Animal models for predicting the efficacy and side effects of antipsychotic drugs

The use of antipsychotic drugs represents an important approach for the treatment of schizophrenia. However, their efficacy is limited to certain symptoms of this disorder, and they induce serious side effects. As a result, there is a strong demand for the development of new drugs, which depends on reliable animal models for pharmacological characterization. The present review discusses the face, construct, and predictive validity of classical animal models for studying the efficacy and side effects of compounds for the treatment of schizophrenia. These models are based on the properties of antipsychotics to impair the conditioned avoidance response and reverse certain behavioral changes induced by psychotomimetic drugs, such as stereotypies, hyperlocomotion, and deficit in prepulse inhibition of the startle response. Other tests, which are not specific to schizophrenia, may predict drug effects on negative and cognitive symptoms, such as deficits in social interaction and memory impairment. Regarding motor side effects, the catalepsy test predicts the liability of a drug to induce Parkinson-like syndrome, whereas vacuous chewing movements predict the liability to induce dyskinesia after chronic treatment. Despite certain limitations, these models may contribute to the development of more safe and efficacious antipsychotic drugs.

Developing new medicines from cannabis sativa: challenges and perspectives / Desenvolvendo medicamentos a partir da cannabis sativa: desafios e perspectivas

Objetivo. Elaborar uma revisão crítica a respeito das aplicações medicinais da Cannabis sativa e de compostos a ela relacionados.Método. O texto foi baseado nos principais artigos relatando as descobertas dos mecanismos pelos quais a maconha exerce seus efeitos, bem como em pesquisas atuais que tentam desenvolver novos medicamentos com base no sistema endocanabinoide.Resultados. Embora a Cannabis sativa venha sendo utilizada há séculos, há poucas aplicações para essa planta na medicina atual. Porém, o progresso significante nessa área, com a caracterização do sistema endocanabinoide no cérebro, sugere a possibilidade de se desenvolverem novos medicamentos para o tratamento de doenças do sistemanervoso central, tais como transtornos de ansiedade e do humor e epilepsia. Conclusão. A pesquisa sobre as propriedades farmacológicas e terapêuticas da Cannabis sativa e de compostos relacionados representa uma estratégia promissora para o desenvolvimento de drogas. No entanto, esta perspective requer cautela, considerando-se alguns efeitos potencialmente deletérios, bem como as controvérsias que podem serobservadas dos pontos de vista social e político.

Objective. The aim of this paper is to critically review the medical applications of Cannabis sativa and related compounds.Method. The text is based on the main articles on the discovery of the mechanisms through which cannabis exerts its effects, as well as on contemporary research trying to develop new medicines based on the endocannabinoid system. Results. Despite the ancient use of Cannabis sativa, there have been very few applications of thus herb incontemporary medicine. Nonetheless, the significant progress in this , with the characterization of the endocannabinoid system in the brain, points to the possibility of developing new medicaments for the treatment of disorders of the central nervous system, such as anxiety, mood disorders and epilepsy. Conclusion. The research on the pharmacological and therapeutic properties of Cannabis sativa and relatedcompounds is a promising approach for drug development. However, this perspective must be tempered considering some potentially deleterious effects as well as the controversies that can be seen from social and political standpoints.