Reversal and Preventive Pleiotropic Mechanisms Involved in the Antipsychotic-Like Effect of Taurine, an Essential ß-Amino Acid in Ketamine-Induced Experimental Schizophrenia in Mice.

Schizophrenia is a life disabling, multisystem neuropsychiatric disease mostly derived from complex epigenetic-mediated neurobiological changes causing behavioural deficits. Neurochemical disorganizations, neurotrophic and neuroimmune alterations are some of the challenging neuropathologies proving unabated during psychopharmacology of schizophrenia, further bedeviled by drug-induced metabolic derangements including alteration of amino acids. In first-episode schizophrenia patients, taurine, an essential ß-amino acid represses psychotic-symptoms. However, its anti-psychotic-like mechanisms remain incomplete. This study evaluated the ability of taurine to prevent or reverse ketamine-induced experimental psychosis and the underlying neurochemical, neurotrophic and neuroinmune mechanisms involved in taurine's clinical action. The study consisted of three different experiments with Swiss mice (n = 7). In the drug alone, mice received saline (10 mL/kg/p.o./day), taurine (50 and 100 mg/kg/p.o./day) and risperidone (0.5 mg/kg/p.o./day) for 14 days. In the preventive study of separate cohort, mice were concomitantly given ketamine (20 mg/kg/i.p./day) from days 8 to 14. In the reversal study, mice received ketamine for 14 days before taurine or risperidone treatments from days 8 to 14 respectively. Afterwards, stereotypy behaviour, social, non-spatial memory deficits, and body weights were assessed. Neurochemical (dopamine, 5-hydroxytryptamine, glutamic acid decarboxylase, (GAD)), brain derived-neurotrophic factor (BDNF) and pro-inflammatory cytokines [tumor necrosis factor-alpha, (TNF-α), interleukin-6, (IL-6)] were assayed in the striatum, prefrontal-cortex and hippocampal area. Taurine attenuates ketamine-induced schizophrenia-like behaviour without changes in body weight. Taurine reduced ketamine-induced dopamine and 5-hydroxytryptamine changes, and increased GAD and BDNF levels in the striatum, prefrontal-cortex and hippocampus, suggesting increased GABAergic and neurotrophic transmissions. Taurine decreases ketamine-induced increased in TNF-α and IL-6 concentrations in the striatum, prefrontal-cortex and hippocampus. These findings also suggest that taurine protects against schizophrenia through neurochemical modulations, neurotrophic enhancement, and inhibition of neuropathologic cytokine activities.

Antidiarrheal and antimicrobial activities of the ethanol extract from the Icacina senegalensis root bark.

BACKGROUND: The Icacina senegalensis root bark is traditionally used for the treatment of gastrointestinal disorders in Nigeria. To date, no scientific study has substantiated or refuted this claim. METHODS: The antidiarrheal and antimicrobial activities of the ethanol root bark extract were investigated in rats and against some selected diarrhea-causing microorganisms. RESULTS: The extract significantly decreased the frequency of castor oil-induced diarrhea, and inhibited the masses and volumes of intestinal fluid accumulation in the castor oil-induced enteropooling method. The distance travelled by the charcoal meal was also decreased by the extract gastrointestinal transit method. The extract also strongly inhibited the growth of some selected microorganisms. CONCLUSIONS: The ethanol extract of the I. senegalensis root bark showed antidiarrheal activity, thus justifying its long folkloric use in diarrhea treatment. The extract also demonstrated antimicrobial activity against selected diarrheal causing organisms.

Antiplasmodial activity of the ethanolic root bark extract of Icacina senegalensis in mice infected by Plasmodium berghei.

BACKGROUND: The root of Icacina senegalensis is used for the treatment of malaria and related conditions in southeastern Nigeria. METHODS: To establish its efficacy, the ethanolic root bark extract was investigated as antiplasmodial agent against Plasmodium berghei in mice. A 4-day suppressive test and the curative effect against established infection models of antiplasmodial studies were used. RESULTS: The root bark extract of I. senegalensis (50, 100, and 200 mg/kg) exhibited a significant (p<0.05) dose-dependent activity against the parasite based on suppressive and curative study. The antimalarial effect of I. senegalensis is compared with that of chloroquine (10 mg/kg), the standard drug. The ethanolic root bark extract also prolonged the survival time of infected mice. CONCLUSIONS: The results showed that the root bark extract possesses a potential antiplasmodial activity, which can be exploited for the possible development of new antimalarial agent.