 24 mg/kg and 7.5 mg/kg) or p.o. (ED50, 21 mg/kg and 21 mg/kg) in both mice and rats, respectively. The time course of oral anti-MES activity in the rat was related to the brain concentration profile of unchanged CHF3381. Interestingly, the brain drug levels were about 4-5 times higher than in plasma. CHF3381 was very effective in mice against picrotoxin-, and i.c.v. N-methyl-D-aspartate (NMDA)-induced hind limb tonic extension (ED50 Approximately/=10 mg/kg), but was a weaker antagonist of 4-amynopyridine- and bicuculline-induced tonic seizures (ED50 approximately/=100 mg/kg), and ineffective against pentylentetrazole- and picrotoxin-induced clonic seizures. CHF3381 antagonised the behavioural effects and lethality of i.p. administered NMDA (ED50 = 57 mg/kg p.o.), indicating that the compound may act as a functional NMDA antagonist. In keeping with this idea, CHF3381 weakly displaced [(3)H]-TCP from binding to NMDA receptor channels (Ki, 8.8 microM). In the rat amygdala kindling model, CHF3381 was more efficient against kindling development than against kindled seizures (minimally active dose = 80 vs. 120 mg/kg i.p). Furthermore, it significantly increased the seizure threshold in kindled rats at relatively low doses (40 mg/kg i.p.). In contrast with MK-801-induced hyperactivity, CHF3381 moderately reduced the spontaneous locomotor activity in mice at anticonvulsant doses. Toxic effects on motor performance (rotarod test) were found at high doses only (TD50 approximately/= 300 mg/kg p.o., congruent with 100 mg/kg i.p. in both mice and rats). Furthermore, CHF3381 did not impair passive avoidance and Morris water maze responding in the therapeutic range of doses. Finally, the development of tolerance after repeated doses was negligible. These data indicate that CHF3381 exerts anticonvulsant and antiepileptogenic effects in various seizure models and possesses good therapeutic window, with scarce propensity to cause neurological side-effects.

Evidence against a permissive role of the metabotropic glutamate receptor 1 in acute excitotoxicity.

Excitotoxicity has been proposed to contribute to neuronal loss in a broad spectrum of neurodegenerative conditions such as ischemia, hypoglycaemic coma or cerebral trauma. Excitotoxic neuronal injury appears to be mediated mainly by the over-activation of glutamate receptors, especially N-methyl-D-aspartate receptors, with subsequent excessive Ca2+ influx. Concurrent with the activation of glutamate-gated ion channels, metabotropic glutamate receptors (mGluR), which are G-protein coupled receptors, are also expected to be activated. Excessive stimulation of phospholipase C-coupled mGluR, mGluR1 and mGluRS, has been suggested to have neurotoxic consequences. However, the contribution of mGluR activation on excitotoxicity is still unclear and controversial. Here we report that, following ischemic and excitotoxic brain injuries, inactivation of mGluR1 does not prevent excitotoxic neuronal damage. Given the evidence that agonists at this group of mGluR promoted neuronal death in cerebrocortical cultures after oxygen-glucose deprivation or after N-methyl-D-aspartate exposure, our findings suggest that mGluR-mediated excitotoxicity is unlikely associated with mGluR1 but rather with other PLC-coupled mGluR.

Pharmacological analysis of 5-hydroxytryptamine effects on electrically stimulated human isolated urinary bladder.

