Longitudinal Cognitive Decline in Patients With Mild Cognitive Impairment or Dementia Due to Alzheimer's Disease

Sensitive cognitive assessments accurately detect and track cognitive decline in Alzheimer's disease. The Cogstate battery was used to measure cognitive change in cognitively normal participants and in individuals with mild cognitive impairment and mild Alzheimer's disease enrolled in the Australian Imaging, Biomarker and Lifestyle Rate of Change Substudy. Over 18 months, verbal episodic memory performance declined for mild cognitive impairment and mild Alzeheimer's disease groups when compared to cognitively normal participants. Frequent assessments of episodic memory may facilitate early detection of cognitive decline due to Alzheimer's disease.

Why genes are like lemons

In the last few years, the lack of a unitary notion of gene across biological sciences has troubled the philosophy of biology community. However, the debate on this concept has remained largely historical or focused on particular cases presented by the scientific empirical advancements. Moreover, in the literature there are no explicit and reasonable arguments about why a philosophical clarification of the concept of gene is needed. In our paper, we claim that a philosophical clarification of the concept of gene does not contribute to biology. Unlike the question, for example, "What is a biological function?", we argue that the question "What is a gene?" could be answered by means of empirical research, in the sense that biologists' labour is enough to shed light on it.

Differential effects of the CRF-R1 antagonist GSK876008 on fear-potentiated, light- and CRF-enhanced startle suggest preferential involvement in sustained vs phasic threat responses

The amplitude of the acoustic startle response is increased when elicited in the presence of brief cues that predict shock (fear-potentiated startle) and also when elicited during sustained exposure to bright light (light-enhanced startle). Although both effects are thought to reflect fear or anxiety, their neuroanatomical substrates differ. Although fear-potentiated startle is disrupted by reversible inactivation of the central nucleus of the amygdala (CeA) but not the closely related bed nucleus of the stria terminalis (BNST), light-enhanced startle is disrupted by BNST inactivation but not by CeA inactivation. Intraventricular infusions of corticotropin-releasing factor (CRF) also increase startle (CRF-enhanced startle) and this effect is mediated by CRF receptors within the BNST, with no involvement of the CeA. Together, these observations suggest that CeA- and BNST-dependent fear and anxiety may be differentially sensitive to CRF receptor blockade. We tested this by orally administering the novel, potent, and selective CRF-R1 antagonist GSK876008 to rats before CRF-enhanced, light-enhanced, or fear-potentiated startle testing. GSK876008 disrupted CRF-enhanced startle with a linear dose-response curve, and light-enhanced startle with a U-shaped dose-response curve, but did not disrupt fear-potentiated startle to a visual stimulus at any dose tested, and even augmented the response in some animals. GSK876008 also disrupted shock-related 'baseline' startle increases, which may have reflected context conditioning (shown elsewhere to also be BNST-dependent). Overall, these results suggest that short-duration CeA-dependent threat responses can be pharmacologically dissociated from longer duration BNST-dependent responses in terms of their sensitivity to CRF1 receptor antagonists.

3-[(±)-2-Carboxypiperazin-4-yl]propyl-1-Phosphonic Acid Recognizes Two N-Methyl-D-Aspartate Binding Sites in Rat Cerebral Cortex Membranes

Binding of 3-[(+-)-2-carboxypiperazin-4-yl][3H]-propyl-1-phosphonic acid ([3H]CPP), a competitive inhibitor of N-methyl-D-aspartate (NMDA), has been studied in synaptic plasma membranes from rat cerebral cortex. Computer analysis of saturation and homologous displacement isotherms deriving from these plasma membranes indicated the existence of two binding sites: a specific, saturable, high-affinity binding site with a pKD value of 7.53 +/- 0.03 (29.5 nM) and a maximum binding value (Bmax) of 2.25 +/- 0.36 pmol/mg of protein, and a low-affinity site with a KD of approximately 600 nM and a Bmax of 7.0 pmol/mg of protein. It is argued that, in the light of current literature evidence, the low-affinity binding site may represent an agonist-dependent receptor, linked to physiological processes such as neurotransmitter release and channel regulation, whereas the high-affinity binding site may be linked to an antagonist-preferred receptor, for which no function has yet been reported.

The selective glycine antagonist gavestinel lacks phencyclidine-like behavioral effects

Gavestinel [GV150526A; ( E)-3[(phenylcarbamoil)ethenyl]-4,6-dichloroindole-2-carboxylic acid sodium salt] is a selective antagonist at the strychnine-insensitive glycine site of the -methyl-D-aspartate (NMDA) receptor. It was tested for its ability to substitute for phencyclidine (PCP) in rats and rhesus monkeys trained to discriminate PCP from saline, under a two-lever fixed-ratio (FR) food reinforcement schedule, and for its ability to maintain responding in rhesus monkeys trained to self-administer PCP under a FR reinforcement schedule. No PCP-lever responding was observed after gavestinel (1-56 mg/kg i.p.) administration to rats discriminating PCP (2.0 mg/kg i.p.) from saline. The highest dose of gavestinel (100 mg/kg i.p.) tested eliminated responding. Likewise, no PCP-lever responding was observed after gavestinel (1-30 mg/kg s.c.) administration to rhesus monkeys discriminating PCP (0.08 or 0.1 mg/kg i.m.) from saline; the highest dose of gavestinel (30 mg/kg s.c.) tested reduced response rates to approximately 50% of those observed after its vehicle ( -cyclodextrin in 0.9% saline). Gavestinel (0.1-1 mg/kg per i.v. infusion) was not self-administered by rhesus monkeys that reliably self-administered PCP (0.0056 or 0.01 mg/kg per i.v. infusion). Infusion rates at the highest dose were typically lower than those for vehicle or saline, suggesting behavioral activity. Together, these results suggest that at behaviorally active doses gavestinel is not PCP-like and is likely to have low abuse liability.

