An overall view of the most common experimental models for multiple sclerosis.

Multiple sclerosis (MS) is a complex chronic disease with an unknown etiology. It is considered an inflammatory demyelinating and neurodegenerative disorder of the central nervous system (CNS) characterized, in most cases, by an unpredictable onset of relapse and remission phases. The disease generally starts in subjects under 40; it has a higher incidence in women and is described as a multifactorial disorder due to the interaction between genetic and environmental risk factors. Unfortunately, there is currently no definitive cure for MS. Still, therapies can modify the disease's natural history, reducing the relapse rate and slowing the progression of the disease or managing symptoms. The limited access to human CNS tissue slows down. It limits the progression of research on MS. This limit has been partially overcome over the years by developing various experimental models to study this disease. Animal models of autoimmune demyelination, such as experimental autoimmune encephalomyelitis (EAE) and viral and toxin or transgenic MS models, represent the most significant part of MS research approaches. These models have now been complemented by ex vivo studies, using organotypic brain slice cultures and in vitro, through induced Pluripotent Stem cells (iPSCs). We will discuss which clinical features of the disorders might be reproduced and investigated in vivo, ex vivo, and in vitro in models commonly used in MS research to understand the processes behind the neuropathological events occurring in the CNS of MS patients. The primary purpose of this review is to give the reader a global view of the main paradigms used in MS research, spacing from the classical animal models to transgenic mice and 2D and 3D cultures.

Neurobiological mechanisms of cannabinoid addiction.

The endocannabinoid system is implicated in the regulation of a variety of physiological processes, among which conditioning, motivation, habit forming, memory, learning, and cognition play pivotal roles in drug reinforcement and reward. In this article we will give a synopsis of last developments in research on cannabinoid actions on brain reward circuits coming from behavioral, neurochemical and electrophysiological studies. Central cannabinoid-induced effects as measured by animal models of addiction, in vivo cerebral microdialysis, in vitro and in vivo electrophysiological recording techniques, will be reviewed. Brain sites that have been implicated in the mediation of addictive cannabinoid properties include primarily the ventral tegmental area, the nucleus accumbens, and the medial prefrontal cortex, although the amygdala, the substantia nigra, the globus pallidus, and the hippocampus have also been shown to be critical structures mediating motivational and reinforcing effects of cannabinoids. Putative neurobiological mechanisms underlying these effects will be delineated.

Cannabinoid self-administration in rats: sex differences and the influence of ovarian function.

BACKGROUND AND PURPOSE: We recently demonstrated the existence of strain differences in self-administration of the cannabinoid CB1 receptor agonist WIN55,212-2 (WIN) by Long Evans (LE) and Lister Hooded (LH) but not Sprague-Dawley (SD) male rats. This follow-up study is aimed at verifying whether sex and ovarian hormones might also be critical factors in the initiation, retention and extinction of WIN self-administration. EXPERIMENTAL APPROACH: LE, LH and SD male and female rats, the latter either intact or bilaterally ovariectomized (OVX), were trained to self-administer WIN (12.5 microg kg(-1) per infusion) under a FR1 reinforcement schedule, using lever-pressing. KEY RESULTS: Data showed that contrary to the findings in SD rats, LE and LH rats developed robust cannabinoid intake, with rates of responding for WIN being constantly higher in intact females than in males (+45 and +42% for LE and LH strains, respectively). In comparison with intact females, OVX females of both strains acquired self-administration at lower rates, displaying slower acquisition, lower drug intake (-42 and -52% for LE and LH, respectively) and longer extinction. CONCLUSIONS AND IMPLICATIONS: These findings provide the first evidence of significant sex differences in cannabinoid self-administration, females acquiring stable WIN intake at higher rates and more rapidly than males. Moreover, when compared to intact females, a lower percentage of LE and LH OVX rats acquired and maintained stable drug intake, suggesting that ovarian hormones might represent a critical factor in modulating the reinforcing effect of cannabinoids.

Methoxetamine affects brain processing involved in emotional response in rats.

