Ethanol and the benzodiazepine-GABA receptor-ionophore complex

Ethanol has a pharmacological profile similar to that of classes of drugs like benzodiazepines and barbiturates, which enhance GABAergic transmission in the mammalian CNS. Several lines of behavioral, electrophysiological and biochemical studies suggest that ethanol may bring about most of its effects by enhancing GABAergic transmission. Recently, ethanol at relevant pharmacological concentrations has been shown to enhance GABA-induced 36Cl-fluxes in cultured spinal cord neurons, synaptoneurosomes and microsacs. These enhancing effects of ethanol were blocked by GABA antagonists. Ro15-4513, an azido analogue of classical BZ antagonist Ro15-1788, reversed most of the behavioral effects of ethanol and other effects involving 36Cl-flux studies. The studies summarized below indicate that most of the pharmacological effects of ethanol can be related to its effects on GABAergic transmission.     

Über eine Tetrahydroisochinolinverbindung mit analgetischer Wirkung

Summary Ro 4-1778/1 (1-(p-Chlorphenethyl)-6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline) showed in pharmacological tests distinct analgetic effects similar to those of codeine as well as some spasmolytic activity resembling that of papaverine, whereas its side effects were absent or at least considerably less pronounced than those known for codeine.     

Emerging roles of calpain proteolytic systems in macrophage cholesterol handling

Calpains are Ca²⁺-dependent intracellular proteases that play central roles in the post-translational processing of functional proteins. In mammals, calpain proteolytic systems comprise the endogenous inhibitor calpastatin as well as 15 homologues of the catalytic subunits and two homologues of the regulatory subunits. Recent pharmacological and gene targeting studies in experimental animal models have revealed the contribution of conventional calpains, which consist of the calpain-1 and -2 isozymes, to atherosclerotic diseases. During atherogenesis, conventional calpains facilitate the CD36-dependent uptake of oxidized low-density lipoprotein (LDL), and block cholesterol efflux through ATP-binding cassette transporters in lesional macrophages, allowing the expansion of lipid-enriched atherosclerotic plaques. In addition, calpain-6, an unconventional non-proteolytic calpain, in macrophages reportedly potentiates pinocytotic uptake of native LDL, and attenuates the efferocytic clearance of apoptotic and necrotic cell corpses from the lesions. Herein, we discuss the recent progress that has been made in our understanding of how calpain contributes to atherosclerosis, in particular focusing on macrophage cholesterol handling.     

An antineoplastic C14-labeled methylhydrazine derivative in P815 mouse leukemia. a metabolic study

Zusammenfassung Die endst?ndige N-Methyl-Gruppe von 1-Methyl-C¹⁴-2-p-(isopropylcarbamoyl)benzylhydrazin-Hydrochlorid (MBH) (Ro 4-6467) erwies sich in In-vivo-Experimenten metabolisch labil, wird teilweise oxydiert und Bestandteil des Formiatpools.      

On the mechanism of inhibition of p27 degradation by 15-deoxy-Δ12,14-prostaglandin J 2 in lymphoblasts of Alzheimer’s disease patients

It has been proposed that neuroinflammation, among other factors, may trigger an aberrant neuronal cell cycle re-entry leading to neuronal death. Cell cycle disturbances are also detectable in peripheral cells from Alzheimer’s disease (AD) patients. We previously reported that the anti-inflammatory 15- deoxy-Δ^12,14-prostaglandin J ₂ (15d-PGJ ₂) increased the cellular content of the cyclin-dependent kinase inhibitor p27, in lymphoblasts from AD patients. This work aimed at elucidating the mechanisms of 15d-PGJ ₂-induced p27 accumulation. Phosphorylation, half-life, and the nucleo-cytoplasmic traffic of p27 protein were altered by 15d-PGJ2 by mechanisms dependent on PI3K/Akt activity. 15d-PGJ ₂ prevents the calmodulin-dependent Akt overactivation in AD lymphoblasts by blocking its binding to the 85-kDa regulatory subunit of PI3K. These effects of 15d-PGJ ₂ were not mimicked by 9,10-dihydro-15-deoxy-Δ^12,14- prostaglandin J ₂, suggesting that 15d-PGJ ₂ acts independently of peroxisome proliferator-activated receptor γ activation and that the α,β-unsaturated carbonyl group in the cyclopentenone ring of 15d-PGJ ₂ is a requisite for the observed effects. Received 14 July 2008; received after revision 2 September 2008; accepted 12 September 2008     

