Porsolt and Partners Pharmacology

Sainte-Foy-lès-Lyon, France

Porsolt and Partners Pharmacology

Sainte-Foy-lès-Lyon, France

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Kalk P.,Charité - Medical University of Berlin | Kalk P.,Institute of Pharmacology | Sharkovska Y.,Institute of Pharmacology | Sharkovska Y.,University of Potsdam | And 16 more authors.
Hypertension | Year: 2011

Hypertensive heart disease is a major contributor to cardiovascular mortality. Endothelin is a potent vasoconstrictive and profibrotic mediator produced by the endothelin-converting enzyme (ECE), whereas natriuretic peptides, degraded by the neutral endopeptidase (NEP), have diuretic, vasodilatory, and antifibrotic properties. Thus, combined ECE/NEP inhibition may halt hypertensive cardiac remodeling. This study examined effects of SLV338, a novel ECE/NEP inhibitor, on cardiac protection in experimental renovascular hypertension (2-kidney, 1-clip [2K1C]). Male rats were allocated to 5 groups: sham-operated rats, untreated animals with 2K1C, 2K1C animals treated with oral SLV338 (30 and 100 mg/kg per day), and 2K1C animals treated with oral losartan (20 mg/kg per day). Treatment duration was 12 weeks. Blood pressure was assessed every 4 weeks. At study end, hearts were taken for histology/computer-aided histomorphometry/immunohistochemistry. Pharmacological properties of SLV338 are described. SLV338 is a dual ECE/NEP inhibitor, as demonstrated both in vitro and in vivo. In the 2K1C study, losartan lowered blood pressure by ≤46 mm Hg, whereas both dosages of SLV338 had no effect. However, SLV338 (both dosages) completely normalized cardiac interstitial fibrosis, perivascular fibrosis, myocyte diameter, and media:lumen ratio of cardiac arteries, as did losartan. Cardiac transforming growth factor-β1 expression was significantly enhanced in untreated 2K1C rats versus controls, whereas treatment with SLV338 and losartan prevented this effect. Taken together, dual ECE/NEP inhibitor SLV338 prevents cardiac remodeling to the same extent as losartan, but in a blood pressure-independent manner, in a rat model of renovascular hypertension. This effect is at least partially mediated via suppression of cardiac transforming growth factor-β1 expression. Copyright © 2011 American Heart Association. All rights reserved.


Moser P.,Porsolt and Partners Pharmacology | Wolinsky T.,Porsolt and Partners Pharmacology | Duxon M.,Porsolt and Partners Pharmacology | Porsolt R.D.,Porsolt and Partners Pharmacology
Journal of Pharmacology and Experimental Therapeutics | Year: 2011

Nonclinical assessment of drug abuse and dependence is the subject of several recent regulatory guidelines, which are generally aligned on the methods to be employed. The most direct approach to assessing reinforcing properties of a drug is the self-administration procedure whereby animals can initiate intravenous injections of the test substance, something they readily do with prototypic drugs of abuse. Complications arise because there is no standardized procedure for evaluating substances with differing potencies, reinforcement properties, or pharmacokinetics. Moreover, the choice of training substance, species, and procedural parameters can radically affect the outcome. Apart from the lower cost of rats, primates present several advantages for self-administration studies with similarity to human pharmacokinetics in particular. The most powerful method for assessing similarities between a test substance and a prototypic drug of abuse is the drug discrimination procedure. In contrast to self-administration, drug discrimination is pharmacologically very specific, often reflecting functional activity at receptor level. Dependence is assessed by the occurrence of withdrawal effects on drug discontinuation. Although conceptually simple, interpretation can be complicated by factors such as duration and frequency of administration and observations as well as the choice of end points. Telemetry allows continuous observation of multiple parameters during withdrawal, thereby increasing sensitivity. Presently available tools identify all substances known to cause abuse or dependence, with little risk of false-positives. It remains unclear, however, how predictive these models are with entirely novel substances. Nonetheless, drug abuse/dependence is an area of safety pharmacology where the predictive value of animal models is remarkably high. Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics.


