Depolarization and neurotrophins converge on the phosphatidylinositol 3-kinase-Akt pathway to synergistically regulate neuronal survival

In this report, we have examined the mechanisms whereby neurotrophins and neural activity coordinately regulate neuronal survival, focussing on sympathetic neurons, which require target-derived NGF and neural activity for survival during development. When sympathetic neurons were maintained in suboptimal concentrations of NGF, coincident depolarization with concentrations of KCl that on their own had no survival effect, synergistically enhanced survival. Biochemical analysis revealed that depolarization was sufficient to activate a Ras-phosphatidylinositol 3-kinase-Akt pathway (Ras-PI3-kinase-Akt), and function-blocking experiments using recombinant adenovirus indicated that this pathway was essential for approximately 50% of depolarization-mediated neuronal survival. At concentrations of NGF and KCl that promoted synergistic survival, these two stimuli converged to promote increased PI3-kinase-dependent Akt phosphorylation. This convergent PI3-kinase-Akt pathway was essential for synergistic survival. In contrast, inhibition of calcium/calmodulin-dependent protein kinase II revealed that, while this molecule was essential for depolarization-induced survival, it had no role in KCl- induced Akt phosphorylation, nor was it important for synergistic survival by NGF and KCl. Thus, NGF and depolarization together mediate survival of sympathetic neurons via intracellular convergence on a Ras-PI3-kinase-Akt pathway. This convergent regulation of Akt may provide a general mechanism for coordinating the effects of growth factors and neural activity on neuronal survival throughout the nervous system.

Cannabis in sport: anti-doping perspective

Since 2004, when the World Anti-Doping Agency assumed the responsibility for establishing and maintaining the list of prohibited substances and methods in sport (i.e. the Prohibited List), cannabinoids have been prohibited in all sports during competition. The basis for this prohibition can be found in the World Anti-Doping Code, which defines the three criteria used to consider banning a substance. In this context, we discuss the potential of cannabis to enhance sports performance, the risk it poses to the athlete's health and its violation of the spirit of sport. Although these compounds are prohibited in-competition only, we explain why the pharmacokinetics of their main psychoactive compound, Δ(9)-tetrahydrocannabinol, may complicate the results management of adverse analytical findings. Passive inhalation does not appear to be a plausible explanation for a positive test. Although the prohibition of cannabinoids in sports is one of the most controversial issues in anti-doping, in this review we stress the reasons behind this prohibition, with strong emphasis on the evolving knowledge of cannabinoid pharmacology.

The list of prohibited substances and methods in sport: structure and review process by the world anti-doping agency

The List of Prohibited Substances and Methods (the List) is the International Standard that determines what is prohibited in sport in- and out-of-competition. The official text of the List is produced by the World Anti-Doping Agency (WADA), the international independent organization responsible for promoting, coordinating and monitoring the fight against doping in sport. The drafting of the annual List is a highly interactive and consultative process involving scientific and medical experts in anti-doping, sport federations and governments. In this article, the elements that compose the List as well as the process behind its annual revision and update are presented.

Determination of urinary concentrations of pseudoephedrine and cathine after therapeutic administration of pseudoephedrine-containing medications to healthy subjects: implications for doping control analysis of these stimulants banned in sport

Due to its stimulatory effects on the central nervous system, and its structural similarity to banned stimulants such as ephedrine and methamphetamine, pseudoephedrine (PSE) at high doses is considered as an ergogenic aid for boosting athletic performance. However, the status of PSE in the International Standard of the Prohibited List as established under the World Anti-Doping Code has changed over the years, being prohibited until 2003 at a urinary cut-off value of 25 µg/ml, and then subsequently removed from the Prohibited List during the period 2004-2009. The re-consideration of this position by the World Anti-Doping Agency (WADA) List Expert Group has led to the reintroduction of PSE in the Prohibited List in 2010. In this manuscript, we present the results of two WADA-sponsored clinical studies on the urinary excretion of PSE and its metabolite cathine (CATH) following the oral administration of different PSE formulations to healthy individuals at therapeutic regimes. On this basis, the current analytical urinary threshold for the detection of PSE as a doping agent in sport has been conservatively established at 150 µg/ml

A novel approach to improve detection of glucocorticoid doping in sport with new guidance for physicians prescribing for athletes

The systemic effect of glucocorticoids (GCs) following injectable routes of administration presents a potential risk to both improving performance and causing harm to health in athletes. This review evaluates the current GC antidoping regulations defined by the World Anti-Doping Agency and presents a novel approach for defining permitted and prohibited use of glucocorticoids in sport based on the pharmacological potential for performance enhancement (PE) and risk of adverse effects on health. Known performance-enhancing doses of glucocorticoids are expressed in terms of cortisol-equivalent doses and thereby the dose associated with a high potential for PE for any GC and route of administration can be derived. Consequently, revised and substance-specific laboratory reporting values are presented to better distinguish between prohibited and permitted use in sport. In addition, washout periods are presented to enable clinicians to prescribe glucocorticoids safely and to avoid the risk of athletes testing positive for a doping test.