Neuronal calcium signaling: function and dysfunction

Calcium (Ca²⁺) is an universal second messenger that regulates the most important activities of all eukaryotic cells. It is of critical importance to neurons as it participates in the transmission of the depolarizing signal and contributes to synaptic activity. Neurons have thus developed extensive and intricate Ca²⁺ signaling pathways to couple the Ca²⁺ signal to their biochemical machinery. Ca²⁺ influx into neurons occurs through plasma membrane receptors and voltage-dependent ion channels. The release of Ca²⁺ from the intracellular stores, such as the endoplasmic reticulum, by intracellular channels also contributes to the elevation of cytosolic Ca²⁺. Inside the cell, Ca²⁺ is controlled by the buffering action of cytosolic Ca²⁺-binding proteins and by its uptake and release by mitochondria. The uptake of Ca²⁺ in the mitochondrial matrix stimulates the citric acid cycle, thus enhancing ATP production and the removal of Ca²⁺ from the cytosol by the ATP-driven pumps in the endoplasmic reticulum and the plasma membrane. A Na⁺/Ca²⁺ exchanger in the plasma membrane also participates in the control of neuronal Ca²⁺. The impaired ability of neurons to maintain an adequate energy level may impact Ca²⁺ signaling: this occurs during aging and in neurodegenerative disease processes. The focus of this review is on neuronal Ca²⁺ signaling and its involvement in synaptic signaling processes, neuronal energy metabolism, and neurotransmission. The contribution of altered Ca²⁺ signaling in the most important neurological disorders will then be considered.     

Melatonin,mitochondria, and the cancer cell

The long-recognized fact that oxidative stress within mitochondria is a hallmark of mitochondrial dysfunction has stimulated the development of mitochondria-targeted antioxidant therapies. Melatonin should be included among the pharmacological agents able to modulate mitochondrial functions in cancer, given that a number of relevant melatonin-dependent effects are triggered by targeting mitochondrial functions. Indeed, melatonin may modulate the mitochondrial respiratory chain, thus antagonizing the cancer highly glycolytic bioenergetic pathway of cancer cells. Modulation of the mitochondrial respiratory chain, together with Ca²⁺ release and mitochondrial apoptotic effectors, may enhance the spontaneous or drug-induced apoptotic processes. Given that melatonin may efficiently counteract the Warburg effect while stimulating mitochondrial differentiation and mitochondrial-based apoptosis, it is argued that the pineal neurohormone could represent a promising new perspective in cancer treatment strategy.     

Targeting O 6-methylguanine-DNA methyltransferase with specific inhibitors as a strategy in cancer therapy

O ⁶-methylguanine-DNA methyltransferase (MGMT) repairs the cancer chemotherapy-relevant DNA adducts, O ⁶-methylguanine and O ⁶-chloroethylguanine, induced by methylating and chloroethylating anticancer drugs, respectively. These adducts are cytotoxic, and given the overwhelming evidence that MGMT is a key factor in resistance, strategies for inactivating MGMT have been pursued. A number of drugs have been shown to inactivate MGMT in cells, human tumour models and cancer patients, and O ⁶-benzylguanine and O ⁶-[4-bromothenyl]guanine have been used in clinical trials. While these agents show no side effects per se, they also inactivate MGMT in normal tissues and hence exacerbate the toxic side effects of the alkylating drugs, requiring dose reduction. This might explain why, in any of the reported trials, the outcome has not been improved by their inclusion. It is, however, anticipated that, with the availability of tumour targeting strategies and hematopoetic stem cell protection, MGMT inactivators hold promise for enhancing the effectiveness of alkylating agent chemotherapy.     