The continuing evolution of the drug discovery process in the pharmaceutical industry

Many early discoveries in the pharmaceutical industry were through serendipity. Later, targets were mainly identified in animals and systematically exploited through the identification of potent and selective molecules. A disease association was normally obtained through the clinical testing of candidate molecules in patients. The technological advances in the last few years offer the possibility of knowing more about the disease, and this is driving the industry towards a disease-based approach where understanding the disease becomes central to the process. This is now possible thanks to the recent explosion in molecular and cellular biology, together with the application of genetics and genomics. New screening technologies have also revolutionized the identification of chemical leads. Now, high throughput screening allows a wide chemical diversity to be applied in order to obtain tractable leads, which can then be optimized by the medicinal chemist. It is envisaged that these trends of continuously searching for process improvement will continue, being driven by the need to find medicines that add value in treating unmet medical need.

Synthesis and SAR of new 5-phenyl-3-ureido-1,5-benzodiazepines as cholecystokinin-B receptor antagonists

A series of 5-phenyl-3-ureidobenzodiazepine-2,4-diones was synthesized and evaluated as cholecystokinin-B (CCK-B) receptor antagonists. Structure-activity relationship (SAR) studies revealed the importance of the N-1 substituent for potent and selective CCK-B affinity. Addition of substituents at the urea side chain provided in some cases more potent compounds. Moreover the introduction of bulky substituents such as adamantylmethyl at N-1 and resolution of the racemic ureas resulted in our lead compound GV150013.

Involvement of cholecystokinin within craving for cocaine: role of cholecystokinin receptor ligands

In the brain, cholecystokinin (CCK) has been described to act as a central neurotransmitter or neuromodulator involved in functions such as food consumption, stress and anxiety. Recently, the CCK system has been involved in drug dependence phenomena and proposed to be correlated to a putative state of 'drug preferring' phenotype within free choice tests. CCK exerts its action in the CNS through at least two different G-protein coupled high affinity receptors, CCK1 and CCK2. Various selective CCK receptor agonists and antagonists have been synthesised. In particular, L-364,718 has been demonstrated to be a potent and selective CCK1 receptor antagonist, whereas L-365,260 is a potent and selective CCK2 receptor antagonist. More recently, GV150013 has been reported to be a highly selective CCK2 receptor antagonist. This paper reviews the putative role of the CCK system within drug dependence phenomena. In particular, it analyses the relationship between central CCK activity and the exhibition of spontaneous preference for drugs of abuse, such as cocaine or alcohol. The potential therapeutic role for CCK receptor antagonists is also discussed.

[Intestinal preparation with an osmotic solution for edema with double contrast media]

PURPOSE

To evaluate the most effective way of cleansing the colon lumen for double contrast colon enema with a single preparation at osmotic effect.

MATERIAL AND METHODS

We examined 80 patients (age range: 29-84 years) and divided them into two groups. Group 1: patients (no. 41) were prepared with the traditional method consisting of a residue-free diet in the three days before the examination followed by the administration of a sennoside-based laxative the morning of the day before and a dose of magnesium sulphate in the afternoon, after the Genoa School method. Group 2: patients (no. 39) were prepared with a Phospholax solution according to the following administration schedule: one dose in the evening two days before the examination and four doses the day before, that is two in the afternoon and two in the evening, followed by abundant hydratation. The examination was performed in a double blind fashion and graded as follows: excellent, good, sufficient, poor. The statistical analysis of all data was performed with Student's t-test and the chi-square test.

RESULTS

We obtained better results with the new protocol than with the traditional one, where some patients discontinued the preparation because of intolerance (nausea, abdominal pain and swelling). In addition, more fecal residues were found in the colon with the first preparation, which however provided better contrast agent coating than the new protocol. The second preparation provided better mucosal cleansing, with more cases graded as excellent-good, and there were no cases of poor coating or electrolyte disturbances.

DISCUSSION AND CONCLUSIONS

Intestinal preparation with Phospholax was better than the conventional method relative to compliance, intestinal cleansing and side-effects (in both the latter two cases, the difference is statistically significant, p < 0.01). In conclusion the new protocol is a possible alternative to the traditional method thanks to its ease of preparation and effective results.

Potent antihyperalgesic activity without tolerance produced by glycine site antagonist of N-methyl-D-aspartate receptor GV196771A

Central sensitization is a condition of enhanced excitability of spinal cord neurons that contributes to the exaggerated pain sensation associated with chronic tissue or nerve injury. N-methyl-D-aspartate (NMDA) receptors are thought to play a key role in central sensitization. We have tested this hypothesis by characterizing in vitro and in vivo a novel antagonist of the NMDA receptor acting on its glycine site, GV196771A. GV196771A exhibited an elevated affinity for the NMDA glycine binding site in rat cerebral cortex membranes (pKi = 7.56). Moreover, GV196771A competitively and potently antagonized the activation of NMDA receptors produced by glycine in the presence of NMDA in primary cultures of cortical, spinal, and hippocampal neurons (pKB = 7.46, 8. 04, and 7.86, respectively). In isolated baby rat spinal cords, 10 microM GV196771A depressed wind-up, an electrical correlate of central sensitization. The antihyperalgesic properties of GV196771A were studied in a model of chronic constriction injury (CCI) of the rat sciatic nerve and in the mice formalin test. In the CCI model GV196771A (3 mg/kg twice a day p.o.), administered before and then for 10 days after nerve ligature, blocked the development of thermal hyperalgesia. Moreover, GV196771A (1-10 mg/kg p.o.) reversed the hyperalgesia when tested after the establishment of the CCI-induced hyperalgesia. In the formalin test GV196771A (0.1-10 mg/kg p.o.) dose-dependently reduced the duration of the licking time of the late phase. These antihyperalgesic properties were not accompanied by development of tolerance. These observations strengthen the view that NMDA receptors play a key role in the events underlying plastic phenomena, including hyperalgesia. Moreover, antagonists of the NMDA glycine site receptor could represent a new analgesic class, effective in conditions not sensitive to classical opioids.

Spontaneous preference for ethanol in naive rats is influenced by cholecystokinin A receptor antagonism

Naive adult male Wistar rats free to choose between water or 10% ethanol (v/v) spontaneously became water-preferring (WP) rats, as they drank mainly water (approximately 35 ml per day), or alcohol-drinking (ED) rats, as they also drank a significant amount of ethanol (approximately 14 ml per day). The selective CCKA receptor antagonist L-364,718 at doses selective for the CCKA receptor (5 micrograms/kg, IP) halved the consumption of alcohol of the ED rats without modifying their total liquid in-take. In contrast, the CCKB antagonists L-365,260 or GV150013 were without effect when used at doses selective for the CCKB receptor. These data indicate that the CCK system could be involved in the modulation of alcohol intake. In particular, they suggest that CCKA receptors could play a role in the ethanol preference.

