Chronic nicotine improves short-term memory selectively in a G72 mouse model of schizophrenia

BACKGROUND AND PURPOSE

The prevalence of smoking in schizophrenia patients is exceptionally high; it is not known why but many researchers suggest that smoking constitutes a form of self-medication. Among the symptoms of schizophrenia that may be improved by nicotine are cognitive deficits. Hence, we studied the effects of long-term nicotine administration on cognition in a genetic animal model of schizophrenia susceptibility, G72-transgenic (G72Tg) mice.

EXPERIMENTAL APPROACH

The effect of long-term nicotine or saline, administered by osmotic minipumps, on different cognitive domains was assessed in G72Tg mice and controls using a battery of behavioural tests. To investigate the mechanism underlying phenotypic differences, quantitative autoradiographic mapping of nACh receptor subtypes was performed in forebrain structures to explore effects of chronic nicotine exposure on nACh receptor density in wild-type (WT) and G72Tg mice.

KEY RESULTS

Genotype significantly affected the cognitive effects of chronic nicotine administration. Whereas chronic nicotine disrupted cognitive performance in WT mice, it was effective at restoring impaired prepulse inhibition, working memory and social recognition in G72Tg mice. However, long-term spatial learning was further impaired by nicotine in transgenic animals. In contrast, associative learning was protected by G72-expression against the adverse nicotine effects seen in WT animals. G72-expression did not decisively influence nicotine-induced up-regulation of the α4β2*subtype, whereas α7nACh receptor density was differentially altered by genotype or by a genotype·treatment interaction in specific brain areas, most notably hippocampal subregions.

CONCLUSIONS AND IMPLICATIONS

Our data support the hypothesis that nicotine self-medication of schizophrenics improves cognitive symptoms, possibly by facilitating nicotine-induced α7nACh receptor activation in the hippocampus.

The cannabinoid CB₂ receptor-selective phytocannabinoid beta-caryophyllene exerts analgesic effects in mouse models of inflammatory and neuropathic pain

The widespread plant volatile beta-caryophyllene (BCP) was recently identified as a natural selective agonist of the peripherally expressed cannabinoid receptor 2 (CB₂). It is found in relatively high concentrations in many spices and food plants. A number of studies have shown that CB₂ is critically involved in the modulation of inflammatory and neuropathic pain responses. In this study, we have investigated the analgesic effects of BCP in animal models of inflammatory and neuropathic pain. We demonstrate that orally administered BCP reduced inflammatory (late phase) pain responses in the formalin test in a CB₂ receptor-dependent manner, while it had no effect on acute (early phase) responses. In a neuropathic pain model the chronic oral administration of BCP attenuated thermal hyperalgesia and mechanical allodynia, and reduced spinal neuroinflammation. Importantly, we found no signs of tolerance to the anti-hyperalgesic effects of BCP after prolonged treatment. Oral BCP was more effective than the subcutaneously injected synthetic CB₂ agonist JWH-133. Thus, the natural plant product BCP may be highly effective in the treatment of long lasting, debilitating pain states. Our results have important implications for the role of dietary factors in the development and modulation of chronic pain conditions.

European Society of Gastrointestinal Endoscopy, European Society of Gastroenterology and Endoscopy Nurses and Associates, and the European Society of Anaesthesiology Guideline: Non-anesthesiologist administration of propofol for GI endoscopy

Propofol sedation by non-anesthesiologists is an upcoming sedation regimen in several countries throughout Europe. Numerous studies have shown the efficacy and safety of this sedation regimen in gastrointestinal endoscopy. Nevertheless, this issue remains highly controversial. The aim of this evidence- and consensus-based set of guideline is to provide non-anesthesiologists with a comprehensive framework for propofol sedation during digestive endoscopy. This guideline results from a collaborative effort from representatives of the European Society of Gastrointestinal Endoscopy (ESGE), the European Society of Gastroenterology and Endoscopy Nurses and Associates (ESGENA) and the European Society of Anaesthesiology (ESA). These three societies have endorsed the present guideline.

