[Illicit drugs, medications and traffic accidents]. / Drogues, médicaments et accidentologie.

The European Union (EU) has 25 member-states and 455 million inhabitants. Statistics on traffic accidents in the EU show that more than 45,000 people are killed annually, including 5200 in France. At the same time, nearly two million persons in the EU require medical treatment for traffic-accident-related injuries, including 109,000 in France. In addition, traffic accidents are the major cause of death of those individuals aged 15 to 24 years. One third of the EU inhabitants will be hospitalized during their life due to a traffic accident with a cost over 160 billion euro (2-3% of the Gross Domestic Product). An important contributing factor to crashes is the use of alcohol and/or illicit drugs or medication when driving, as they exert negative effects on cognition and psychomotor functions. For illicit drugs, abuse of cannabis with or without alcohol is a major concern for the EU. In fact, three million Europeans use cannabis daily and 80% of them drive after use. A number of French studies since 1999 have underlined the high prevalence of cannabis found in the blood of injured or killed drivers. From medical or judicial observations, it is clear that cannabis use increases the risk of traffic accidents. Many groups outside Europe have also shown the association between drug abuse and crashes. The number of casualties related to certain medicines, especially benzodiazepines remains at a high level, particularly in the elderly. In many countries the prevalence of medicinal drugs associated with car accidents is higher than with cannabis. Annex III of the European Union Council Directive of July the 29th 1991 in fact states that a driving license should not be issued to or renewed for applicants or drivers who are dependent on psychotropic substances or use them regularly. Recently, France has categorized the medicinal drugs available in the country by using three pictograms: level one yellow, "be careful"; level two orange, "be very careful"; level three red, "don't drive". It is an important campaign that increases awareness among the public and the medical professionals about the potential dangerous effects of medicinal drugs when driving. The EU objective of reducing the number of fatalities to 25,000 by 2010 will require strengthening measures against the use of alcohol, illicit and medicinal drugs by not well-informed drivers. It is not only a really great challenge, but also a significant investment towards improving public health in France as well as in Europe.

[The cannabis pandemic: why use this expression? Epidemiology]. / La pandémie cannabique : pourquoi cette expression ? Epidémiologie.

Using the term of pandemic to characterize the current use of cannabis is fully warranted considering the results of recent surveys [Halte au cannabis. Paris: Odile Jacob; 2006]. A pandemic is defined as an epidemic affecting populations in a very wide geographical zone which may involve one or several continents.

[Pharmacology, an innovative factor in therapeutic research]. / La pharmacologie, facteur d'innovation en recherche thérapeutique.

As members of the pharmacology training group set up by the committee of pharmacological science of the French Academy of Pharmacy, we examine the situation of pharmacology in drug discovery. Today, it is obvious that by integrating genome sequencing, cellular and molecular biology, and bioinformatics, pharmacology has become a cross-disciplinary science. Pharmacologists must become knowledgeable in a wide range of domains, using the major points in each to direct them towards the discovery and development of new therapeutic agents. It is also clear that pharmacology remains a major factor in the different steps of drug discovery, from the molecular and cellular stages, to clinical and pharmaceutical developments.

[Report of the "Health and Environment" commission of the National Academy of pharmacy. Carbon monoxide and environmental health: are carbon monoxide levels in urban areas a health hazard?]. / Le monoxyde de carbone CO et la santé environnementale: CO est-il nocif aux concentrations urbaines actuelles?