Substituted indole-2-carboxylates as in vivo potent antagonists acting as the strychnine-insensitive glycine binding site

A series of indole-2-carboxylates bearing suitable chains at the C-3 position of the indole nucleus was synthesized and evaluated in terms of in vitro affinity using [3H]glycine binding assay and in vivo potency by inhibition of convulsions induced by N-methyl-D-aspartate (NMDA) in mice. 3-[2-[(Phenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxyl ic acid (8) was an antagonist at the strychnine-insensitive glycine binding site (noncompetitive inhibition of the binding of [3H]TCP, pA2 = 8.1) displaying nanomolar affinity for the glycine binding site (pKi = 8.5), coupled with high glutamate receptor selectivity (> 1000-fold relative to the affinity at the NMDA, AMPA, and kainate binding sites). This indole derivative inhibited convulsions induced by NMDA in mice, when administered by both iv and po routes (ED50 = 0.06 and 6 mg/kg, respectively). The effect of the substituents on the terminal phenyl ring of the C-3 side chain was investigated. QSAR analysis suggested that the pKi value decreases with lipophilicity and steric bulk of substituents and increases with the electron donor resonance effect of the groups present in the para position of the terminal phenyl ring. According to these results the terminal phenyl ring of the C-3 side chain should lie in a nonhydrophobic pocket of limited size, refining the proposed pharmacophore model of the glycine binding site associated with the NMDA receptor.

Regionally different N-methyl-D-aspartate receptors distinguished by ligand binding and quantitative autoradiography of [3H]-CGP 39653 in rat brain

1. Binding of D,L-(E)-2-amino-4-[3H]-propyl-5-phosphono-3-pentenoic acid ([3H]-CGP 39653), a high affinity, selective antagonist at the glutamate site of the N-methyl-D-aspartate (NMDA) receptor, was investigated in rat brain by means of receptor binding and quantitative autoradiography techniques. 2. [3H]-CGP 39653 interacted with striatal and cerebellar membranes in a saturable manner and to a single binding site, with KD values of 15.5 nM and 10.0 nM and receptor binding densities (Bmax values) of 3.1 and 0.5 pmol mg-1 protein, respectively. These KD values were not significantly different from that previously reported in the cerebral cortex (10.7 nM). 3. Displacement analyses of [3H]-CGP 39653 in striatum and cerebellum, performed with L-glutamic acid, 3-((+/-)-2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) and glycine showed a pharmacological profile similar to that reported in the cerebral cortex. L-Glutamic acid and CPP produced complete displacement of specific binding with Ki values not significantly different from the cerebral cortex. Glycine inhibited [3H]CGP 39653 binding with shallow, biphasic curves, characterized by a high and a low affinity component. Furthermore, glycine discriminated between these regions (P < 0.005, one-way ANOVA), since the apparent Ki of the high affinity component of the glycine inhibition curve (KiH) was significantly lower (Fisher's protected LSD) in the striatum than the cortex (33 nM and 104 nM, respectively). 4. Regional binding of [3H]-CGP 39653 to horizontal sections of rat brain revealed a heterogeneous distribution of binding sites, similar to that reported for other radiolabelled antagonists at the NMDA site (D-2-[3H]-amino-5-phosphonopentanoic acid ([3H]-D-AP5) and [3H]-CPP). High values of binding were detected in the hippocampal formation, cerebral cortex and thalamus, with low levels in striatum and cerebellum. 5. [3H]-CGP 39653 binding was inhibited by increasing concentrations of L-glutamic acid, CPP and glycine. L-Glutamic acid and CPP completely displaced specific binding in all regions tested, with similar IC50 values throughout. Similarly, glycine was able to inhibit the binding in all areas considered: 10 microM and 1 mM glycine reduced the binding to 80% and 65% of control (average between areas) respectively. The percentage of specific [3H]-CGP 39653 binding inhibited by 1 mM glycine varied among regions (P < 0.05, two-ways ANOVA). Multiple comparison, performed by Fisher's protected LSD method, showed that the inhibition was lower in striatum (72% of control), with respect to cortex (66% of control) and hippocampal formation (58% of control). 6. The inhibitory action of 10 microM glycine was reversed by 100 microM 7-chloro-kynurenic acid (7-CKA), a competitive antagonist of the glycine site of the NMDA receptor channel complex, in all areas tested. Moreover, reversal by 7-CKA was not the same in all regions (P < 0.05, two-ways ANOVA). In fact, in the presence of 10 microM glycine and 100 microM 7-KCA, specific [3H]-CGP 39653 binding in the striatum was 131% of control, which was significantly greater (Fisher's protected LSD) than binding in the hippocampus and the thalamus (104% and 112% of control, respectively). 7. These results demonstrate that [3H]-CGP 39653 binding can be inhibited by glycine in rat brain regions containing NMDA receptors; moreover, they suggest the existence of regionally distinct NMDA receptor subtypes with a different allosteric mechanism of [3H]-CGP 39653 binding modulation through the associated glycine site.

[Colonization by group B hemolytic streptococcus in pregnancy. Note of prevention and therapy of the materno-neonatal infection. Casuistics]

As several international studies show, the knowledge of the wide clinical spectrum of perinatal group B streptococcal infection, particularly of the early and of the late-onset neonatal diseases in GBS carrier mothers, is basically important for medical diagnosis. Risk factors analysis further determines both the diagnosis and the maternal intrapartum chemoprophylaxis. The considerable rate of neonatal disease without risk factors and its possible serious and fatal consequences bring to tendentially non selective prevention approaches that must consider the local background. At Merate Hospital, in a 3 years time, vaginal and rectal specimens for GBS cultures were obtained from 1766 pregnant women either at the 32nd or at the 36th week of gestation and regularly at the labor. 376 women (21.29 percent) resulted GBS carriers; the maternal-fetal contamination rate was 15.42 percent (58/376) i.e. 32.6 per 1000 live births (58/1769). Intrapartum chemoprophylaxis was carried out with i.v. erytromycin, i.v. or i.m. cephalosporins, i.v. ampicillin and per os amoxicillin (which gave the most interesting results). In infants born to mothers who received an antibiotic therapy at labor as compared with those who received no treatment, GBS neonatal colonization was present in 31 of 286 (10.8 percent) versus 27 of 90 (30 percent; P < 0.001); heavy colonization was observed in 10 of 286 (3.4 percent) versus 15 of 90 (16.6 percent; P < 0.001) and early-onset neonatal disease (both symptomatic and asymptomatic) occurred in none of 286 versus 4 of 90 (4.44 percent; P = 0.0031). Perinatal risk factors (no-screened mothers, labor at 36th week of gestation, prolonged membrane rupture) were present only in 1 of 4 GBS infected infants (25 percent). Intrapartum therapy both in carriers and in no-screened women significantly reduced GBS neonatal colonization, particularly the heavy one and, consequently, the early-onset neonatal group B streptococcal disease.