Increased morphine analgesia and reduced side effects in mice lacking the tac1 gene

BACKGROUND AND PURPOSE

Although morphine is a very effective analgesic, its narrow therapeutic index and severe side effects limit its therapeutic use. Previous studies indicated that the pharmacological responses of opioids are modulated by genetic and pharmacological invalidation of tachykinin receptors. Here we address the role of substance P and neurokinin A, which are both encoded by the tachykinin 1 (tac1) gene, as modulators of opioid effects.

EXPERIMENTAL APPROACH

The analgesic and side effect potential of morphine was compared between wild-type and tac1 null mutant mice.

KEY RESULTS

Morphine was a more potent analgesic in tac1 null mutant mice, that is, in the absence of substance P/neurokinin A signalling. Interestingly, the most serious side effect of acute morphine, that is respiratory depression, was reduced in tac1(-/-) animals. Comparing the addictive potential of morphine in wild-type and knockout animals we found that morphine preference was similar between the genotypes. However, the aversive effect of withdrawal precipitated by naloxone in morphine-dependent animals was significantly reduced in tac1 knockout mice. Behavioural sensitization, the underlying mechanism of addiction, was also significantly lower in tac1(-/-) mice.

CONCLUSION AND IMPLICATIONS

The analgesic potential of morphine was increased in tac1 knockout mice. In contrast, both the ventilatory suppressing effect and the addictive potential of morphine were reduced. These results suggest that reducing activity of the tachykinin system may be a possible strategy to improve the pharmacological potential of morphine.

Clinical trial: intravenous pantoprazole vs. ranitidine for the prevention of peptic ulcer rebleeding: a multicentre, multinational, randomized trial

BACKGROUND

Controlled pantoprazole data in peptic ulcer bleeding are few.

AIM

To compare intravenous (IV) pantoprazole with IV ranitidine for bleeding ulcers.

METHODS

After endoscopic haemostasis, 1256 patients were randomized to pantoprazole 80 mg+8 mg/h or ranitidine 50 mg+13 mg/h, both for 72 h. Patients underwent second-look endoscopy on day 3 or earlier, if clinically indicated. The primary endpoint was an overall outcome ordinal score: no rebleeding, rebleeding without/with subsequent haemostasis, surgery and mortality. The latter three events were also assessed separately and together.

RESULTS

There were no between-group differences in overall outcome scores (pantoprazole vs. ranitidine: S0: 91.2 vs. 89.3%, S1: 1.5 vs. 2.5%, S2: 5.4 vs. 5.7%, S3: 1.7 vs. 2.1%, S4: 0.19 vs. 0.38%, P = 0.083), 72-h clinically detected rebleeding (2.9% [95% CI 1.7, 4.6] vs. 3.2% [95% CI 2.0, 4.9]), surgery (1.9% [95% CI 1.0, 3.4] vs. 2.1% [95% CI 1.1, 3.5]) or day-3 mortality (0.2% [95% CI 0, 0.09] vs. 0.3% [95% CI 0, 1.1]). Pantoprazole significantly decreased cumulative frequencies of events comprising the ordinal score in spurting lesions (13.9% [95% CI 6.6, 24.7] vs. 33.9% [95% CI 22.1, 47.4]; P = 0.01) and gastric ulcers (6.7% [95% CI 4, 10.4] vs. 14.3% [95% CI 10.3, 19.2], P = 0.006).

CONCLUSIONS

Outcomes amongst pantoprazole and ranitidine-treated patients were similar; pantoprazole provided benefits in patients with arterial spurting and gastric ulcers.