In an urban environment, carbon monoxide is produced by incomplete combustion, particularly in motor vehicles. Air pollution caused by CO produced by motor vehicles is controlled by legislation. Legal regulations have considerably lowered emission levels authorized for new vehicles and total CO emission levels. CO levels in the environment (urban environment in general and zones close to motorways) have thus declined. CO remains a public health concern both as a pollutant and as an indicator of air quality. We recall here the more recent approaches used to assess CO-related hazards developed by the Environmental Protection Agency in the United States and pertinent conclusions backing up previously defined reference levels. We then report recent French data concerning CO emission, environmental levels and evaluation procedures for different situations of human exposure: geographical situations, mode of transportation, police force, air sentinels. The third part of this article is devoted to biological data (interaction between CO and hemo-proteins, CO neurotransmitter?) and epidemiological data (serial surveys). The discussion centers on the limitations of epidemiological data and on the difficulty in evaluating hazards solely on the basis of a carboxyhemoglobin threshold. This latter point is particularly important because carboxyhemoglobin is only one of many indicators of air quality. Finally recommendations are proposed concerning weather-related aspects, evaluation of human exposure, and ways of improving biological and epidemiological data.

[New provisions for prevention and fight against doping]. / Nouvelles dispositions dans la prévention et la lutte contre le dopage.

Doping which is largely a sport-related phenomenon, led the French government of enact a series of laws in 1965, 1984, and 1989. Due to the apparent extension of doping, a new law was enacted on March 23, 1999. This law concerns medical surveillance of athletes and prevention and fight against doping. A council for the prevention and fight against doping was created. This nine-member council includes a representative of the French International Academy of Pharmacy and its president is a state counsellor. The council has three main areas of activity: disciplinary judgements concerning doped athletes, establishment of prevention policies, coordination of scientific research in the field of sport medicine and doping. The law also provides for penal sanctions for resellers. Antidoping activities are also managed on an international level. Contributors include the Council of Europe, the European Community, the International Olympic Committee, and the recently created (1999) World Antidoping Agency.

[Neuronal death: potential role of the nuclear enzyme, poly (ADP-ribose) polymerase]. / Mort neuronale: rôle potentiel d'une enzyme nucléaire, la poly(ADP-ribose) polymérase.

Poly(ADP-ribose) polymerase (PARP, EC 2.4.2.30) is known as a nuclear enzyme that is activated by DNA strand breaks to participate in DNA repair. It is also called poly(ADP-ribose) synthase (PARS) or poly(ADP-ribose) transferase (PADRT). In physiological conditions, PARP plays an important role in maintaining genomic stability. However, for several pathological situations, which include massive DNA injury (brain ischemia for example), excessive activation of PARP can deplete stores of nicotinamide adenine dinucleotide (NAD+), the PARP substrate, which, with the subsequent ATP depletion, leads to cell death. PARP activation appears to play a major role in neuronal death induced by cerebral ischemia, traumatic brain injury, Parkinson disease and other pathologies. PARP inhibitors (3-aminobenzamide and other compounds) and PARP gene deletion induced dramatic neuroprotection in experimental animals (rats, mice). Accordingly, these data suggest that PARP inhibitors could provide a novel therapeutic approach in a wide range of neurodegenerative disorders including cerebral ischemia and traumatic brain injury.

[Inefficacy of N-methyl-D-aspartate receptor complex antagonists on behavioral and histologic consequences of global cerebral ischemia in rats]. / Inefficacité des antagonistes du complexe réceptorial N-méthyl-D-aspartate à l'égard des conséquences comportementales et histologiques d'une ischémie cérébrale globale chez le rat.

Glutamic acid, an excitatory amino acid, has been proposed to play a major deleterious influence in cerebral ischemia. However, the neuroprotective activity of various glutamate receptor antagonists is often low or absent, according to the animal model used. In the present study, we examined the effect of several antagonists acting on glutamate receptors of the N-methyl-D-aspartate (NMDA) type in rats submitted to a brief (5 minutes) global cerebral ischemia. The different compounds used were poorly active or inactive on behavioural and histologic alterations induced by ischemia. Our results suggest that, in this model, overactivation of NMDA receptor complex does not play a predominant role in the pathogenesis of ischemic brain damage.

A microdialysis study investigating the mechanisms of hydroxyl radical formation in rat striatum exposed to glutamate.