Coexpression with potassium channel subunits used to clone the Y2 receptor for neuropeptide Y

Xenopus oocytes were injected with RNAs for the two inward-rectifier potassium channel subunits Kir3.1 (GIRK1) and Kir3.4 (rcKATP or CIR) in addition to RNA from the neuroblastoma cell line KAN-TS. Potassium currents were evoked by neuropeptide Y in oocytes injected with polyadenylated RNA or with cRNA from pools of a neuroblastoma (KAN-TS) cDNA library, and progressive subdivision of responding pools yielded a single cDNA. The encoded protein contains 381 amino acids, has the seven hydrophobic domains characteristic of G protein-coupled receptors, and is 31% identical to the Y1 receptor: potassium currents were induced by neuropeptide Y (EC50=60pm) and Y2-selective analogues. Coexpression with potassium channel subunits will be a generally useful method for the cloning of G protein-coupled receptors.

Interaction of lacidipine with its receptor binding site supports a slow onset and long duration of action

[3H]lacidipine binding to its receptor was characterized to explain its slow onset and long duration of antihypertensive activity. Binding parameters were studied in guinea pig myocardial and cerebral membrane preparations and compared with another dihydropyridine (DHP) calcium antagonist, isradipine. Lacidipine binds competitively to the DHP calcium antagonist receptor of the L-type calcium channel. The binding is allosterically modulated by verapamil and D-cis diltiazem and activated/inhibited by divalent cations. Association and dissociation kinetics of the binding of lacidipine to the receptor were significantly slower than those of isradipine. In addition, the Bmax of lacidipine binding in guinea pig heart microsomes was significantly higher than those of other dihydropyridine calcium antagonist. The results indicate that the slow onset and long duration of action of lacidipine can be explained principally on the basis of the binding characteristics. Although no biphasic receptor binding kinetics could be detected, a fast equilibrium between the receptor and a second compartment, due to the high lipophilicity of lacidipine, cannot be excluded.

Failure of the putative neuropeptide Y antagonists, benextramine and PYX-2, to inhibit Y2 receptors in rat isolated prostatic vas deferens

1. The pharmacological activity of neuropeptide Y (NPY) and some analogues in inhibiting the twitch contractions induced by electrical stimulation (single pulses at 25 V, 0.15 Hz, 1 ms) in the prostatic portion of the rat isolated vas deferens was investigated. The rank order of agonist potency was: PYY > NPY2-36 > NPY >> NPY13-36 >> NPY18-36 >> [Leu31,Pro34]NPY = hPP, which is consistent with the activation of a Y2 receptor. 2. The putative Y1 and Y2 antagonist, benextramine (BXT), incubated at 100 microM for 10 or 60 min, was ineffective against PYY-induced inhibition of the twitch response, suggesting that the prejunctional Y2 receptor in this tissue is different from the postjunctional one reported in the literature to be sensitive to BXT blockade. 3. The putative NPY antagonist, PYX-2, incubated at 1 microM for 20 min, was completely ineffective in antagonizing PYY-induced inhibition of twitches. 4. The twitch response was totally inhibited by suramin (100 microM) but was little affected by prazosin (1 microM). Furthermore, NPY was without effect on the dose-response curve to ATP in resting conditions. Taken together, these results suggest that in our paradigm, NPY inhibits the release of a purinergic neurotransmitter which mediates contraction of the prostatic portion of the rat vas deferens.

Stereoselective pharmacokinetics of moguisteine metabolites in healthy subjects

We studied the pharmacokinetics of moguisteine, a racemic non-narcotic peripheral antitussive drug, in 12 healthy male subjects after a single oral administration of 200 mg. The unchanged drug was absent in plasma and urine of all subjects. Moguisteine was immediately and completely hydrolyzed to its main active metabolite, the free carboxylic acid M1. Therefore, we evaluated the kinetic profiles of M1, of its enantiomers R(+)-M1 and S(-)-M1, and of M1 sulfoxide optical isomers M2/I and M2/II by conventional and stereospecific HPLC. Maximum plasma concentrations for M1 (2.83 mg/l), M2/I (0.26 mg/l) and M2/II (0.40 mg/l), were respectively reached at 1.3, 1.6 and 1.5 h after moguisteine administration. Plasma concentrations declined after the peak with mean apparent terminal half-lives of 0.65 h (M1), 0.88 h (M2/I) and 0.84 h (M2/II). Most of the administered dose was recovered in urine within 6 h from moguisteine treatment. The systemic and renal clearance values indicated high renal extraction ratio for all moguisteine metabolites, and particularly for M1 sulfoxide optical isomers. Plasma concentration-time profiles and urinary excretion patterns for M1 enantiomers R(+)-M1 and S(-)-M1 were quite similar. Thus, for later moguisteine pharmacokinetic evaluations the investigation of the plasma concentration-time curve and the urinary excretion of the sole racemic M1 through non-stereospecific analytical methods may suffice in most cases.

Carbon fibre micro-electrodes for concomitant in vivo electrophysiological and voltammetric measurements: no reciprocal influences

Differential pulse voltammetry and more recently cyclic voltammetry have been successfully used to monitor basal levels of endogenous chemicals by means of treated carbon fibre microbiosensors inserted in specific brain regions. In this study, feasibility of concomitant in vivo recordings of stable electrophysiological signals and basal ascorbate, catecholaminergic and indolaminergic voltammetric peaks at the same cerebral site by means of a single electrically treated carbon fibre micro electrode (microbiosensor) is presented. The results indicate that these two independent techniques can be combined in vivo at a single electrode, and that voltammetric measurements of unstimulated levels of extracellular compounds do not alter concomitant basal cell firing for a period long enough (more than 6 h) to allow pharmacological manipulations.