1. 5-Hydroxytryptamine (5-HT) is able to potentiate the contractions induced by electrical field stimulation of pieces of human isolated urinary bladder. On the basis of available selective 5-HT agonists and antagonists, we have further investigated the receptors involved and their site of action. 2. 5-HT produced a concentration-dependent increase of the contractile response to electrical field stimulation from 0.1 nM to 1 microM. At higher concentrations (up to 100 microM) the effect decreased. These activities were mimicked by a variety of 5-HT agonists, for which the following rank order of potency was found: 5-HT greater than alpha-methyl 5-HT greater than 5-methoxytryptamine greater than 5-carboxamidotryptamine greater than 2-methyl 5-HT much greater than GR 43175. In addition the gastro-prokinetics agents metoclopramide, cisapride and the 5-HT3 antagonist ICS 205-930 behaved as 5-HT agonists, their EC50 values being 2.3, 0.3, and 0.5 (microM) respectively. 3. The 5-HT potentiating effect was resistant to antagonism by ondansetron (1 microM) and cyanopindolol (1 microM), selective 5-HT3 and 5-HT1A/1B antagonists respectively. The 5-HT2 antagonists ketanserin (1 microM), spiperone (1 microM) and methysergide (1 microM) also showed a weak inhibitory activity. Methiothepin (0.1-1 microM) antagonized only the inhibitory effect of 5-HT. Metoclopramide (0.1-1 microM), cisapride (0.01-0.1 microM) and ICS 205-930 (0.3-3 microM) all produced a rightward displacement of the 5-HT response curve with concomitant reduction of the maximum response. The pA2 values calculated were 7.4, 8.5 and 7.0 respectively. The antagonism of metoclopramide was receptor specific and was not apparently related to interactions with dopaminergic activity since domperidone showed no antagonism of 5-HT, and metoclopramide, itself, did not antagonize the potentiating effect of prostaglandin F2a.4. The receptor involved in the potentiating effect of 5-HT may be located prejunctionally because 5-HT did not potentiate responses to acetylcholine (ACh) or electrical field stimulation with the parameters of direct muscle excitation. Also, since the 5-HT potentiating effect was blocked by atropine, it may be attributed to a release of ACh.5. This study suggests that in the human urinary bladder 5-HT causes two opposite effects on the contractile response to electrical field stimulation. A potentiating effect at low concentrations due to an interaction with an atypical receptor, different from the classical 5-HT1, 5-HT2 or 5-HT3 subtypes and an inhibitory effect at greater concentrations probably due to an interaction with 5-HT1-like receptors. The possibility that this atypical receptor possesses some characteristics of those found in other isolated preparations like guinea-pig ileum, rat oesophagus and mouse embryo colliculi neurones is discussed.

Evidence for the presence of both pre- and postjunctional P2-purinoceptor subtypes in human isolated urinary bladder.