Structure and Development of the List of Prohibited Substances and Methods

The list of prohibited substances and methods (the List) is the international standard that determines what is prohibited in sport both in- and out-of-competition. Since 2004, the official text of the List is produced by the World Anti-Doping Agency (WADA), the international independent organization responsible for promoting, coordinating, and monitoring the fight against doping in sport. Originally based on the prohibited lists established by the International Olympic Committee, the List has evolved to incorporate new doping trends, distinguish permitted from prohibited routes of administration, and adjust to new analytical and pharmacological breakthroughs. In this chapter, the elements that compose the List as well as the updates over the years are presented.

Investigating the use of stimulants in out-of-competition sport samples

The List of Prohibited Substances and Methods (the List), an International Standard published yearly by the World Anti-Doping Agency (WADA), determines which substances and methods are prohibited in sport in- and out-of-competition. Stimulants are included within drug class S.6 under the in-competition testing section of the List. Athletes may be tempted to use stimulants as ergogenic aids in-competition in order to temporarily improve their mental and/or physical functions by increasing alertness, aggressiveness, motivation, locomotion, heart rate, and reducing fatigue. The Prohibited List Expert Group, responsible for the maintenance of the List, approved WADA funding for a two-year study to determine whether athletes were also using stimulants to benefit from their performance-enhancing effects during the training phase between competitions (i.e., out-of-competition). This study, involving 11 WADA-accredited laboratories, found that the use of stimulants by athletes during training was not significantly prevalent (0.36% of positive findings), suggesting that this issue does not, at the moment, pose a further challenge to the fight against doping in sport. In addition, the study supports the current structure in the Prohibited List that differentiates banned substances into the in- and out-of-competition classifications.

Interovarian relationship in the secretion of progesterone during the luteal phase of the capuchin monkey (Cebus apella)

In basal conditions, progesterone concentrations were similar in the ovarian veins of the ovary +CL (3211 +/- 526 ng/ml) and the ovary -CL (3165 +/- 554 ng/ml), but after blocking the blood flow between the ovary +CL and the uterus, the progesterone values in the vein draining the ovary -CL decreased to 1218 +/- 394 ng/ml (P less than 0.01). When [3H]progesterone was injected in the ovary +CL, the radioactivity appeared earlier and more concentrated in the vein draining the ovary -CL (30 sec, 0.53% of injected dose) than in the femoral vein (150 sec, 0.08% of injected dose). Removal of the ovary +CL was followed by a brief maintenance of peripheral progesterone within luteal-phase levels. The in-vitro progesterone production by a suspension of cells isolated from the corpus luteum was 47.5 +/- 12.8 ng/ml/2 h, whereas luteal-like cells isolated from the ovary -CL secreted 14.3 +/- 6.0 ng/ml/2 h (P less than 0.01) into the medium. We therefore suggest that the symmetrical and high secretion rate of progesterone by the ovaries of the capuchin monkey indicates a between-ovary communication system, and that the luteal-like tissue of the ovary -CL can produce relatively large amounts of progesterone.

Model‐based meta‐analysis of salbutamol pharmacokinetics and practical implications for doping control

Salbutamol was included in the prohibited list of the World Anti‐Doping Agency (WADA) in 2004. Although systemic intake is banned, inhalation for asthma is permitted but with dosage restrictions. The WADA established a urinary concentration threshold to distinguish accordingly prohibited systemic self‐administration from therapeutic prescription by inhalation. This study aimed at evaluating the ability of the WADA threshold to differentiate salbutamol therapeutic use from violation of antidoping rules. Concentration‐time profile of salbutamol in plasma and its excretion in urine was characterized through a model‐based meta‐analysis of individual and aggregate data collected after administration of a large range of doses following different modes of administration and under a variety of conditions. The developed model adequately fitted salbutamol plasma and urine concentration‐time profiles of the 13 selected studies. Model‐based simulations confirmed that a wide range of salbutamol urine concentrations might be measured after drug intake. Although violation of the WADA Code can be strongly suspected in individuals showing very high salbutamol urine concentrations, uncertainty remains for values close to the WADA threshold as they can be compatible with both permitted therapeutic use and violation. Although not entirely discriminant, the current WADA rule is globally supported by our appraisal. It could be further improved by a slight and reasonable adjustment of inhaled daily dosages allowed for therapeutic use. Our model might help antidoping experts in the evaluation of suspected doping cases through confronting the athlete's urine measurements with their allegations about salbutamol treatment.