Melatonin, a hormone monitorable in vivo by voltammetry?

Melatonin, an indoleamine hormone synthesized in the pinealocytes, is electroactive at the surface of pre-treated carbon fibre microelectrodes (mCFE) in vitro when using differential-pulse voltammetry (DPV), at the specific oxidation potential of approximately +570 mV. In vivo DPV experiments have then been performed in melatonergic regions such as the pineal gland or the suprachiasmatic nucleus (SCH) of anaesthetized adult male rats. These experiments indicated the feasibility of simultaneous measurements of the indolaminergic peak 3, which occurred at approximately +280 mV, due mainly to the oxidation of extracellular 5-hydroxyindoleacetic acid (5HIAA), and a signal at approximately +580 mV which we called peak M. Pharmacological in vivo experiments performed in anaesthetized rats prepared for DPV analysis with the mCFE implanted into the pineal gland or the SCH indicated that intravenous or intra-cerebral injections of exogenous melatonin (5 mg kg-1 or 2 micrograms microliter-1, n = 3, respectively) were followed by a selective and significant increase of in vivo peak M. Other in vivo experiments with anaesthetized rats prepared for DPV analysis with the mCFE into the SCH showed that tryptophan [TRY, 30 mg kg-1 intravenous (i.v.), n = 3] and n-acetyl serotonin (nA-5HT, 5 mg kg-1 i.v., n = 3), both precursors of melatonin, were responsible for a transient but significant increase in the size of peak M (approximately 320% or 126% of control levels within 10 min or 20 min, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Competitive antagonism by phenylglycine derivatives at type I metabotropic glutamate receptors

The metabotropic glutamate receptors (mGluRs) form a family of G-protein-coupled receptors which consists of at least seven members termed mGluR1-mGluR7. These members are classified into subfamilies according to their sequence similarities, signal transduction mechanisms and agonist selectivities. mGluR1 and mGluR5 are coupled to the phosphoinositide hydrolysis/Ca2+ signal transduction and efficiently respond to quisqualate. In this study, we have stably expressed mGluR1 in Chinese hamster ovary cells on which the activation of the phosphoinositide signal transduction pathway was evaluated by means of two methods and their degree of correspondence was analyzed. These two methods involve the Li(+)-dependent accumulation of [3H]inositol-labeled inositol phosphates or the [3H]cytidine-labeled phospholiponucleotide cytidine diphospho (CDP)- diacylglycerol (DAG). The correlation between the two measures was found to be generally uniform for the different agonists evaluated. However, the levels of CDP-DAG were found to be consistently higher. Furthermore, quisqualate showed a differential activity on the two methods behaving as a partial agonist and as a full agonist on the inositol phosphate and the CDP-DAG responses, respectively. On the same cells the activity of a series of carboxyphenylglycines recently described as possible new tools for investigating the role of mGluRs has been evaluated. Three phenylglycine derivatives were tested and found to be competitive antagonists at this mGluR subtype. They inhibited both the phosphoinositide signal transduction pathway and the release of intracellular Ca2+ induced by quisqualate the most potent agonist at mGluR1. The pharmacological nature of these compounds and their relative potencies in antagonizing mGluR1 activation are described.

Assay of moguisteine metabolites in human plasma and urine: conventional and chiral high-performance liquid chromatographic methods

Moguisteine is a novel peripheral non-narcotic antitussive agent. Pharmacokinetic studies in animal and in man showed that no unchanged drug is present in plasma, urine and faeces after oral administration. The main active metabolite, M1, is the free carboxylic acid of moguisteine, which maintains a stereogenic centre and consists of R(+)-M1 and S(-)-M1 enantiomers. M1 is partly metabolized to M2, its sulfoxidation derivative. A conventional HPLC method is described for the simultaneous determination of M1 and M2 in human plasma and urine after administration of therapeutic moguisteine doses. Plasma samples, previously acidified with phosphoric acid, are extracted with dichloromethane; urine samples are analyzed after appropriate dilution with methanol. Chromatography is performed using a Lichrosorb RP2 column and a linear gradient. M1 enantiomers can be determined in plasma extracts and urine samples by a chiral HPLC method using a beta-cyclodextrin column. The analytical characteristics of both HPLC procedures proved to be adequate to analyze samples of subjects treated with therapeutic doses of moguisteine during clinical pharmacokinetic studies.

Comparative receptor autoradiography of ex vivo and in vitro [3H]dizocilpine binding in mouse brain after middle cerebral artery occlusion

In the present study the in vitro and ex vivo distributions of [3H]dizocilpine binding sites in mouse brain after middle cerebral artery occlusion (MCA-O) were compared using receptor autoradiography. The distribution patterns of [3H]dizocilpine binding sites obtained in vitro and ex vivo in normal mouse brain were the same with the highest densities occurring in the hippocampus and cerebral cortex. MCA-O had little or no effect on the in vitro binding density for at least 24 hr post-ischaemia. However after 2-3 days binding densities in the region of infarct were significantly reduced compared to the contralateral cerebral cortex. Further reductions occurred after 5-7 days. By contrast ex vivo [3H]dizocilpine binding was reduced in the infarcted area by 78.7 +/- 4% within 2 hr of the ischaemic insult and at all subsequent times binding was reduced by more than 75%. Ex vivo binding after ischaemia was always less than 30% of in vitro binding and this decrease was apparent within 2 hr of the ischaemic insult whereas in vitro binding was maintained at control levels for at least 24 hr. The neuroprotective activity of the NMDA antagonists dizocilpine and CGP 37849 in this model at different times after MCA-O was assessed. The time scale for receptor access following MCA-O is discussed and it is suggested that although the population of NMDA receptors is maintained in the infarct region for some days access to them in vivo may be sufficiently impaired within 2 or 4 hr of ischaemic insult to reduce the neuroprotective activity of NMDA antagonists after this time.