Dual modes of 5-(N-ethyl-N-isopropyl)amiloride modulation of apical dipeptide uptake in the human small intestinal epithelial cell line Caco-2

Selective pharmacological Na⁺/H⁺ exchange (NHE) inhibitors were used to identify functional NHE isoforms in human small intestinal enterocytes (Caco-2) and to distinguish between direct and indirect effects on transport via the intestinal di/tripeptide transporter hPepT1. The relative potencies of these inhibitors to inhibit ²²Na⁺ influx identifies NHE3 and NHE1 as the apical and basolateral NHE isoforms. The Na⁺-dependent (NHE3-sensitive) component of apical dipeptide ([¹⁴C] Gly-Sar) uptake was inhibited by the selective NHE inhibitors with the same order of potency observed for inhibition of apical ²²Na⁺ uptake. However, 5-(N-ethyl-N-isopropyl) amiloride (EIPA) also reduced [¹⁴C]Gly-Sar uptake in the absence of Na⁺ and this inhibition was concentration and pH (maximal at pH 5.5) dependent. NHE3 inhibition by S1611 and S3226 modulates dipeptide uptake indirectly by reducing the transapical driving force (H⁺ electrochemical gradient). EIPA (at 100 μM) has similar effects, but at higher concentrations (>200 μM) also has direct inhibitory effects on hPepT1.Received 28 February 2005; received after revision 20 April 2005; accepted 20 May 2005     

Possible role of intestinal alkaline phosphatase activity in thiamine transport

Summary Thiamine deficiency caused a marked decrease of intestinal alkaline phosphatase (al-Pase) activity, but had no effect on the Ca⁺⁺-ATPase activity and Ca⁺⁺-absorption in rats. The al-Pase activity was significantly decreased 1 h after oral administration of ethanol at 0.5 and 2.5 g/kg. In contrast, Mg⁺⁺-, Ca⁺⁺- and (Na⁺+K⁺)-ATPase activities did not change after the administration of ethanol. These findings show that the al-Pase activity, unlike the Ca⁺⁺-ATPase activity, is not related to Ca⁺⁺-absorption. A possible role of al-Pase activity in the active transport of thiamine in the intestine was discussed.     

Effect of propylene glycol and ethanol on3H-noradrenaline efflux from an isolated blood vessel

Summary Propylene glycol (14 mM), but not ethanol (17 mM), enhanced the late phase of passive³H-efflux from rabbit isolated aortic rings preloaded with³H-(–)-noradrenaline. We conclude that, with regard to³H-noradrenaline release studies, propylene glycol is unsuitable for aiding the dissolution of e.g. corticosterone in physiological salt solution, while ethanol can be used for this purpose.This study was supported by the Danish Medical Research Council. The authors gratefully acknowledge the technical assistance of Miss Mariann Wolmar.     

Influence of ethanol on thyroxine accumulation in the hypothalamus,pituitary gland and cerebrospinal fluid in the newborn rabbit

Summary The effect of ethanol on thyroxine (T₄) accumulation in the hypothalamus (H), pituitary gland (P) and cerebrospinal fluid (CSF) has been investigated in 1–15-day-old rabbits. It has been found that H or CSF serum ratios decreased with age by about 2 in the course of 13 postnatal days. Stable T₄ resulted in an increase of¹²⁵I-T₄ in H, P and CSF. Ethanol per se caused an increase in transfer and accumulation of radiothyroxine or made the changes after loading animals with carrier T₄ more pronounced.     

Influence of ethanol on calcium,inositol phospholipids and intracellular signalling mechanisms