Picard S.,University of Caen Lower Normandy | Goineau S.,Porsolt and Partners Pharmacology | Guillaume P.,Porsolt and Partners Pharmacology | Henry J.,University of Caen Lower Normandy | And 2 more authors.
Cardiovascular Toxicology | Year: 2011

Safety Pharmacology studies for the cardiovascular risk assessment, as described in the ICH S7A and S7B guidelines, appear as being far from sufficient. The fact that almost all medicines withdrawn from the market because of life-threatening tachyarrhythmias (torsades-de-pointes) were shown as hERG blockers and QT interval delayers led the authorities to focus mainly on these markers. However, other surrogate biomarkers, e.g., TRIaD (triangulation, reverse-use-dependence, instability and dispersion of ventricular repolarization), have been identified to more accurately estimate the drug-related torsadogenic risk. In addition, more attention should be paid to other arrhythmias, not related to long QT and nevertheless severe and/or not self-extinguishing, e.g., atrial or ventricular fibrillation, resulting from altered electrical conduction or heterogeneous shortening of cardiac repolarization. Moreover, despite numerous clinical cases of drug-induced pulmonary hypertension, orthostatic hypotension, or heart valvular failure, few safety investigations are still conducted on drug interaction with cardiac and regional hemodynamics other than changes in aortic blood pressure evaluated in conscious large animals during the core battery mandatory studies. This critical review aims at discussing the usefulness, relevance, advantages, and limitations of some preclinical in vivo, in vitro, and in silico models, with high predictive values and currently used in supplemental safety studies. © 2011 Springer Science+Business Media, LLC.


Porsolt R.D.,Porsolt and Partners Pharmacology | Moser P.C.,Porsolt and Partners Pharmacology | Castagne V.,Porsolt and Partners Pharmacology
Journal of Pharmacology and Experimental Therapeutics | Year: 2010

Schizophrenia is characterized by three major symptom classes: positive symptoms, negative symptoms, and cognitive deficits. Classical antipsychotics (phenothiazines, thioxanthenes, and butyrophenones) are effective against positive symptoms but induce major side effects, in particular, extrapyramidal symptoms (EPS). The discovery of clozapine, which does not induce EPS and is thought effective against all three classes of symptom, has driven research for novel antipsychotics with a wider activity spectrum and lower EPS liability. To increase predictiveness, current efforts aim to develop translational models where direct parallels can be drawn between the processes studied in animals and in humans. The present article reviews existing procedures in animals for their ability to predict compound efficacy and EPS liability in relation to their translational validity. Rodent models of positive symptoms include procedures related to dysfunction in central dopamine and glutamatergic (N-methyl-D-aspartate) and serotonin (5-hydroxytryptamine) neurotransmission. Procedures for evaluating negative symptoms include rodent models of anhedonia, affective flattening, and diminished social interaction. Cognitive deficits can be assessed in rodent models of attention (prepulse inhibition) and of learning/memory (object and social recognition, Morris water maze and operant-delayed alternation). The relevance of the conditioned avoidance response is also discussed. A final section reviews procedures for assessing EPS liability, in particular, parkinsonism (catalepsy in rodents), acute dystonia (purposeless chewing in rodents, dystonia in monkeys), akathisia (defecation in rodents), and tardive dyskinesia (long-term antipsychotic treatment in rodents and monkeys). It is concluded that, with notable exceptions (attention, learning/ memory, EPS liability), current predictive models for antipsychotics fall short of clear translational validity. Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics.