Considerable evidence has linked hydroxyl radicals (.OH) to excitotoxicity. Glutamate infused through a microdialysis probe into rat striatum induced a massive .OH production, which was completely blocked by PBN and attenuated by dizocilpine, 2-amino-5-phosphonopentanoic acid (AP-5), NG-nitro-L-arginine methyl ester (L-NAME) and mepacrine. Thus, we suggest that the neurotoxic effects of glutamate in vivo may derive from an increased formation of .OH resulting from excessive activation of NMDA receptors and downstream enzymes such as NOS and PLA2.

iNOS contribution to the NMDA-induced excitotoxic lesion in the rat striatum.

1. The aim of this study was to assess whether an excitotoxic insult induced by NMDA may induce an iNOS activity which contributes to the lesion in the rat striatum. 2. For this purpose, rats were perfused with 10 mM NMDA through a microdialysis probe implanted in the left striatum. Microdialysate nitrite content, striatal Ca-independent nitric oxide synthase activity and lesion volume were measured 48 h after NMDA exposure in rats treated with dexamethasone (DXM) (3 mg kg(-1) x 4) or aminoguanidine (AG) (100 mg kg(-1) x 4). 3. A significant increase in microdialysate nitrite content and in the Ca-independent NOS activity was observed 48 h after NMDA infusion. Both these increases were reduced by DXM and AG. The NMDA-induced striatal lesion was also reduced by both treatments. 4. Our results demonstrate that NMDA excitotoxic injury induces a delayed, sustained activation of a Ca-independent NOS activity. This activity is blocked by DXM and AG, strongly suggesting the involvement of iNOS. The fact that AG and DXM reduce the NMDA-elicited lesion suggests that iNOS contributes to the brain damage induced by excitotoxic insult.

[Behavioral and neurochemical methods in research on new psychotropics]. / Méthodes comportementales et neurochimiques dans la recherche des nouveaux psychotropes.

Since the discovery of the antipsychotic effects of chlorpromazine by the French psychiatrists DELAY and DENIKER in 1952, preclinical pharmacologists have proposed several laboratory tests, that have been used to demonstrate the potential activity of drugs in the treatment of mental disorders including schizophrenia, depressive illness and anxiety. Tests are divided into behavioural tests and neurochemical tests. Electrophysiology tests are not considered in this paper. Concerning schizophrenia, although there is no valid model, behavioural tests presently used are: antagonism against various responses induced by dopamine receptor agonists, inhibition of conditioned behaviours, latent inhibition, startle reaction, models related to the neurodevelopmental hypothesis. For antidepressant activity, models are based on antagonism of various effects of reserpine. More anthropomorphic models involve helplessness behaviours, social isolation, changes induced by limbic system lesions. Biochemical investigations mainly involve in vitro and in vivo tests: study of changes in the metabolism of neurotransmitters using microdialysis and other procedures, interaction with receptor subtypes. As a result of advances in molecular biology, other tools are now emerging, but classical tests remain useful.

Protective effect of melatonin in a model of traumatic brain injury in mice.

The pineal hormone melatonin has recently been shown to exert neuroprotective activity in a variety of experimental neuropathologies in which free radicals are involved. This neuroprotective effect has been attributed to the antioxidant properties of melatonin. Considering that free radicals also play a deleterious role in traumatic brain injury (TBI), the purpose of the present study was to determine whether melatonin would have a beneficial effect in this pathology. Head injury was induced in mice and the neurological deficit was evaluated at 24 hr by a grip test. In this model, the free radical scavenger, alpha-phenyl-tert-butyl-nitrone (2 x 100 mg/kg, i.p.) given 5 min and repeated at 4 hr after TBI was neuroprotective. Melatonin (1.25 mg/kg, i.p.) given 5 min and repeated at 1, 2, and 3 hr after head trauma also significantly reduced the neurological deficit. This beneficial effect was not due to melatonin-induced hypothermia since repeated treatment with melatonin did not modify the colonic temperature of mice. This study shows that melatonin exerts a beneficial effect on the neurological deficit induced by traumatic brain injury in mice. The mechanisms of this neuroprotection remains to be established, and more particularly, the contribution of the antioxidant activity of melatonin.

