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.

New ghrelin agonist, HM01 alleviates constipation and L-dopa-delayed gastric emptying in 6-hydroxydopamine rat model of Parkinson's disease.

BACKGROUND: Constipation and L-dopa-induced gastric dysmotility are common gastrointestinal (GI) symptoms in Parkinson's disease (PD). We investigated the novel ghrelin agonist, HM01 influence on GI motor dysfunctions in 6-hydroxydopamine (6-OHDA) rats. METHODS: HM01 pharmacological profiles were determined in vitro and in vivo in rats. We assessed changes in fecal output and water content, and gastric emptying (GE) in 6-OHDA rats treated with orogastric (og) HM01 and L-dopa/carbidopa (LD/CD, 20/2 mg/kg). Fos immunoreactivity (ir) cells in specific brain and lumbosacral spinal cord were quantified. KEY RESULTS: HM01 displayed a high binding affinity to ghrelin receptor (Ki: 1.42 ± 0.36 nM), 4.3 ± 1.0 h half-life and high brain/plasma ratio. 6-OHDA rats had reduced daily fecal output (22%) and water intake (23%) compared to controls. HM01 (3 and 10 mg/kg) similarly reversed the decreased 4-h fecal weight and water content in 6-OHDA rats. Basal GE was not modified in 6-OHDA rats, however, LD/CD (once or daily for 8 days) delayed GE in 6-OHDA and control rats that was prevented by HM01 (3 mg/kg acute or daily before LD/CD). HM01 increased Fos-ir cell number in the area postrema, arcuate nucleus, nucleus tractus solitarius, and lumbosacral intermediolateral column of 6-OHDA rats where 6-OHDA had a lowering effect compared to controls. CONCLUSIONS & INFERENCES: 6-OHDA rats display constipation- and adipsia-like features of PD and L-dopa-inhibited GE. The new orally active ghrelin agonist, HM01 crosses the blood-brain barrier and alleviates these alterations suggesting a potential benefit for PD with GI disorders.

Long-term function of parathyroid subcutaneous autoimplantation after presumed total parathyroidectomy in the treatment of secondary hyperparathyroidism. A clinical retrospective study.

INTRODUCTION: Parathyroidectomy (PTx) is recommended in patients affected by secondary hyperparathyroidism (2HPT) of chronic kidney disease-mineral bone disorders (CKD-MBD), resistant to medical treatment. Analyzing total parathyroidectomy with muscular or subcutaneous autoimplantation (TPai) outcomes in hemodialysis (HD) 2HPT patients, and monitoring intact parathyroid hormone (iPTH) levels, we evaluated long-term functional results of subcutaneous parathyroid glandular tissue autoimplantation. METHODS: 40 HD 2HPT patients, resistant to medical treatment, and awaiting for renal transplantation, underwent total parathyroidectomy with subcutaneous autoimplantation of 9-12 fragments of not nodular hyperplasia parathyroid tissue in not dominant forearm. iPTH were analyzed 24 h, and 3-6-12-24 months after surgery. The 1.08-6.99 pmol/L range was taken as reference of normal iPTH level based on which eu- (1.08-6.99), hypo- (<1.08), aparathyroidism (0) and persistence or relapse (>6.99) of disease were determined. RESULTS: In every case PTai determined an extraordinary improvement of quality of life, associated with a notable reduction of iPTH serum level. Immediate normalization of iPTH was achieved in 50% of cases; hypoparathyroidism in 25% of cases and persistence of disease in 25% were observed. Long term follow-up showed a reduction of hypoparathyroidism and an increase of relapse rate up to 20%. Grafting resection was never performed. DISCUSSION: Subcutaneous autotrasplantation is a very simple and fast surgical technique. Nevertheless, similar success and recurrence rates were reported following muscular or subcutaneous grafting, as confirmed in our experience. CONCLUSIONS: Subcutaneous grafting was effective as muscular implantation, with comparable functional results, but avoiding its potential complications.

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.

Evaluation of the 'putative' role of intraoperative intact parathyroid hormone assay during parathyroidectomy for secondary hyperparathyroidism. A retrospective study on 35 consecutive patients: intraoperative iPTH assay during parathyroidectomy.

