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P Lacroix

Publications and source records attributed to P Lacroix.

107 records · Page 6Linked to original sources
PubMedDate not supplied

In vivo 31P NMR assessed effects of dantrolene on mechanics and energy metabolism in tetanic stimulated rat gastrocnemius.

Dantrolene does not affect fatigue from submaximal effort and MVC while it decreases twitch tension. We hypothesize that dantrolene could modify the relation between energy metabolism and fatigue by inhibiting calcium release from the sarcoplasmic reticulum. The effects of dantrolene (10 mg) on mechanical and metabolic parameters of gastrocnemius muscle were examined by 31P NMR during an in vivo fatigue test. The fatigue test constituted of three successive 20 min periods of increased stimulation rhythms and followed by a 20 min recovery period. 31P NMR was used to determine phosphocreatine (PCr), ATP and intracellular pH changes, while tension was recorded. We showed that dantrolene increased mechanical fatigue while PCr levels were similar to those from control animals. Acidosis was most prominent in dantrolene treated rats. These results suggest that dantrolene firstly affects calcium cycling with additive effects to fatigue and, secondly, modifies the activation of oxidative metabolism and the energy cost of the generated tension.

Adenosine Triphosphate↗
PubMedDate not supplied

Potential biological targets for anti-Alzheimer drugs.

The stunning accumulation of data on the physiopathology of Alzheimer's disease is a real hinderance to pharmacologists who have to make decisions as to what molecules should be assessed first in man. Considering the cumbersomeness and cost of clinical trials in that field, a review of potential targets for drugs that are supposed to be active against the disease has become necessary, for a true definition of the rational justifications of trials to be envisaged.

Alzheimer Disease↗
PubMedDate not supplied

Basic safety pharmacology: the cardiovascular system.

The cardiovascular system is one of the primary vital functions which have to be examined during safety pharmacology studies. Cardiovascular system functioning is maintained by cardiac electrical activity and by pump-muscle function which contribute to haemodynamic efficacy. The aim of cardiovascular safety pharmacology is to evaluate the effects of test substances on the most pertinent components of this system, in order to detect potentially undesirable effects, before engaging in clinical trials. In the basic programme, a detailed haemodynamic evaluation is carried out in the anaesthetized dog. It is completed by cardiac and/or cellular electrophysiology investigations in order to assess the arrhythmogenic risk. The basic programme can be preceded by rapid and simple testing procedures, during the early drug discovery stage. It should be completed, if necessary, by specific supplementary studies, depending on the data obtained during the early clinical trials. The following article describes and presents an analytic strategy aimed at problems of cardiovascular risk.

Animals↗
PubMedDate not supplied

[Acute dissection of the infrarenal aorta and horseshoe kidney. Apropos of a case and review of the literature].

We report about one case of acute dissection of the infrarenal abdominal aorta associated with a horseshoe kidney. A few points in the history of this 47-year-old patient deserve being underscored: the absence of an "etiological" factor of aortic dissection, the presence of five renal arteries, illustrating the complex vascularity of a horseshoe kidney, the specific surgical problems arising from both a lesion of the aortic junction and a horseshoe kidney. On the basis of the literature, we underline the incidence of dissection of the infrarenal aorta (1 to 3%), that of horseshoe kidney (0.15%) and that of pathology of the aortic junction in patients with a horseshoe kidney, which seems to be accidental.

Aortic Dissection↗
PubMedDate not supplied

[Effects of co-administration of an antidepressant and an anxiolytic drug in the "learned helplessness" paradigm: importance of hydroxyzine].

Whereas benzodiazepines are routinely coadministered with tricyclic antidepressants, in patients undergoing treatment for depressive disorders, little information is known about the combination of benzodiazepines with other antidepressants such as specific serotonin reuptake inhibitors (SSRI's), and combination with other anxiolytic drugs. On the other hand, it is known that benzodiazepines decrease the serotoninergic transmission. The present study was undertaken to evaluate the effect of concomittant administration of anxiolytic drugs such as benzodiazepines (diazepam, lorazepam) or diphenylmethane derivative (hydroxyzine) with specific serotonin reuptake inhibitors, (fluvoxamine, fluoxetine, indalpine) on the ability of antidepressant drugs to reverse helpless behavior in this test. Our results show that: daily injection of diazepam (0.25-2 mg/kg), lorazepam (0.06-0.25 mg/kg) or hydroxyzine (8.32 mg/kg) failed to reverse the behavioral deficit in rat. In contrast fluvoxamine: 4 mg/kg/day; fluoxetine: 4 mg/kg/day; indalpine: 1 mg/kg/day significantly reverse the helpless behavior in this test; the reversal of helpless behavior by fluvoxamine or indalpine was dose-dependently antagonized by daily coadministration of diazepam or lorazepam; in contrast, the reversal of helpless behavior by fluvoxamine or fluoxetine was not modified by daily coadministration of hydroxyzine (8 mg/kg). In conclusion, it may be suggested that combined benzodiazepine-specific serotonin reuptake inhibitors, should be avoided. We suggest that anxiolytic drugs such as hydroxyzine might be better in coadministration with antidepressants, particularly with specific serotonin reuptake inhibitors.

Animals↗