PubMed | Porsolt and Partners Pharmacology
Type: | Journal: Current protocols in pharmacology | Year: 2012

The vigilance-controlled quantified EEG can be used either as a safety, or as a discovery pharmacology procedure. Put strategically into the preclinical development process of a drug, it can be useful for making the decision about the future research direction to be taken. The experimental approach described in this unit is based on the rat EEG. Even though there are considerable differences in function and structure between human and rat brain, the EEG response to psychoactive drugs and convulsants is similar in the two species. Thus, the rat EEG is generally a reliable predictor for human CNS drug effects.


PubMed | Porsolt and Partners Pharmacology
Type: | Journal: Current protocols in pharmacology | Year: 2012

Abnormalities of cardiac rhythm are one of the most common clinical problems in cardiology and arise as the result of either disorders of cardiac impulse formation or conduction, or a combination of both. It has been established that some classes of drugs, such as tricyclic antidepressants (e.g., imipramine), cardiac glycosides (e.g., digoxin), and Class I or Class III antiarrhythmic drugs (e.g., quinidine or amiodarone) can produce electrocardiographic toxicity in humans. It is therefore highly advisable to assess the effect of any new compound in this respect, during the early phases of drug development. This unit presents a protocol to detect the electrocardiographic toxicity of compounds in the anesthetized guinea pig.


PubMed | Porsolt and Partners Pharmacology
Type: | Journal: Current protocols in pharmacology | Year: 2012

Conditioned place preference is a behavioral model currently used to measure the rewarding properties induced by the administration of a drug. In this paradigm, the rewarding properties of a compound are associated with the particular characteristics of a given environment. Advantages of this test are the absence of any instrumental learning and the possibility of evaluating reinforcing effects in the absence of the test substance. Due to the recent availability of multiple lines of genetically modified mice, this unit has been updated to include procedures for testing place preference in both rats and mice. Details are also provided for evaluating drug effects using this procedure.


PubMed | Porsolt and Partners Pharmacology
Type: | Journal: Current protocols in pharmacology | Year: 2012

The proarrhythmic potential of new chemical entities can be investigated using in vitro electrophysiological techniques measuring the cardiac action potential in isolated Purkinje fibers. Different types of arrhythmias may occur as early afterdepolarizations (EADs), which are favored by action potential duration lengthening and bradycardia, or as delayed afterdepolarizations (DADs), which are facilitated by tachycardia. The effects of a test compound on the occurrence of these arrhythmias, thought to be responsible for the development of torsades de pointes in the clinic can be studied using the experimental protocols described in this unit.


PubMed | Porsolt and Partners Pharmacology
Type: | Journal: Current protocols in pharmacology | Year: 2012

The protocols described in this unit are designed to assess the effects of substances on intestinal transit and gastric emptying and to evaluate their ulcerogenic potential on the stomach and duodenum of the rat. Examples of results obtained with atropine or morphine (intestinal transit), loperamide (gastric emptying), or indomethacin (ulcerogenic activity) used as reference substances are provided for illustrative purposes. Atropine and morphine clearly reduce intestinal transit. Atropine, morphine, and loperamide clearly reduce gastric emptying. Indomethacin shows a marked ulcerogenic potential.


PubMed | Porsolt and Partners Pharmacology
Type: | Journal: Current protocols in pharmacology | Year: 2012

Postural-change-induced (orthostatic) hypotension is defined as an excessive drop in arterial blood pressure occurring when moving toward an upright position. This side effect, which may limit the therapeutic use of some agents, can occur with drugs, such as adrenoceptor blockers and vasodilators, that dampen sympathetic reflex activity. Described in this unit is a procedure for evaluating the effects of test substances on the changes in blood pressure and heart rate that occur in an anesthetized, normotensive rat during a tilting challenge (head-up position). In addition to being a relatively simple technique, this assay yields reproducible orthostatic hypotensive responses and allows for the investigation, in the same preparation, of several ascending doses of a test substance. Examples of results obtained with prazosin, an 1-adrenoceptor antagonist that is notorious for causing orthostatic hypotension, are provided for illustrative purposes.

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