Preprodynorphin mediates locomotion and D2 dopamine and mu-opioid receptor changes induced by chronic 'binge' cocaine administration

Evidence suggests that the kappa-opioid receptor (KOP-r) system plays an important role in cocaine addiction. Indeed, cocaine induces endogenous KOP activity, which is a mechanism that opposes alterations in behaviour and brain function resulting from repeated cocaine use. In this study, we have examined the influence of deletion of preprodynorphin (ppDYN) on cocaine-induced behavioural effects and on hypothalamic-pituitary-adrenal axis activity. Furthermore, we have measured mu-opioid receptor (MOP-r) agonist-stimulated [(35)S]GTPgammaS, dopamine D(1), D(2) receptor and dopamine transporter (DAT) binding. Male wild-type (WT) and ppDYN knockout (KO) mice were injected with saline or cocaine (45 mg/kg/day) in a 'binge' administration paradigm for 14 days. Chronic cocaine produced an enhancement of locomotor sensitisation in KO. No genotype effect was found on stereotypy behaviour. Cocaine-enhanced MOP-r activation in WT but not in KO. There was an overall decrease in D(2) receptor binding in cocaine-treated KO but not in WT mice. No changes were observed in D(1) and DAT binding. Cocaine increased plasma corticosterone levels in WT but not in KO. The data confirms that the endogenous KOP system inhibits dopamine neurotransmission and that ppDYN may mediate the enhancement of MOP-r activity and the activation of the hypothalamic-pituitary-adrenal axis after chronic cocaine treatment.

Early age-related cognitive impairment in mice lacking cannabinoid CB1 receptors

The molecular mechanisms contributing to the normal age-related decline of cognitive functions or to pathological learning and memory impairment are largely unknown. We demonstrate here that young mice (6-7 weeks) with a genetic deletion of the cannabinoid CB1 receptor performed as well as WT mice, or often better, in a number of learning and memory paradigms, including animal models of skill-learning, partner recognition, and operant conditioning. In contrast, the performance of mature mice (3-5 months) lacking CB1 receptors was much worse than that of age-matched WT animals. In most tests, these mice performed at the same level as old animals (14-17 months), suggesting that the decline in cognitive functions is accelerated in the absence of CB1 receptors. This rapid decline in CB1-deficient animals is accompanied by a loss of neurons in the CA1 and CA3 regions of the hippocampus.

Formulation of controlled release drug preparations with antacid effect

Opportunities for the formulation of long-acting antacid preparations were demonstrated summarizing the results of pharmaceutical technological experiments. The telemetric intragastric data were in correlation with the in vitro measurements and demonstrated the significantly higher bioavailability of long-acting antacid preparations.

New Ecdysteroids from Serratula tinctoria

Six new ecdysteroids have been isolated from SERRATULA TINCTORIA; these are: the 2,22- and 3,22-diacetates of 20-hydroxyecdysone, 5beta-hydroxyrubrosterone, 3-epi-poststerone, 3-epi-rubrosterone, and 22-oxo-20-hydroxyecdysone. These minor compounds were found together with the known ecdysteroids, 20-hydroxyecdysone, its 2-, 3-, and 22-monoacetates, rubrosterone, poststerone, polypodine B (5beta,20-dihydroxyecdysone), pterosterone (25-deoxy-20,24-dihydroxyecdysone), and makisterone C (24-ethyl-20-hydroxyecdysone). All these ecdysteroids were isolated by a combination of several chromatographic techniques (liquid chromatography on alumina, DCCC, and HPLC), then identified using standard mass spectrometric and 2D (1)H-NMR techniques.

Experimental syphilis and serological examination for treponematosis in hares

Of 202 captive hares studied, many of which had lesions on their external genital organs or testicular atrophy or both, 27% had positive serological tests for syphilis although dark-field examination of extracts of atrophic testes was negative. A total of 12 hares that were nonreactive for the serological test for syphilis was inoculated with Treponema pallidum, 9 intratesticularly and 3 intradermally. Six of the animals inoculated intratesticularly exhibited orchitis after 7 days with an associated accumulation of treponemes. No chancres developed in the intracutaneously inoculated animals during a 27-day period of observation. These results provide additional evidence to support the contention that endemic treponematosis occurs in wild hares and suggest that hares are moderately resistant to experimental infection with T. pallidum.