1. In order to characterize P2-purinoceptor(s) in human urinary bladder the contractile effects of ATP and its slowly-hydrolyzable analogues alpha, beta-methylene ATP (alpha, beta-MeATP) and beta, gamma-methylene ATP (beta, gamma-MeATP) were investigated on human detrusor strips taken from patients undergoing cystectomy for bladder carcinoma. 2. Serial concentration-response curves (SCRC) for ATP, alpha, beta-MeATP and beta, gamma-MeATP were constructed with an interval of 25 min between two successive doses to avoid tachyphylaxis. ATP (10 microM-10 mM) induced a phasic contraction, which was very rapid in onset. The dose-response curve to ATP appeared not to be monophasic: at the lower concentrations (10-300 microM) the curve was shallow, whilst at high concentrations (1-10 mM) the curve was steeper. The magnitude of the response obtained at the highest concentration tested (10 mM) was only 21.1 +/- 2.8% (mean +/- s.e. mean; n = 4) of the KCl (100 mM)-induced contraction. 3. alpha, beta-MeATP (0.3 microM-1 mM) and beta, gamma-MeATP (10 microM-1 mM) elicited a phasic contraction with a time course similar to that exhibited by ATP. The magnitude of the response obtained at the highest concentration tested (1 mM) was 70.3 +/- 6.3% for alpha, beta-MeATP (n = 10) and 27.9 +/- 4.5% for beta, gamma-MeATP (n = 8) of KCl (100 mM)-induced contraction. The rank order of potency was alpha, beta-MeATP > beta, gamma-MeATP > ATP. A plateau of response could not be achieved by any of these agonists. 4. The P2-purinoceptor antagonist, suramin (10-300 microM), dose-dependently antagonized only the lower part of alpha,beta-MeATP dose-response curve. Data were analysed in terms of dose-ratio estimated at two levels of response (10% and 35% of KC1 100 mM-induced contraction). At 10% of KCl response the Schild plot slope was 0.98 and the estimated pKB was 5.85, whereas using the dose-ratio at the 35% level of the KCl response, the Schild plot was not linear suggesting an interaction of alpha,beta-MeATP with a heterogeneous receptor population.5. The putative P2-purinoceptor antagonist, Coomassie Brilliant Blue G (CB-G) at 0.3 and 1 l micro M(n = 5), shifted to the left the alpha,beta-MeATP SCRC. The response at the highest concentration of agonist was potentiated, being equal to 78.8 +/- 11.7% of the KCl (100 mM) response (n = 5). CB-G at 0.3 microM also shifted to the left the beta,upsilon-MeATP SCRC and significantly potentiated the response at 1 mM up to 46.3 +/- 5.6% of KCl 100 mM response (n = 4).6. Pretreatment with terodotoxin (TTX) at 1 microM shifted to the left the alpha,beta-MeATP SCRC but the response to the highest concentration of the agonist was not potentiated, being 73.6 +/- 9.9% of the KCl(100 mM) response (n = 5). TTX (1 micro M) shifted to the left the beta,upsilon-MeATP SCRC and significantly potentiated the response at 1 mM (61.6 +/- 3.1% of KCl response; n = 4).7. The NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) at 100 micro M did not modify the SCRC to either alpha, beta or beta,upsilon-MeATP.8. We conclude that in human detrusor muscle there is a heterogeneity of purinoceptors. The complex antagonism exhibited by suramin suggests the presence not only of Ph-purinoceptors but also of another contractile P2-purinoceptor subtype insensitive to suramin. Moreover, the activity of CB-G and TTX seems to support the existence of a prejunctional P2-purinoceptor subtype inducing the release of one or more inhibitor neurotransmitters.

Pharmacological characterization of thromboxane and prostanoid receptors in human isolated urinary bladder.

1. Cumulative concentration-response curves (CRC) to prostaglandin E1 (PGE1), PGE2, PGD2 and PGF2alpha (0.01-30 microM) and to the thromboxane A2 (TXA2) receptor agonist U-46619 (0.01-30 microM) were constructed in human isolated detrusor muscle strips both in basal conditions and during electrical field stimulation. 2. All the agonists tested contracted the detrusor muscle. The rank order of agonist potency was: PGF2alpha > U-46619 > PGE2 whereas weak contractile responses were obtained with PGD2 and PGE1. Any of the agonists tested was able to induce a clear plateau of response even at 30 microM. 3. The selective TXA2 antagonist, GR 32191B (vapiprost), antagonized U-46619-induced contractions with an apparent pK(B) value of 8.27+/-0.12 (n = 4 for each antagonist concentration). GR 32191B (0.3 microM) did not antagonize the contractile responses to PGF2alpha and it was a non-surmountable antagonist of PGE2 (apparent pK(B) of 7.09+/-0.04; n = 5). The EP receptor antagonist AH 6809 at 10 microM shifted to the right the CRC to U-46619 (apparent pK(B) value of 5.88+/-0.04; n = 4). 4. Electrical field stimulation (20 Hz, 70 V, pulse width 0.1 ms, trains of 5 s every 60 s) elicited contractions fully sensitive to TTX (0.3 microM) and atropine (1 microM). U-46619 (0.01-3 microM) potentiated the twitch contraction in a dose-dependent manner and this effect was competitively antagonized by GR 32191B with an estimated pK(B) of 8.54+/-0.14 (n = 4 for each antagonist concentration). PGF2alpha in the range 0.01-10 microM (n = 7), but not PGE2 and PGE1 (n = 3 for each), also potentiated the twitch contraction of detrusor muscle strips (23.5+/-0.3% of KCl 100 mM-induced contraction) but this potentiation was unaffected by 0.3 microM GR 32191B (n = 5). 5. Cumulative additions of U-46619 (0.01-30 microM) were without effect on contractions induced by direct smooth muscle excitation (20 Hz, 40 V, 6 ms pulse width, trains of 2 s every 60 s, in the presence of TTX 1 microM; n = 3). Moreover, pretreatment of the tissue with 0.3 microM U-46619 did not potentiate the smooth muscle response to 7 microM bethanecol (n = 2). 6. We concluded that TXA2 can induce direct contraction of human isolated urinary bladder through the classical TXA2 receptor. Prostanoid receptors, fully activated by PGE2 and PGF2alpha are also present. All these receptors are probably located post-junctionally. The rank order of agonist potency and the fact that GR 32191B, but not AH6809, antagonized responses to PGE2 seem to indicate the presence of a new EP receptor subtype. Moreover, we suggest the presence of prejunctional TXA2 and FP receptors, potentiating acetylcholine release from cholinergic nerve terminals.