Summary Studies have implicated Ca⁺⁺ in the actions of ethanol at many biochemical levels. Calcium as a major intracellular messenger in the central nervous system is involved in many processes, including protein phosphorylation enzyme activation and secretion of hormones and neurotransmitters. The control of intracellular calcium, therefore, represents a major step by which neuronal cells regulate their activities. The present review focuses on three primary areas which influence intracellular calcium levels; voltage-dependent Ca⁺⁺ channels, receptor-mediated inositol phospholipid hydrolysis, and Ca⁺⁺/Mg⁺⁺-ATPase, the high affinity membrane Ca⁺⁺ pump.Current research suggests that a subtype of the voltage-dependent Ca⁺⁺ channel, the dihydropyridine-sensitive Ca⁺⁺ channel, is uniquely sensitive to acute and chronic ethanol treatment. Acute exposure inhibits, while chronic ethanol exposure increases⁴⁵Ca⁺⁺-influx and [³H]dihydropyridine receptor binding sites. In addition, acute and chronic exposure to ethanol inhibits, then increases Ca⁺⁺/Mg⁺⁺-ATPase activity in neuronal membranes. Changes in Ca⁺⁺ channel and Ca⁺⁺/Mg⁺⁺-ATPase activity following chronic ethanol may occur as an adaptation process to increase Ca⁺⁺ availability for intracellular processes. Since receptor-dependent inositol phospholipid hydrolysis is enhanced after chronic ethanol treatment, subsequent activation of protein kinase-C may also be involved in the adaptation process and may indicate increased coupling for receptor-dependent changes in Ca⁺⁺/Mg⁺⁺-ATPase activity.The increased sensitivity of three Ca⁺⁺-dependent processes suggest that adaptation to chronic ethanol exposure may involve coupling of one or more of these processes to receptor-mediated events.     

Pharmacological inhibition of store-operated calcium entry in MDA-MB-468 basal A breast cancer cells: consequences on calcium signalling,cell migration and proliferation

Store-operated Ca²⁺ entry is a pathway that is remodelled in a variety of cancers, and altered expression of the components of store-operated Ca²⁺ entry is a feature of breast cancer cells of the basal molecular subtype. Studies of store-operated Ca²⁺ entry in breast cancer cells have used non-specific pharmacological inhibitors, complete depletion of intracellular Ca²⁺ stores and have mostly focused on MDA-MB-231 cells (a basal B breast cancer cell line). These studies compared the effects of the selective store-operated Ca²⁺ entry inhibitors Synta66 and YM58483 (also known as BTP2) on global cytosolic free Ca²⁺ ([Ca²⁺]_CYT) changes induced by physiological stimuli in a different breast cancer basal cell line model, MDA-MB-468. The effects of these agents on proliferation as well as serum and epidermal growth factor (EGF) induced migration were also assessed. Activation with the purinergic receptor activator adenosine triphosphate, produced a sustained increase in [Ca²⁺]_CYT that was entirely dependent on store-operated Ca²⁺ entry. The protease activated receptor 2 activator, trypsin, and EGF also produced Ca²⁺ influx that was sensitive to both Synta66 and YM58483. Serum-activated migration of MDA-MB-468 breast cancer cells was sensitive to both store-operated Ca²⁺ inhibitors. However, proliferation and EGF-activated migration was differentially affected by Synta66 and YM58483. These studies highlight the need to define the exact mechanisms of action of different store-operated calcium entry inhibitors and the impact of such differences in the control of tumour progression pathways.     

Antidepressant drugs elevate rat pineal and plasma melatonin

Summary Acute administration in the mid-light phase of a number of antidepressant drugs of different pharmacological profiles elevated pineal and plasma melatonin (measured by radioimmunoassay). Following chronic treatment with the tricyclic antidepressant clomipramine, the elevation was significantly reduced. This may be an effect of reduced -adrenergic receptor sensitivity after chronic clomipramine administration, analogous to other findings of reduced -adrenergic receptor binding and reduced noradrenaline-sensitive adenylate-cyclase response.These collaborative studies were made possible by a Twinning Grant from the European Training Programme for Brain and Behaviour Research; J.A. was supported by the Medical Research Council of Great Britain. We thank M. Lichtsteiner for excellent technical assistance. This paper was written during a Fellowship of the Swiss Biomedical Research Foundation to A.W.-J. Hofmann-LaRoche AG, Basel kindly provided the 1-5HTP-ester (Ro 11-5940) and Ro 11-2465, CIBA-Geigy AG, Basel, the maprotiline, clomipramine, and imipramine, USV, New York, the desmethylimipramine.     