In the surgical treatment of secondary hyperparathyroidism (2HPT) of chronic kidney disease (CKD), a parathyroidectomy (PTx) of 4 glands can only be presumed as 'total', and indications for autoimplantation are complex. Intraoperative rapid parathyroid hormone assay could be useful to predict a radical resection. We evaluated iPTH levels 20 min and 24 h after a 4-gland PTx in 35 patients to determine the predictive value of intraoperative iPTH assay. We analysed retrospectively 35 patients affected by 2HPT of CKD, 13 undergoing total parathyroidectomy (TP) and 22 TP + autoimplantation (TPai), after removing 4 glands in 33 cases and 5 glands in 2. Intact PTH assays were acquired after 40 min before induction of anaesthesia, after removing both ipselateral glands, at 20 min after surgery and on postoperative day 1. 20 min after 4-gland PTx, a decrease of iPTH levels >80 % of the preoperative value was observed in 27 of 35 cases (77.1 %) and <80 % in 8 of 35 cases (22.8 %). In 6 of these 8 patients, iPTH levels were within the normal range 24 h after surgery. Although the intraoperative iPTH assays are of interest in the treatment of 2HPT, the predictive value of this method is not entirely satisfactory. In fact, a 4-gland PTx ensures euparathyroidism in most cases, even when intraoperative iPTH assays are not trustworthy; however, intraoperative iPTH assay, although not a perfect 'tool', is a proved aid for the surgeon in making his decision.

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.

[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.

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.

Characterization of the effect of ganstigmine (CHF2819) on amyloid precursor protein metabolism in SH-SY5Y neuroblastoma cells.

We have investigated the effect of ganstigmine (CHF2819), a novel geneserine derived acetylcholinesterase (AChE) inhibitor, on the expression and metabolism of the amyloid precursor protein (APP) in neuroblastoma cell line SH-SY5Y. The rationale was based on the suggestion that cholinergic activity may also be involved in the regulation of APP metabolism. We studied the acute effect on APP metabolism following the secretion of sAPPalpha in the conditioned medium of cells. Following short term treatment (2h), ganstigmine promoted a slight increase in the release of sAPPalpha, the maximal effect approaching on average 1.5 fold baseline value. The data obtained in the long term experiments demonstrate that continuous inhibition of AchE obtained with 100 nM ganstigmine following an exposure of 24 hours did not influence APP isoforms expression. However, the compound appeared to increase the constitutive release of sAPPalpha, with a mechanism that is derived from an indirect cholinergic stimulation.

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.

Anticonvulsant preclinical profile of CHF 3381: dopaminergic and glutamatergic mechanisms.

Following intraperitoneal or oral administrations, CHF 3381 ([n-(2-indanyl)-glycinamide hydrochloride]) protected rats against maximal electroshock (MES) test seizures. As glutamatergic pathways play a pivotal role in epilepsy, to better characterize the molecular mechanisms of action of CHF 3381, the drug effects on the binding of the excitatory amino acid antagonist [3H]-MK-801 in the presence of n-methyl-D-aspartate (NMDA), spermidine, or the combination of both ligands, were studied. CHF 3381 inhibited the [3H]-MK-801 specific binding in a noncompetitive fashion in respect to NMDA and polyamines recognition sites. CHF 3381 failed to change the kinetic characteristic of glycine B receptors labeled with [3H]-glycine; in contrast, it significantly increased K(d) values when the receptors were labeled with the more specific compound [3H]-MDL 105,519. CHF 3381 antagonized dopamine (DA)-induced behavioral responses and inhibited, in a glycine-dependent manner, the NMDA-induced [3H]-DA release from rat striatal slices, but it failed to change either the kinetic characteristics of D1, D2, or D3 receptors in synaptic plasma membranes (SPM) or the [3H]-DA uptake from striatal synaptosomes. Moreover, in primary cell cultures of cortical neurons, this drug exhibited glycine-independent neuroprotective effects against glutamate-induced excitotoxicity. It is concluded that this compound could have a potential use in several disease states where a pathological high level of NMDA receptor activation is thought to occur.

