Pharmacological interaction of Galphimia glauca extract and natural galphimines with Ketamine and Haloperidol on different behavioral tests.

Due to the high prevalence of psychiatric disorders and the prevalent side effects produced by the antipsychotic drugs available, it is necessary to search for new therapeutic options. Galphimia glauca has been used for many years in Mexican traditional medicine for treating mental diseases. From this plant, some compounds, denominated galphimines, have been discovered and have shown to possess the ability of modifying the frequency of discharge of dopaminergic neurons in the Ventral tegmental area. The objective of the present work was to evaluate the effect produced by the G. glauca extract, a Galphimine rich fraction (GRF), as well as the pure galphimines (G-A, G-B, and G-E) on behavioral models in mice. Products obtained from G. glauca were evaluated in the Haloperidol-induced catalepsy test and in the acute schizophrenia-like symptoms-induced with Ketamine (KET) in mice. Catalepsy was evaluated through the bar test, and schizophrenia-like symptoms, by means of the Open Field Test (OFT), Passive Avoidance Test (PAT), and the Forced Swimming Test (FST). The methanolic extract from G. glauca, GRF, and the pure galphimines were able to interact with the dopaminergic pathway and modify the behavioral response such as to potentiate the cataleptic effect induced with Haloperidol and to inhibit the behavior induced by KET in mice exposed to OFT, and FST. Moreover, the G. glauca extract and GRF were capable of blocking the cognitive decline that was induced with KET in mice (evaluated by PAT). Based on these results, it is possible to assume that part of the effect of G. glauca is due to the interaction of Galphimines with the dopaminergic and glutamatergic systems in vivo. It can be concluded that the products obtained from G. glauca potentiate the cataleptic effect induced with Haloperidol and show a protector effect on some of the symptoms generated by KET in mice (KET is capable of provoking halucinations in humans and psychosis-like behaviour in mice). With this basis, the metanolic extract from G. glauca, and the GRF are capable of blocking positive and cognitive symptoms associated with psychosis induced by KET. In addition, it could be suggested that the galphimines are responsible for the inhibition of the positive symptoms observed.