Analysis of the CCKB receptor antagonism of virginiamycin in guinea-pig ileum longitudinal myenteric plexus.

1. Virginiamycin, a macrolide reported to bind selectively to CCKB/gastrin receptors has been studied in a functional test, namely cholecystokinin-induced contraction of guinea-pig ileum myenteric plexus (LMMP). 2. Virginiamycin (1-10 microM) antagonized the selective CCKB agonist cholecystokinin tetrapeptide (CCK-4). The antagonism appeared not to be competitive as the highest concentration (10 microM) caused a reduction of its maximal effect. An apparent pA2 of 6.64 +/- 0.06 (s.e.) could be estimated if this depression was ignored. The selective CCKB antagonist, L-365,260 (0.01-0.3 microM) antagonized competitively the CCK-4 induced contraction and a pKB of 8.60 +/- 0.16 (s.e.) was estimated. 3. The combined dose-ratio analysis for virginiamycin, tested at 3 and 10 microM in association with 0.03 and 0.1 microM L-365,260, respectively, resulted in observed log dose-ratios of 1.39 and 1.53. That was consistent with both antagonists acting on the same receptor in LMMP. 4. These data, represent the first evidence of the antagonism of virginiamycin in a functional assay and they support the hypothesis of homogeneity between CCKB receptors in the CNS and in peripheral tissues.

Further studies on the effects of selective neurokinin agonists upon the activation of micturition reflex in rats. Evidence for a dual NK-1 receptor mediated excitatory and inhibitory activity.

The ability of SP and some selective agonists for NK-1, NK-2 and NK-3 receptor subtypes to interfere with the micturition reflex after intra-arterial (i.a.) or intracerebroventricular (i.c.v.) administration was investigated in the urethane anaesthetized rat. When administered i.a. SP, the selective NK-1 agonist GR 73632 and the selective NK-2 agonists GR 64349 were equipotent to activate micturition reflex, both the tonic or rhythmic bladder contractions. GR 73632 but not GR 64349-induced activation of micturition reflex was antagonized in a dose-dependent manner by the selective NK-1 antagonist GR 82334. After i.c.v. administration SP, GR 73632 and the selective NK-1 agonist [Sar9,Met(0(2))11]-SP but not GR 64349 inhibited saline-induced activation of rhythmic bladder contractions; the order of potency was GR 73632 > [Sar9,Met(0(2))11]SP >> SP. Also the inhibitory effect of GR 73632 was dose-dependently affected by GR 82334. In the two models the selective NK-3 agonist senktide both after i.a. or i.c.v. administration induced neither excitatory or inhibitory activity. These findings suggest that neurokinins activate at the peripheral level the micturition reflex by an interaction at NK-1 and NK-2 receptor subtypes. In addition, NK-1 receptors appear to modulate, at the central level, the inhibition of the micturition reflex.