BACKGROUND AND PURPOSE: Methoxetamine (MXE) is a novel psychoactive substance that is emerging on the Internet and induces dissociative effects and acute toxicity. Its pharmacological effects have not yet been adequately investigated. EXPERIMENTAL APPROACH: We examined a range of behavioural effects induced by acute administration of MXE (0.5-5 mg·kg-1 ; i.p.) in rats and whether it causes rapid neuroadaptive molecular changes. KEY RESULTS: MXE (0.5-5 mg·kg-1 ) affected motor activity in a dose- and time-dependent manner, inducing hypermotility and hypomotility at low and high doses respectively. At low and intermediate doses (0.5 and 1 mg·kg-1 ), MXE induced anxious and/or obsessive-compulsive traits (marble burying test), did not significantly increase sociability (social interaction test) or induce spatial anxiety (elevated plus maze test). At a high dose (5 mg·kg-1 ), MXE induced transient analgesia (tail-flick and hot-plate test), decreased social interaction time (social interaction test) and reduced immobility time while increasing swimming activity (forced swim test), suggesting an antidepressant effect. Acute MXE administration did not affect self-grooming behaviour at any dose tested. Immunohistochemical analysis showed that behaviourally active doses of MXE (1 and 5 mg·kg-1 ) increased phosphorylation of ribosomal protein S6 in the medial prefrontal cortex and hippocampus. CONCLUSIONS AND IMPLICATIONS: MXE differentially affected motor activity, behaviour and emotional states in rats, depending on the dose tested. As reported for ketamine, phosphorylation of the ribosomal protein S6 was increased in MXE-treated animals, thus providing a 'molecular snapshot' of rapid neuroadaptive molecular changes induced by behaviourally active doses of MXE.

Synthesis, molecular modeling, and opioid receptor affinity of 9, 10-diazatricyclo[4.2.1.1(2,5)]decanes and 2,7-diazatricyclo[4.4.0. 0(3,8)]decanes structurally related to 3,8-diazabicyclo[3.2. 1]octanes.

Various lines of evidence, including molecular modeling studies, imply that the endoethylenic bridge of 3,8-diazabicyclo[3.2. 1]octanes (DBO, 1) plays an essential role in modulating affinity toward mu opioid receptors. This hypothesis, together with the remarkable analgesic properties observed for N(3) propionyl, N(8) arylpropenyl derivatives (2) and of the reverted isomers (3), has prompted us to insert an additional endoethylenic bridge on the piperazine moiety in order to identify derivatives with increased potency toward this receptor class. In the present report, we describe the synthesis of the novel compounds 9,10-diazatricyclo[4.2. 1.1(2,5)]decane (4) and 2,7-diazatricyclo[4.4.0.0(3,8)]decane (5), as well as the representative derivatives functionalized at the two nitrogen atoms by propionyl and arylpropenyl groups (6a-e, 7a-d). Opioid receptor binding assays revealed that, among the compounds tested, the N-propionyl-N-cinnamyl derivatives 6a and 7a exhibited the highest mu-receptor affinity, and remarkably, compound 7a displayed in vivo (mice) an analgesic potency 6-fold that of morphine.

Chronic morphine and naltrexone fail to modify mu-opioid receptor mRNA levels in the rat brain.

Previous radioligand-binding studies have reported conflicting results concerning the effect of chronic morphine administration on the regulation of mu-opioid receptor (MOR) density. On the other hand, chronic administration of an opioid antagonist, such as naltrexone, has been shown to increase the density of the MOR. In order to determine if the changes in the MOR are associated with alterations in receptor mRNA levels, we investigated MOR gene expression following chronic treatment with morphine and/or naltrexone. MOR mRNA levels, determined by the ribonuclease protection assay (RPA), were unchanged with respect to control during chronic morphine treatment and morphine withdrawal in each of the analysed brain areas. Furthermore, chronic administration of naltrexone did not result in changes of MOR mRNA levels in rat striatum of naive and morphine-dependent rats, suggesting that the up-regulation of the MOR density, at least in this tissue, is not regulated at transcriptional level.

Dopamine D1 and opioid receptor binding changes in the limbic system of sleep deprived rats.

Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 h) the rat displayed particular behavior characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. Our previous results indicated that this behavior was potently antagonized by the administration of the D1 selective antagonist SCH 23390 and by the opioid antagonist naloxone. In this paper we show that concomitantly to this behavior, an increased number of D1 receptors associated with an increased dopamine-stimulated adenylate cyclase activity is present in the limbic system but not in the striatum of these animals. On the contrary, a decreased Bmax of mu and delta opioid receptors was found in the same brain area. These data suggest an active role of limbic dopamine and opioid systems in the generation of arousal and insomnia related to sleep deprivation-induced stress.

Thyroid involvement in patients with overt HCV-related mixed cryoglobulinaemia.