Reduction of tyrosine nitration after N(omega)-nitro-L-arginine-methylester treatment of mice with traumatic brain injury.

Oxygen free radicals and nitric oxide (NO) have been proposed to be involved in the cascade of injury elicited by traumatic brain injury. However, the mechanism(s) of injury remain to be explored. Since superoxide generation is triggered by traumatic brain injury, the cytotoxic peroxynitrite could be formed, but it is not known if this actually occurs. Dot blot and immunohistochemistry studies were performed to quantify tyrosine nitration and identify cell types in which such reactions occur in the brain of mice submitted to traumatic brain injury. Nitrotyrosine formation increased from 4 to 24 h after traumatic brain injury and was primarily observed in degenerating neurons, in areas corresponding to the sites of direct impact (frontal cortex) and diffuse impact (frontoparietal cortex and ventromedial hypothalamic nucleus). Furthermore, N omega-nitro-L-arginine-methylester (L-NAME), a NO-synthase inhibitor which has previously been shown to promote neurological recovery in traumatic brain injury, reduced nitrotyrosine formation and the number of nitrotyrosine-positive neurons. These results indicate that traumatic brain injury induces peroxynitrite formation which may contribute to cell damage.

Glutamate induces hydroxyl radical formation in vivo via activation of nitric oxide synthase in Sprague-Dawley rats.

It was recently reported that neuronal nitric oxide synthase (NOS) generates oxygen-derived free radicals in vitro at low concentrations of L-arginine. Using the microdialysis technique, we monitored both hydroxyl radical (.OH) and nitric oxide (.NO) formation in rat striatum perfused with glutamate (500 mM). .OH and .NO were quantitated in microdialysates by measuring the amounts of the non-enzymatic hydroxylation product of salicylate (2,3-dihydroxybenzoic acid) and the metabolites of .NO (nitrite + nitrate), respectively. .OH levels were dramatically increased during glutamate perfusion, while .NO generation was virtually abolished. .OH production was inhibited by the specific NOS blocker, NG-nitro-L-arginine methyl ester. This effect was not reversed but potentiated by L-arginine. Thus, it is likely that NOS generates oxygen-derived free radicals instead of .NO in brain subjected to highly excitotoxic conditions.

Deleterious Ca-independent NOS activity after oxidative stress in rat striatum.

The aim of this study was to assess whether oxidative stress induces deleterious NOS activity in the central nervous system (CNS). For this purpose, the mitochondrial toxin malonate, which promotes free radical production, was infused into the left striatum of rats. Forty-eight hours after injection, an increase in Ca-independent NOS activity was observed in the injected striatum. This increase was blocked by alpha-phenyl-tert-butyl-nitrone, a free radical scavenger, and by aminoguanidine, an inhibitor of NOS 2. Both these drugs reduced the malonate-induced striatal necrotic volume. These results suggest that in the CNS oxidative stress can induce a Ca-independent NOS, probably of type 2, which contributes to the lesion.

[Behavioral and neurochemical methods in research on new psychotropic drugs]. / Méthodes comportementales et neurochimiques dans la recherche des nouveaux psychotropes.

Since the discovery of the antipsychotic effects of chlorpromazine by the french psychiatrists Delay and Deniker in 1952, preclinical pharmacologists have proposed several laboratory tests, that have been used to demonstrate the potential activity of drugs in the treatment of mental disorders including schizophrenia, depressive illness and anxiety. Tests are divided into behavioural tests and neurochemical tests. Electrophysiology tests are not considered in this paper. Concerning schizophrenia, in spite that there is no valid model, behavioural tests presently used are: antagonism against various responses induced by dopamine receptor agonists, inhibition of conditioned behaviours, latent inhibition, startle reaction, models related to the neurodevelopmental hypothesis. For antidepressant activity, models are based on antagonism of various effects of reserpine. More anthropomorphic models involve helplessness behaviours, social isolation, changes induced by limbic system lesions. Biochemical investigations mainly involve in vitro and in vivo tests: study of changes in the metabolism of neurotransmitters using microdialysis and other procedures, interaction with receptor subtypes. As a result of advances in molecular biology, other tools are now emerging, but classical tests remain useful.

alpha-Phenyl-N-tert-butylnitrone attenuates excitotoxicity in rat striatum by preventing hydroxyl radical accumulation.