Influence of (-)3-hydroxy-N-propargyl-morphinan on the respiratory depressant action of codeine

Zusammenfassung Es wird festgestellt, dass Ro 1-7780 die atemdepressive Wirkung von Codein aufhebt. Die Dosis muss zweimal so gross wie die von Levallorphan sein. Das Dosisverhältnis zwischen Ro 1-7780 und Codein ist 1:50 bis 1:75.     

Ethanol as a ‘food’ forDrosophila melanogaster: Influence of theEbony gene

Summary The survival time of adultDrosophila melanogaster flies without food is greater in the presence of ethanol, especially for flies of strains or lines with a higher alcohol dehydrogenase activity. It seems that theebony gene can act in some populations as a selective factor favoring the ADH^F allele, as well as the minor genes enhancing the alcohol dehydrogenase activity level.Chargé de Recherches au F. N. R. S.     

A cannabinoid with cardiovascular activity but no overt behavioral effects

Summary Abnormal-⁸-tetrahydrocannabidiol (ABN-⁸-THC) failed to elicit central nervous system and cardiovascular effects in laboratory animals. Abnormal-cannabidiol (ABN-CBD) was also devoid of overt behavioral effects but produced marked hypotension with only slight bradycardia in anesthesized dogs.Acknowledgment. This work was supported by NIDA (grant No. DA-00574-01 and DA-00490) and Virginia Heart Society (grant No. RR-05697)     

Behavioral phenomenology of sleep (somatic and vegetative)

Conclusions The foregoing analysis of behavioral sleep phenomenology shows that the most significant factual and theoretical aspects of sleep can be logically organized only according to several criteria, it being impossible to choose a singli one as truly paradigmatic. For this reason an ordinal classification of sleep phases was preferred. This fact does not detract from the usefulness of classifications based consistently on 1 criterion at a time (e.g.: synchronized-desynchronized; quiet-active; orthodoxical-paradoxical; NREM-REM; homeostatic-poikilostatic; spindle wave-slow wave-fast wave; external appetitive-internal appetitive-internal consummatory; and so on). In this respect, the bioelectrical classification is surely the best as it allows an analytical subdivision of the evolution of sleep with high resolving power^137–139. In particular, the electroencephalographic activity of late phase II (stage 4 in man¹³⁹ and slow wave¹¹ or deep slow wave¹⁴⁰ sleep in the cat) appears to be related to the triggering mechanisms and to the quantitative regulation of the circadian amount of phase III^3,5,11,140. However, in extending the field of functional implications of sleep phenomenology other criteria may be more significant. In fact, the somatic and vegetative events of sleep also lend themselves to an analysis according to the behavioral model of ethology^6,141–144 and the theory of homeostasis^{3–5, 145}, respectively. As an example, a number of classifying criteria are indicated in the table, where others, particularly neurochemical ones^146,147, could be added. At any rate, the difficulty of organizing sleep events into a satisfactory operational scheme is due to the fact that sleep is still an open problem as far as its mechanisms and functional significance are concerned.     

Recombinant scorpine: a multifunctional antimicrobial peptide with activity against different pathogens

Scorpine is an antimicrobial peptide whose structure resembles a hybrid between a defensin and a cecropin. It exhibits antibacterial activity and inhibits the sporogonic development of parasites responsible for murine malaria. In this communication we report the production of scorpine in a heterelogous system, using a specific vector containing its cloned gene. The recombinantly expressed scorpine (RScp) in ^{Anopheles gambie} cells showed antibacterial activity against ^{Bacillus subtilis} and ^{Klebsiella pneumoniae}, at 5 and 10 μM, respectively. It also produced 98% mortality in sexual stages of ^{Plasmodium berghei} at 15 μM and 100% reduction in ^{Plasmodium falciparum} parasitemia at 5 μM. RScp also inhibited virus dengue-2 replication in C6/36 mosquito cells. In addition, we generated viable and fertile transgenic ^Drosophila that overexpresses and correctly secretes RScp into the insect hemolymph, suggesting that the generation of transgenic mosquitoes resistant to different pathogens may be viable. Received 6 May 2008; received after revision 24 July 2008; accepted 29 July 2008