BACKGROUND: Mixed cryoglobulinaemia (MC), a systemic vasculitis associated with hepatitis C virus (HCV) infection in >90% of cases, is frequently complicated by multiple organ involvement. The prevalence of thyroid disorders in MC has not yet been studied. AIM: To investigate the prevalence and clinical features of thyroid involvement in patients with HCV-associated MC (HCV + MC). DESIGN: Case-control study. METHODS: HCV + MC patients (n = 93, 17 men and 76 women, mean +/- SD age 63 +/- 10 years, mean disease duration 14 +/- 7 years) consecutively referred to the Rheumatology Unit were matched by sex and age (+/- 2 years) to (i) 93 patients with chronic C hepatitis (CH) without MC and (ii) 93 healthy (HCV-negative) controls from the local population. Measurements included prevalence of hypo- or hyperthyroidism, thyroid autoantibodies, thyroid nodules and thyroid cancer. RESULTS: By McNemar's chi(2) test, the following thyroid abnormalities were significantly more frequent in HCV + MC patients than in HCV-negative controls: serum anti-thyroperoxidase autoantibody (AbTPO) (28% vs. 9%, p = 0.001); serum AbTPO and/or anti-thyroglobulin autoantibody (31% vs. 12%, p = 0.004); subclinical hypothyroidism (11% vs. 2%, p = 0.038); thyroid autoimmunity (35% vs. 16%, p = 0.006). Serum AbTPO were also significantly more frequent in HCV + MC patients than in CH controls (28% vs. 14%, p = 0.035). DISCUSSION: The prevalence of thyroid disorders is increased in patients with HCV-related mixed cryoglobulinaemia. We suggest careful monitoring of thyroid function in these patients.

Sleep deprivation decreases mu and delta opioid receptor binding in the rat limbic system.

Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 h) the rat displayed particular behavior characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. Our previous results indicated that this behavior was antagonized by the administration of the opioid receptor antagonist naloxone and increased by opioid agonists. In this paper we show that concomitantly with this behavior, a decreased Bmax of mu and delta opioid receptors is present in the limbic system of these animals. These data suggest an active role of limbic mu and delta receptors in the generation of arousal and insomnia related to sleep deprivation induced stress.

Chronic imipramine, L-sulpiride and mianserin decrease corticotropin releasing factor levels in the rat brain.

Among clinically effective antidepressant drugs, the action mechanism of mianserin has recently been related to variations in corticotropin releasing factor (CRF) levels in the rat locus coeruleus. We describe a specific effect on CRF levels after chronic treatment with different antidepressants: mianserin (10 mg/kg), imipramine (20 mg/kg), both for 21 days, or L-sulpiride (1 mg/kg) for 15 days. While all antidepressants used greatly decreased CRF concentrations in the hypothalamus, only mianserin decreased CRF concentrations by 40% in extrahypothalamic sites. Acute treatments failed to modify CRF levels. Chronic treatment with mianserin did not affect CRF density either in the hypothalamus or the extrahypothalamic areas. This new finding may add another facet to the therapeutic action of certain antidepressants and in particular to the atypical profile of mianserin.

Sleep deprivation increases dopamine D1 receptor antagonist [3H]SCH 23390 binding and dopamine-stimulated adenylate cyclase in the rat limbic system.

Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 h) the rats displayed particular behaviour characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. Our previous results indicated that this behaviour was potently antagonized by the administration of the D1-selective antagonist SCH 23390. In this paper we show that concomitantly to this behaviour, an increased number of D1 receptors associated with an increased dopamine-stimulated adenylate cyclase activity is present in the limbic system but not in the striatum of these animals. These data suggest an active role of limbic D1 receptors in the generation of arousal and insomnia related to sleep deprivation induced stress.

Dopamine and opioids interactions in sleep deprivation.

1. Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 hrs) the rat displayed particular behavior characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. 2. Our results indicate that this behavior is potently antagonized by the administration of D1 antagonist SCH 23390 and by the opioid antagonist naloxone. 3. We also show that concomitantly to this behavior, an increased number of D1 receptors associated with an increased dopamine-stimulated adenylate cyclase activity is present in the limbic system but not in the striatum of these animals. On the contrary, a decreased Bmax of mu and delta opioid receptors was found in the same brain areas. 4. These data suggest an active role of limbic dopamine and opioid system in the generation of arousal and insomnia related to sleep deprivation-induced stress.

Sleep deprivation in the rat: an animal model of mania.