Various in vitro experiments have indicated that oxygen-derived free radicals may contribute to excitotoxic neuronal death. In the present study we induced excitotoxicity in rat striatum by perfusing glutamate at a high concentration through a microdialysis probe. We observed an increased formation of hydroxyl radicals (.OH) during the perfusion of the excitotoxin and an extensive striatal lesion 24 h after the insult. The spin trap, alpha-phenyl-N-tert-butylnitrone (PBN), attenuated both hydroxyl radical levels and the volume of the lesion. This result suggests that the neuroprotection may be due to a free radical scavenging mechanism. It also implies that PBN may be used in pathological situations involving excitotoxicity such as stroke, brain trauma, and chronic neurologic diseases.

Dose- and time-dependence of L-NAME neuroprotection in transient focal cerebral ischaemia in rats.

1. In this study the effect of the dose and administration time of NG-nitro-L-arginine methyl ester (L-NAME), an NO-synthase inhibitor, in a model of transient focal cerebral ischaemia in rats was investigated. 2. Two injections of L-NAME were given, of 1, 3 and 10 mg kg-1, 5 min and 3 h after the onset of ischaemia. None of the doses gave any striatal neuroprotection, but 1 and 3 mg kg-1 L-NAME reduced the infarcted volume in the cortex (by 26%, P < 0.01 for 1 mg kg-1 and 21%, P < 0.05 for 3 mg kg-1), whereas 10 mg kg-1 had no neuroprotective effect. 3. Single injections of L-NAME 1 mg kg-1, given 5 min or 3 h after ischaemia onset, had similar neutoprotective effects on the cortical infarction as did the repeated injections. 4. L-NAME 1 mg kg-1 given 3, 6 or 9 h after ischaemia induction reduced the cortical infarct volume by 19% (P < 0.01) when given 3 h after ischaemia, by 21% (P < 0.01) when given at 6 h, and by 16% (P < 0.05) when given at 9 h, but had no neuroprotective activity when given 12 h after ischaemia. 5. Thus a low dose of L-NAME is neuroprotective in a model of transient focal ischaemia, with a wide therapeutic window, much larger than that found or MK-801.

Calcium-independent NO-synthase activity and nitrites/nitrates production in transient focal cerebral ischaemia in mice.

1. The temporal changes in constitutive NO-synthase (cNOS) and in calcium-independent NO-synthase activities were studied in mice subjected to 2 h of transient focal cerebral ischaemia. The changes in brain nitrites/nitrates (NOx) content were also studied. 2. NOS activities were measured by the conversion of L-[14C]-arginine to L-[14C]-citrulline. Brain NOx contents were investigated by the Griess colourimetric method. 3. cNOS activity in the infarcted cortical area was significantly reduced after 6 h of reperfusion and this activity remained attenuated for up to 10 days after ischaemia. A calcium-independent NOS activity began to increase 48 h after reperfusion, reached a maximum at 7 days and returned to baseline at 10 days. 4. There was a significant increase of brain NOx content beginning after 3 days of reperfusion. This increase was maximal at 7 days and returned to baseline at 10 days. 5. Thus, ischaemia followed by recirculation leads to a rapid, prolonged drop in cNOS activity in the infarcted cortex. There is also a substantial appearance of calcium-independent NOS activity in the later phase of transient ischaemia, leading to an important increase of NOx production.