Allosteric modulation of [3H]CGP 39653 binding by glycine in rat brain

D,L-(E)-2-Amino-4-propyl-5-phosphono-3-pentenoic acid (CGP 39653), a new, high-affinity, selective NMDA receptor antagonist, interacts with rat cortical membranes in a saturable way and apparently to a single binding site, with a KD of 10.7 nM and a receptor density of 2.6 pmol/mg of protein. Displacement analysis of [3H]CGP 39653 binding shows a pharmacological profile similar to that reported for another NMDA antagonist, 3-[(+/-)-2-carboxypiperazin-4-yl]propyl-1-phosphonic acid (CPP). Glycine, however, is able to discriminate between the two ligands; in fact, it does not affect [3H]CPP binding but inhibits [3H]CGP 39653 binding in a biphasic way. D-Serine, another agonist at the strychnine-insensitive glycine binding site of the NMDA receptor complex, inhibits [3H]CGP 39653 binding in the same way as glycine, with a potency that correlates with its binding affinity at the glycine site. In addition, 7-chlorokynurenic acid, an antagonist at the glycine site, is able to reverse the displacement of [3H]CGP 39653 by glycine in a dose-dependent manner. Furthermore, the dissociation rate constant of [3H]CGP 39653 is enhanced in the presence of glycine, whereas the presence of NMDA receptor ligands does not modify the rate of dissociation of [3H]CGP 39653 from the receptor. These results indicate that part of the binding of the NMDA antagonist CGP 39653 can be potently modified by glycine through an allosteric mechanism, and suggest the existence of two antagonist preferring NMDA receptor subtypes that are differentially modulated through the glycine binding site.

In-vivo binding of (+)-[3H]PN 200-110 to peripheral tissues and brain of spontaneously hypertensive rats: effect of lacidipine

The time-course of dihydropyridine receptor occupancy by lacidipine and its relationship with pharmacological activity has been studied in spontaneously hypertensive rat (SHR), as measured by the inhibition of specific (+)-[3H]PN 200-110 binding in-vivo. After oral administration of doses active in reducing blood pressure, lacidipine did not show tissue target differences in respect to binding sites labelled by (+)-[3H]PN 200-110 in cerebral cortex, heart, ileum, bladder and thoracic aorta. The relative occupancy of receptors in heart 60 min after oral administration of 1 mg kg-1 lacidipine was 75%. After 12 h, when lacidipine was still effective in reducing blood pressure in SHR, a low (15%) but detectable proportion of receptors was still occupied by the drug. The percentage decrease of blood pressure was linear with the percentage of receptor occupancy obtained by different doses of lacidipine; that is, there was a close correspondence between ED25 for decrease in blood pressure (0.33 mg kg-1) and ED25 for inhibition of (+)-[3H]PN 200-110 specific binding in the heart (0.36 mg kg-1). The long-lasting effect of lacidipine on blood pressure might be explained by its selective interaction with dihydropyridine binding sites labelled in-vivo by (+)-[3H]PN 200-110.

Inhibition of [3H]-(+)-MK 801 binding to rat brain sections by CPP and 7-chlorokynurenic acid: an autoradiographic analysis

1. The regional binding of [3H]-(+)-5-methyl-10,11-dihydro-5H-dibenzo (a,d)cyclohepten-5,10-imine maleate ([3H]-(+)-MK 801) to sections of rat brain was measured by an in vitro quantitative autoradiographic technique. A heterogeneous distribution of binding sites was observed. 2. High values of binding were detected in the hippocampal formation and cerebral cortex, while very low binding was found in cerebellum. [3H]-(+)-MK 801 binding was not detectable in white matter tracts or in the brain stem. 3. [3H]-(+)-MK 801 binding was inhibited by increasing concentrations of both 7-chlorokynurenate (1-1000 microM) and ((+)-2-carboxypiperazine-4-yl)propyl-1-phosphonic acid (CPP) (0.1-100 microM). High concentrations of both drugs were able to inhibit completely specific [3H]-(+)-MK 801 binding. 4. IC50 values calculated for both 7-chlorokynurenate and CPP-induced [3H]-(+)-MK 801 binding inhibition were similar in all brain regions analyzed. 5. The inhibitory action of 7-chlorokynurenate and that of CPP on [3H]-(+)-MK 801 binding were reversed by addition of glycine and glutamate respectively. 6. It is concluded that activation of glycine and N-methyl-D-aspartate (NMDA) receptors is obligatory for the binding of [3H]-(+)-MK 801 to occur in all of the brain regions examined in the present study. Furthermore, on the basis of the similar regional sensitivities of [3H]-(+)-MK 801 binding to the inhibitory action of 7-chlorokynurenate and CPP, a single pharmacological classification of the NMDA receptor complex in brain is suggested. The cerebellum was not included in the study due to the very low level of [3H]-(+)-MK 801 binding detected under the experimental conditions used.

Ca2+ channel blocking activity of lacidipine and amlodipine in A7r5 vascular smooth muscle cells

Inhibition of the K(+)-stimulated increase in cytosolic free Ca2+ by a series of 1,4-dihydropyridines was evaluated in A7r5 vascular smooth muscle cells loaded with the fluorescent Ca2+ indicator fura-2 acetoxymethyl ester. The IC50 of the drugs, added to suspended cells 3 min before 150 mM KCl, gave the following order of potency: lacidipine (2.76 nM) > nitrendipine (3.81 nM) > amlodipine (4.56 nM) > nifedipine (10.08 nM). A7r5 cells were also exposed to the 1,4-dihydropyridines, at their IC50, for 25 min, and then repeated washout cycles were performed before adding KCl. The Ca2+ channel blocking activity of nifedipine and nitrendipine gradually diminished, disappearing after four washout cycles 25, 55, 115 and 175 min after drug treatment. Amlodipine and lacidipine displayed slow onset and offset of antagonism, their activity becoming stronger with time, in spite of the repeated washes. [3H]Lacidipine was avidly and promptly entrapped in A7r5 cells and was not removed by washout. However, its potency as a Ca2+ channel blocker was not directly related to the amount of drug locked in the cell since it increased with time, indicating that lacidipine binds to the lipid bilayer of the cell membrane and then gradually diffuses towards a specific binding site. This model can, therefore, predict the Ca2+ blocking properties of 1,4-dihydropyridines with slow onset and offset of antagonism and could be employed to evaluate compounds selective for vascular smooth muscle.