The model of sleep deprivation in rats by the platform method has been extensively studied in our laboratory as a possible animal model of mania. At the end of the period of sleep deprivation, the rat does not fall asleep as soon as it is returned to its home cage, but shows a period of wakefulness of about 30 min, during which the animal presents a cohort of symptoms that appear to mimic those present in idiopathic mania. In particular, during this period the animal displays insomnia, a high degree of hyperactivity, irritability, aggressiveness, hypersexuality and stereotypy. Haloperidol (0.2 mg/kg) was effective in reducing latency to sleep, while L-sulpiride was much weaker (< 50 mg/kg). The dopamine D1 receptor antagonist SCH 23390 exhibited an extremely high potency and efficacy in reducing sleep latency, a significant effect being observed with 3 micrograms/kg. The administration of the specific D1 receptor agonist SKF 38393 markedly prolonged the period of insomnia with the correlated behavioral syndrome. When lithium was added to the diet and consumed during the sleep deprivation period in adequate amounts to produce serum lithium levels of 0.7-1.0 mEq/l, sleep latency and locomotor activity were significantly reduced. The administration of naloxone (1-10 mg/kg) reduced the latency to sleep in a dose-related manner. By contrast, morphine (1 and 5 mg/kg, i.p.), beta-endorphin and [D-Ala2,D-Leu5]enkephalin (i.c.v., 2 and 1 micrograms, respectively) markedly prolonged the insomnia. The model not only represents a confirmation in the rat that sleep loss often precedes and may trigger a manic episode in man, but suggests that an opioid-dopamine interaction may play a pathogenetic role in mania.

Antinociceptive action of DBO 17 and DBO 11 in mice: two 3,8 diazabicyclo (3.2.1.) octane derivates with selective mu opioid receptor affinity.

Two 3,8 diazabicyclo (3.2.1.) octane derivates, namely DBO 17 and DBO 11, were studied for the opioid-like activity. In the rat brain membrane preparation binding studies, DBO 17 and DBO 11 showed a high affinity and selectivity for the mu opioid receptor (Ki's: 5.1 and 25 nM, respectively). DBO 17 and DBO 11 inhibited the nociceptive response in the hot-plate test of mice with ED50 values of 0.16 mg/kg and 0.44 mg/kg, respectively. The antinociceptive action of both DBO 17 and DBO 11 was blocked by naloxone. Tolerance to the antinociceptive action of DBO 17 and DBO 11 was present after 13 and 7 days of repeated treatment, respectively. Both DBO 17 and DBO 11 were ineffective in morphine-tolerant mice and vice versa. Chronic treatments (three times daily for seven consecutive days) of DBO 17 and DBO 11 induced a naloxone-precipitated withdrawal syndrome in DBO 17 treated mice similar to that in morphine treated mice, whereas in DBO 11 treated mice abstinence signs were virtually absent. These results indicate an interesting pharmacological profile that suggests these compounds as possible new candidates for the clinical treatment of pain.

Kartagener's syndrome and rheumatoid arthritis: an unusual association.

We report the case of a 66-year-old caucasian woman affected by Kartagener's syndrome (KS), a genetically transmitted disorder characterised by situs viscerum inversus, bronchiectasis and sinusitis, who also developed rheumatoid arthritis (RA). The impaired mucociliary function typical of KS caused recurrent paranasal sinus and lung infections, as shown by CT scans of the sinuses and chest. The coexistence of KS and RA in our patient was probably accidental. Given the small number of patients in whom an association of the two disorders has been described, it is impossible to establish whether KS might play a role in the pathogenesis of RA.

Synthesis and opioid receptor affinity of bivalent ligands derived from 3,8-diazabicyclo(3.2.1)octanes.

A new series of bivalent ligands (2a-d), derived from the previously reported analgesic 3-cinnamyl-8-propionyl-3,8-diazabicyclo(3.2.1)octane (1a), has been synthesized and tested in vitro for their affinity towards opioid receptors and in vivo for their analgesic potency. None of the new compounds showed either appreciable affinity for opioid receptors or analgesic activity comparable to that of the model 1a.

Synthesis and mu-opioid receptor affinity of a new series of nitro substituted 3,8-diazabicyclo[3.2.1]octane derivatives.

A new series of analogues (1c-j; 2c-i) of the previously reported analgesic 3,8-diazabicyclo[3.2.1]octanes (1a,b; 2a,b) was synthesized and tested for their affinity towards mu-opioid receptors. Modifications were introduced either at the cinnamyl or the acyl side chains. The majority of the new compounds, with the exception of 1c,j and 2c, showed Ki values better or comparable with those of the models.