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.

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.

Biochemical and neurobehavioral profile of CHF2819, a novel, orally active acetylcholinesterase inhibitor for Alzheimer's disease.

1,2,3,3a,8,8a-Hexahydro-1,3a,8-trimethylpyrrolo¿2,3-bindol-5-ol 2-ethylphenylcarbamate N-oxide hydrochloride (3aS-cis) (CHF2819) is a novel acetylcholinesterase inhibitor that produces central cholinergic stimulation after oral administration in rats. In vivo studies show that CHF2819 (0.5, 1.5, and 4.5 mg/kg p.o.) significantly increases acetylcholine levels in young adult rat hippocampus in a dose-dependent manner. Moreover, aged animals, which show a significant decrease in basal acetylcholine levels with respect to young adult rats, also exhibit a marked increase in the hippocampal concentrations of this neurotransmitter after the administration of CHF2819. This compound (1.5 mg/kg p.o.) significantly attenuates scopolamine-induced amnesia in a passive avoidance task. Furthermore, CHF2819 induces a significant decrease in dopamine levels and a significant elevation of extracellular concentrations of 5-hydroxytryptamine, whereas it does not modify norepinephrine and gamma-aminobutyric acid levels in the hippocampus of young adult rats. Functional observational battery screening demonstrates that CHF2819 (1.5 and 4.5 mg/kg p.o.) does not affect activity, excitability, autonomic, neuromuscular, and sensorimotor domains, as well as physiological end points (body weight and temperature). However, this compound induces involuntary motor movements (ranging from mild tremors to myoclonic jerks) in a dose-dependent manner. These findings suggest that the anti-amnestic properties of CHF2819, together with its stimulatory effect on cholinergic and serotonergic functions, might have a therapeutic potential mainly for the symptomatic treatment of Alzheimer's disease patients in which the cognitive impairment is accompanied by a depressive syndrome.

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.

4-Aminopyridine derivatives with antiamnesic activity.

Acetylcholine (Ach) enhancement, useful in the treatment of Alzheimer's disease (AD), may be obtained by means of ion channel modulators such as 4-aminopyridine (4-AP). 4-AP is also the central ring of tacrine, the first drug approved for the treatment of AD. The synthesis and pharmacological activity of three 4-AP derivatives, prepared with the aim of improving their antiamnesic activity, is here described. In two of these compounds 4-AP is connected to 4-aminobutyric acid (GABA), whereas in the third it is connected to 2-indolinone, i.e., the skeleton of linopirdine, another Ach enhancing agent. The new compounds showed potent antiamnesic activity in comparison with piracetam.

Involvement of spinal NK1 and opioids receptors in modulating the inhibitory effect of capsaicin on micturition reflex in the acute spinalized guinea pig.

PURPOSE: The aim of this work was to study the role of capsaicin-sensitive afferent fibers in modulating the micturition reflex at spinal level in urethane-anesthetized guinea pigs after spinal cord transection at level T3-T4. MATERIALS AND METHODS: The intravesical effect of capsaicin was investigated in a series of cystometrograms performed in intact and spinalized animals. RESULTS: In both intact and spinalized animals capsaicin, at 30 microM, induced a significant increase of volume threshold only, whereas at 100 microM it induced a complete inhibition of the spinal micturition reflex in 60% and 85% of the animals tested, respectively. This capsaicin inhibitory effect (CIE) was unaffected by intravenous phentolamine and propranolol (0.5 and 1 mg./kg., respectively), indomethacin at 100 nmoles intrathecally (i.t.), the CGRP receptor antagonist hCGRP8-37 (3 nmoles i.t.) and the NK2 receptor selective antagonist GR 94800 (1 nmol. i.t.). However, both naloxone (30 microg. i.t.) and the NK1 antagonist GR 82334 (10 to 20 nmoles i.t.) prevented CIE in the majority of spinalized animals. CONCLUSIONS: These results suggest that CIE could be mediated by enkephalines released by dorsal root ganglion neurons through substance P release and subsequent activation of NK1 receptors in acutely spinalized guinea pigs.