Effect of hydrogen peroxide on calcium homeostasis in smooth muscle cells

One of the major biological targets of free radical oxidations, prone, for anatomical reasons, to oxidative challenges, is the cardiovascular system. In the present paper the effect of hydrogen peroxide on intracellular ionized calcium ([Ca2+]i) homeostasis in smooth muscle cells (SMC) is studied, the major aim of the study being a better understanding of the protective effect of antioxidants and Ca2+ channel blockers. The exposure of SMC to 300 microM H2O2 induced a rapid increase of [Ca2+]i, followed by a decrease to a new constant level, higher than the basal before the oxidative challenge. When incubation medium was Ca2+ free, the pattern of [Ca2+]i change was different. The rapid increase was still observed, but it was followed by a rapid decrease to a level only slightly above the basal before the oxidative challenge. The involvement of intracellular Ca2+ stores was tested by using vasopressin, a hormone able to induce discharge of inositol 1,4,5-triphosphate-sensitive Ca2+ stores. When H2O2 was added after vasopressin no [Ca2+]i increase was observed. Treatment of cells, in which the stable increase of [Ca2+]i was induced by H2O2, with disulfide reducing compounds, induced a progressive decrease of [Ca2+]i toward the level observed before the oxidative challenge. Calcium channel blockers and antioxidants, on the other hand, effectively prevented the stabilization of [Ca2+]i at the high steady-state, after the internal Ca2+ release phase. Dihydropyridine Ca2+ channel blockers were by far more active than verapamil and among those the most active was lacidipine. Also the antioxidants trolox and N,N'-diphenyl-1,4-phenylenediamine both prevented the [Ca2+]i unbalance. These results suggest that Ca+ channel blockers and antioxidants, although inactive on oxidative stress-induced Ca2+ release from intracellular stores, prevent the increased influx apparently related to a membrane thiol oxidation.

Lacidipine: a dihydropyridine calcium antagonist with antioxidant activity

Lacidipine, a new, long-acting antihypertensive dihydropyridine calcium antagonist was tested for potential antioxidant effect in a series of tests that consider specific radical species. A direct quenching of several radical species could be measured. Moreover, in biological membranes deriving from rat brain tissue, lacidipine showed an activity comparable to reference antioxidant compounds like vitamin E.

Predisposition to LDL oxidation during copper-catalyzed oxidative modification and its relation to alpha-tocopherol content in humans

The predisposition to LDL oxidation during copper-catalyzed oxidative modification and its relationship with LDL alpha-tocopherol concentration was studied in 41 control subjects. The results show that the predisposition of LDL to oxidation expressed as duration of the inhibition period and rate of the propagation period varied greatly in the controls, but did not correlate with the values of LDL alpha-tocopherol. On the contrary the experiments with alpha-tocopherol incorporated in LDL demonstrate that even small increases of incorporated alpha-tocopherol, under circumstances where other variables were probably largely unaffected, increased proportionally the length of the inhibition period and reduced the rate of the propagation period. The values of LDL alpha-tocopherol achieved after the enrichment turned out to be positively correlated with the duration of the inhibition period and negatively with the rate of the propagation period. Finally the results of this study also show that there was a variability in the LDL alpha-tocopherol decay of different subjects under the same oxidative stress. In our conditions however, the time in which alpha-tocopherol contributed to the LDL protection was much shorter than the mean length of the inhibition period. The results demonstrate that the variability in the predisposition to LDL oxidation during copper-catalyzed oxidative modification is not determined only by the concentration of alpha-tocopherol in LDL and that therefore its value as a sole indicator of antioxidant status is probably inadequate.

Interaction between beta-N-methylamino-L-alanine and excitatory amino acid receptors in brain slices and neuronal cultures

beta-N-Methylamino-L-alanine (BMAA) stimulated the hydrolysis of polyphosphoinositides (PPI) in hippocampal slices prepared from 8-day old rats. The action of BMAA was antagonized by D,L-2-amino-3-phosphonopropionate (an antagonist of metabotropic receptors) and was largely reduced after lowering the concentration of bicarbonate ions from 25 to 1 mM. In cultured cerebellar neurons, stimulation of PPI hydrolysis by BMAA was mediated by the activation of both metabotropic and N-methyl-D-aspartate (NMDA) receptors. However, BMAA exhibited low activity as an NMDA receptor agonist, as reflected by its low efficacy in increasing cGMP formation in cultures incubated in the absence of extracellular Mg2+. A preferential interaction of BMAA with non-NMDA receptors was confirmed by binding studies on crude synaptic membranes from rat brain. Accordingly, BMAA was more potent in displacing specifically bound [3H]glutamate than 3-(2-carboxypiperazin-4-yl)[1,23H]propyl-1-phosphonic acid (CPP) (a selective NMDA receptor ligand). As expected, the affinity of BMAA for [3H]glutamate or [3H]CPP binding sites was greater in the presence of 25 mM bicarbonate. BMAA weakly displaced specifically bound [3H]glycine in the absence of bicarbonate and, in cultured neurons incubated with buffer containing 1 mM bicarbonate, mimicked glycine in reversing the inhibitory action of kynurenic acid on glutamate-stimulated 45Ca2+ influx. Taken collectively, these results suggest that BMAA acts as a mixed agonist of 'metabotropic' and NMDA receptors.

Use of anion-exchange high-performance liquid chromatography for the study of smooth muscle myosin light-chain kinase and its catalytic domain

Avian myosin light-chain kinase from smooth muscle of the gizzard and its catalytic domain, derived from the intact enzyme by trypsin digestion, was purified within 30-40 min by both analytical and preparative anion-exchange high-performance liquid chromatography. The proteins obtained were more than 95% pure and retained their biological activity. The high-performance anion-exchange chromatography protocols represent a significant decrease in purification time when compared with conventional ion-exchange chromatography.