Benzocondensed derivatives as rigid analogues of the mu-opioid agonist 3(8)-cinnamyl-8(3)-propionyl-3,8-diazabicyclo[3.2.1]octanes: synthesis, modeling, and affinity.

A new series of rigid analogues (1a-g, 2a-g) of the previously reported analgesic 3-cinnamyl-8-propionyl-3,8-diazabicyclo[3.2.1]octane (I) and its reverted isomer 3-propionyl-8-cinnamyl (II) were synthesized, in which the cinnamyl substituent is incorporated in benzocondensed bicyclic systems. Binding assays for the affinity towards mu receptors indicated that, while in the reverted series 2 the beta-naphthylmethyl (2d) and the benzocycloheptenylmethyl derivative (2g) favorably compared with II, all compounds 1 displayed a mu-affinity lower than that of the parent I. Modeling studies suggest that the flexibility of the cinnamyl side chain plays an important role for activity.

[Hepatitis C virus infection and arthritis. A clinico-serological investigation of arthritis in patients with or without cryoglobulinemic syndrome]. / Epatite C e artrite. Studio clinico-sierologico dell'artrite in pazienti con e senza sindrome crioglobulinemica.

OBJECTIVE: To compare the clinico-serological features of arthritis from two HCV+ patient groups characterized by mixed cryoglobulinemia (MC) or chronic hepatitis (CH). METHODS: We retrospectively studied 157 MC patients (119 females, mean age 64.8 yrs, range 36-88) and 155 CH patients (103 females, mean age 58.8 yrs, range 30-81). Patients with HBV and/or HIV co-infections and a follow-up shorter than 1 year were excluded. MC was classified according to standard criteria, while CH classification was based on Desmet's criteria. RESULTS: No differences in epidemiology were demonstrated between the two series of patients. Although significantly prevalent in MC patients, extra-hepatic manifestations including nephropathy, neuropathy, pneumopathy, mixed cryoglobulins, RF positivity and hypocomplementemia were detected in both patient groups. Arthritis was present in 23 CH (15%) and 12 MC (8%) patients. A symmetrical polyarthritis was observed in 87% of 23 CH patients, while cryoglobulinemic arthritis was invariably asymmetrical and pauciarticular. Unlike MC patients, who had a constantly non-erosive arthritis, in 7/23 CH patients arthritis was erosive. Steroids and/or hydroxycloroquine or D-penicillamine were safe and useful in controlling the arthritis over the short-medium time, although clinical response was more evident in MC patients. Instead, in 5/23 CH and 3/12 MC patients, interferon-alpha treatment was able to trigger or exacerbate the arthritis despite a good control of liver function. CONCLUSIONS: HCV infection seems to be, possibly in genetically predisposed patients, responsible for arthritis at times similar to rheumatoid arthritis. In these patients a careful assessment of the interferon-alpha treatment is mandatory owing to the potential "arthritogenic effect" due to its immunoregulatory properties.

Solid lipid nanoparticle preparation by a warm microemulsion based process: influence of microemulsion microstructure.

Warm microemulsions (WME) containing lipids are used as starting systems to obtain solid lipid nanoparticles (SLN) in alternative processes to those based on high pressure homogenization technique. SLN characteristics can be influenced by the microemulsion composition and the specific conditions adopted in the quenching process related to the transformation of WME into nanoparticles. To establish optimized conditions for the production of SLN starting from WME, in a first step of this work we have defined the microstructure of warm microemulsions highlighted in the lecithin (LCT)/water (W)/tripalmitin (TP)/1-butanol (B)/taurocholate sodium salt (ST) phase behavior at 70°C. Moreover, we have further studied the LCT/W/TP/B system by evaluating the effect on the microemulsion area due to the LCT/B weight ratio, the replacement of 1-butanol with different alcohols (ROH), and the addition of taurocholate sodium salt (ST) at different LCT/ST weight ratios. The microstructure of the isotropic phase region obtained in the presence of ST has been characterized by both (1)H NMR PGSE measurements and electrical conductivity. The characteristics of final nanoparticles are discussed taking into account both the microstructure of the parent WME and the conditions of the quenching process leading to SLN. The present results highlight the relevance of the microstructural characteristic of WME to assure the obtainment of SLN with average diameter in the order of 100-2000 nm and narrow size distribution.