Antispasmodic effects of flavoxate, MFCA, and REC 15/2053 on smooth muscle of human prostate and urinary bladder.

The antispasmodic effects of the flavone compounds flavoxate hydrochloride, 3-methylflavone carboxylic acid (MFCA), and REC 15/2053 (and in the case of the detrusor, oxybutynin), on the human detrusor, prostatic adenoma, prostatic capsule, and bladder neck, were studied by the in vitro isometric method. All the compounds inhibited, in different orders of potency, potassium-induced contractions of the tissues. Flavoxate showed a slightly greater activity than the other two compounds in the prostatic and bladder neck tissues. However, REC 15/2053 displayed greater activity in the detrusor than in the other tissues. The relaxant effect on the prostatic tissues suggests a potential use for these compounds in benign prostatic obstruction.

In vivo neurochemical effects of the acetylcholinesterase inhibitor ENA713 in rat hippocampus.

Oral ENA713 (0.5, 1.5 and 4.5 mg/kg), an acetylcholinesterase inhibitor (AChEI), dose-dependently enhanced extracellular acetylcholine concentrations in the hippocampus of freely moving rats. This effect was paralleled by changes in both noradrenergic and dopaminergic transmission. In particular, ENA713 significantly decreased noradrenaline concentrations, whereas it significantly increased homovanillic acid levels, without affecting dopamine concentrations. Neither serotonin nor gamma-aminobutyric acid levels were modified by ENA713. These findings extend the neurochemical profile of ENA713 and suggest that it could be useful for the treatment of Alzheimer-type dementia which is associated with multiple neurotransmitter abnormalities in the brain.

Effects of ENA713 and CHF2819, two anti-Alzheimer's disease drugs, on rat amino acid levels.

The effects of oral ENA713 and CHF2819 (0.5, 1.5 and 4.5 mg/kg), two novel acetylcholinesterase inhibitors, on extracellular concentrations of amino acids in rat hippocampus, were evaluated using in vivo microdialysis. ENA713, at 4.5 mg/kg, but not CHF2819, significantly decreased glutamate, taurine, arginine and citrulline levels, without affecting aspartate concentrations. These results suggest that the modulation of amino acidergic transmission could represent an additional mechanism of action in Alzheimer's disease for some acetylcholinesterase inhibitors.

The neuroprotective activity of the glycine receptor antagonist GV150526: an in vivo study by magnetic resonance imaging.

The neuroprotective activity of GV150526 (3-[2-(Phenylaminocarbonyl)ethenyl]-4,6-dichloroindole-2-carboxylic acid sodium salt), a selective glycine receptor antagonist of the NMDA receptor, has been evaluated by magnetic resonance imaging (MRI) in a rat model of middle cerebral artery occlusion. The aim of the work was to evaluate, using an in vivo method, whether GV150526 was able to reduce the extent of ischemic brain damage when administered both before and after (6 h) middle cerebral artery occlusion. GV150526 was administered at a dose of 3 mg/kg i.v. T2-weighted (T2W) and diffusion weighted (DW) images were acquired at 6, 24 and 144 h after the establishment of the cerebral ischemia. Substantial neuroprotection was demonstrated at all investigated time points when GV150526 was administered before the ischemic insult. The ischemic volume was reduced by 84% and 72%, compared to control values, when measured from T2W and DW images, acquired 24 h after middle cerebral artery occlusion. Administration of the same dose of GV150526, 6 h post-ischemia, also resulted in a significant (p < 0.05) neuroprotection. The ischemic volume was reduced by 48% from control values when measured from T2W images and by 45% when measured from DW images. No significant difference was found between volumes of brain ischemia obtained by either MRI or triphenyltetrazolium chloride staining. These data confirm the potential neuroprotective activity of the glycine receptor antagonist GV150526 when administered either before or up to 6 h after ischemia.