Binding of DL-[3H]-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) to rat cortex membranes reveals two sites or affinity states

A method for measuring [3H]-AMPA binding in rat cortex membranes is described. Specific binding was saturable and accounted for 95% of total binding at 5 nM of [3H]-AMPA. Non linear curve fitting of [3H]-AMPA saturation isotherms suggested the presence of two binding sites: the high affinity site showed a pKd of 8.26 +/- 0.07 (Kd = 5.49 nM) and a Bmax of 0.19 +/- 0.03 pmol/mg protein, whereas the low affinity site indicated a pKd of 7.28 +/- 0.05 (Kd = 52 nM) and a Bmax of 1.30 +/- 0.23 pmol/mg protein. The pharmacological profile of [3H]-AMPA binding has been determined by studying a series of compounds in binding displacement experiments: Quisqualate was the most potent inhibitor of [3H]-AMPA binding (IC50 = 9.7 nM), followed by AMPA (19 nM), CNQX, DNQX and L-Glutamate (272-373 nM). Kainate was a moderate displacer (6.2 microM); Ibotenic acid and glycine were very weak inhibitors (74 and 92 microM, respectively). CPP, GAMS and L-Aspartic acid showed IC50-values of over 400 microM and MK-801, DL-AP5 and NMDA were almost inactive at the maximal concentration used in our experiments.

Smooth muscle myosin light chain kinase: rapid purification by anion exchange high-performance liquid chromatography

A rapid procedure for the purification of myosin light chain kinase present in chicken gizzard smooth muscle using anion exchange high-performance liquid chromatography is described. The procedure allows preparation of microgram amounts of the protein directly from the extract of gizzard myofibrils and then is suitable for the study of myosin light chain kinase in small muscles. The protein was judged to be greater than 95% pure by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The enzyme retains its activity since it catalyzes the calcium-calmodulin-dependent phosphorylation of the 20,000-Da myosin light chain.

Caldesmon: anomalous electrophoretic behaviour in polyacrylamide gel

In SDS gels caldesmon (Mr = 140 kDa) and myosin light chain kinase (Mr = 130 kDa) migrate as a closely separated doublet. When glycerol is added to the gel caldesmon is characterized by an anomalous migration. In fact under this latter condition, the distance between caldesmon and myosin light chain kinase is enhanced by two-three times. The nature of putative caldesmon and myosin light chain kinase was confirmed by physicochemical, enzymatic and immunological methods.

Biochemical characterization of a new highly cardioselective beta-adrenoceptor antagonist

P0160 (1-phenyl-3-(2-(3-(2-cyanophenoxy)-2-hydroxypropyl)amino) ethylhydantoin HCl) is an aryloxypropanolamine which contains a ureido group as part of the hydantoin ring. This molecule was synthesized to obtain a more cardioselective beta-adrenoceptor blocker. Preliminary data have shown that it is as potent as propranolol and four times more cardioselective than atenolol in pharmacological tests in-vitro and in the conscious rat. In the present study we evaluated the interaction of P0160 with beta-adrenoceptors by radioreceptor binding studies and by measuring adenylate cyclase activity coupled to beta-adrenoceptors. The data indicate that P0160 binds with nanomolar affinity to beta-adrenoceptors labelled with [3H]DHA in the rat heart, but with micromolar affinity in the rat lung. Its binding is stereospecific, the S-(-)isomer being 200 times more active than the R-(+) form. P0160's selectivity between cardiac beta 1- and beta 2-receptors was 1388, about 60 times that for metoprolol. Analysis of the thermodynamic characteristics of P0160's interaction with rat heart beta-adrenoceptors indicated antagonist properties of the same order of magnitude as propranolol, as confirmed by adenylate cyclase studies. These data indicate that P0160 is a potent, specific and selective beta 1-adrenoceptor antagonist, and give a molecular explanation for the cardioselective activity found in pharmacological tests.

Natural history of dysgerminoma

Data on 56 patients with pure dysgerminoma are discussed. Forty-nine patients were classified as having new disease or were to have reassessment of disease, and seven cases were to be restaged (one with and six without clinical evidence of disease). Of new and reassessment cases, 44 patients underwent lymphography, 16 underwent peritoneoscopy with diaphragmatic inspection and 30 had peritoneal cytologic testing performed. Positive lymphography resulted in restaging in 31.6% of patients. Diaphragmatic inspection was always negative. Peritoneal cytologic testing was positive for malignant cells in three patients and worsened the stage in one. Pathologic staging of disease was as follows: Stage IA, 24; Stage IB, one Stage IC, one; Stage III peritoneal disease, two. Stage III retroperitoneal disease, 12; Stage III peritoneal and retroperitoneal disease; four. The 5-year relapse-free survival rates were 91% in patients with pathologic Stages IA, IB, and IC; 74% in those with Stage III retroperitoneal disease, and 24% in patients with Stage III peritoneal disease or peritoneal plus retroperitoneal disease. The results indicate that the prognosis is excellent for patients with Stage I and Stage III retroperitoneal disease whereas peritoneal involvement is associated with a poor prognosis.

Management of gestational trophoblastic disease: results of a cooperative study

Three hundred fifty-four evaluable cases of hydatidiform mole diagnosed from 1970 to 1979 in 10 regional hospitals in Lombardy are analyzed in the present report. Twenty-six (7.3%) of the patients developed persistent trophoblastic disease. Younger (less than 20 years) and older (40 years or more) age at diagnosis, a large-for-dates uterus, and ovarian enlargement were associated with an increased risk of developing persistent trophoblastic disease. Twenty-three (9%) cases of persistent trophoblastic disease were observed among 250 women not prophylactically treated, but only in 3 (3%) among 104 who received prophylactic chemotherapy. High-risk groups are defined and the role of prophylactic chemotherapy is discussed.

The lymphatic spread of ovarian germinal and stromal tumors

This paper reports the results of lymphography in germinal and stromal tumors of the ovary. The group of patients is made up of 30 cases of germ cell tumors (70% dysgerminomas) and 29 cases of stromal tumors (62% granulosa cell tumors). The overall incidence of metastases was 29%; 37% in germ cell and 21% in stromal tumors. There was bilateral involvement in 41% of the patients with metastases. The para-aortic region alone was involved in 23%, the iliac alone in 18% and both the regions were simultaneously involved in 59%. In 17/30 operated patients (57%) retroperitoneal node biopsies were performed and diagnostic accuracy was 9/10 in the radiographically positive and 6/7 in the negative cases.