Browsing by Author "Pontes, Helena"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Ethanol, the forgotten artifact in cell culturePublication . Pontes, Helena; Carvalho, Márcia; Guedes de Pinho, Paula; Carmo, Helena; Remião, Fernando; Carvalho, Félix; Bastos, Maria de Lourdes
- Mechanisms underlying the hepatotoxic effects of ecstasyPublication . Carvalho, Márcia; Pontes, Helena; Remiao, Fernando; Bastos, Maria L.; Carvalho, Felix3,4-Methylenedioxymethamphetamine (MDMA or ecstasy) is a worldwide illegally used amphetamine-derived designer drug known to be hepatotoxic to humans. Jaundice, hepatomegaly, centrilobular necrosis, hepatitis and fibrosis represent some of the adverse effects caused by MDMA in the liver. Although there is irrefutable evidence of MDMA-induced hepatocellular damage, the mechanisms responsible for that toxicity remain to be thoroughly clarified. One well thought-of mechanism imply MDMA metabolism in the liver into reactive metabolites as responsible for the MDMA-elicited hepatotoxicity. However, other factors, including MDMA-induced hyperthermia, the increase in neurotransmitters efflux, the oxidation of biogenic amines, polydrug abuse pattern, and environmental features accompanying illicit MDMA use, may increase the risk for liver complications. Liver damage patterns of MDMA in animals and humans and current research on the mechanisms underlying the hepatotoxic effects of MDMA will be highlighted in this review.
- Toxicity of amphetamines: an updatePublication . Carvalho, Márcia; Carmo, Helena; Costa, Vera Marisa; Capela, João Paulo; Pontes, Helena; Remião, Fernando; Carvalho, Félix; Bastos, Maria de LourdesAmphetamines represent a class of psychotropic compounds, widely abused for their stimulant, euphoric, anorectic, and, in some cases, emphathogenic, entactogenic, and hallucinogenic properties. These compounds derive from the β-phenylethylamine core structure and are kinetically and dynamically characterized by easily crossing the blood-brain barrier, to resist brain biotransformation and to release monoamine neurotransmitters from nerve endings. Although amphetamines are widely acknowledged as synthetic drugs, of which amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are well-known examples, humans have used natural amphetamines for several millenniums, through the consumption of amphetamines produced in plants, namely cathinone (khat), obtained from the plant Catha edulis and ephedrine, obtained from various plants in the genus Ephedra. More recently, a wave of new amphetamines has emerged in the market, mainly constituted of cathinone derivatives, including mephedrone, methylone, methedrone, and buthylone, among others. Although intoxications by amphetamines continue to be common causes of emergency department and hospital admissions, it is frequent to find the sophism that amphetamine derivatives, namely those appearing more recently, are relatively safe. However, human intoxications by these drugs are increasingly being reported, with similar patterns compared to those previously seen with classical amphetamines. That is not surprising, considering the similar structures and mechanisms of action among the different amphetamines, conferring similar toxicokinetic and toxicological profiles to these compounds. The aim of the present review is to give an insight into the pharmacokinetics, general mechanisms of biological and toxicological actions, and the main target organs for the toxicity of amphetamines. Although there is still scarce knowledge from novel amphetamines to draw mechanistic insights, the long-studied classical amphetamines-amphetamine itself, as well as methamphetamine and MDMA, provide plenty of data that may be useful to predict toxicological outcome to improvident abusers and are for that reason the main focus of this review.