Gender and estrous cycle influences on behavioral and neurochemical alterations in adult rats neonatally administered ketamine

Neonatal N-methyl-D-aspartate (NMDA) receptor blockade in rodents triggers schizophrenia (SCZ)-like alterations during adult life. SCZ is influenced by gender in age of onset, premorbid functioning, and course. Estrogen, the hormone potentially driving the gender differences in SCZ, is known to present neuroprotective effects such as regulate oxidative pathways and the expression of brain-derived neurotrophic factor (BDNF). Thus, the aim of this study was to verify if differences in gender and/or estrous cycle phase during adulthood would influence the development of behavioral and neurochemical alterations in animals neonatally administered ketamine. The results showed that ketamine-treated male (KT-male) and female-in-diestrus (KTF-diestrus, the low estrogen phase) presented significant deficits in prepulse inhibition of the startle reflex and spatial working memory, two behavioral SCZ endophenotypes. On the contrary, female ketamine-treated rats during proestrus (KTF-proestrus, the high estradiol phase) had no behavioral alterations. This correlated with an oxidative imbalance in the hippocampus (HC) of both male and KTF-diestrus female rats, that is, decreased levels of GSH and increased levels of lipid peroxidation and nitrite. Similarly, BDNF was decreased in the KTF-diestrus rats while no alterations were observed in KTF-proestrus and male animals. The changes in the HC were in contrast to those in the prefrontal cortex in which only increased levels of nitrite in all groups studied were observed. Thus, there is a gender difference in the adult rat HC in response to ketamine neonatal administration, which is based on the estrous cycle. This is discussed in relation to neuropsychiatric conditions and in particular SCZ.

Prevention and reversal of ketamine-induced schizophrenia related behavior by minocycline in mice: Possible involvement of antioxidant and nitrergic pathways

It has been hypothesized that oxidative imbalance and alterations in nitrergic signaling play a role in the neurobiology of schizophrenia. Preliminary evidence suggests that adjunctive minocycline treatment is efficacious for cognitive and negative symptoms of schizophrenia. This study investigated the effects of minocycline in the prevention and reversal of ketamine-induced schizophrenia-like behaviors in mice. In the reversal protocol, animals received ketamine (20 mg/kg per day intraperitoneally or saline for 14 days, and minocycline (25 or 50 mg/kg daily), risperidone or vehicle treatment from days 8 to 14. In the prevention protocol, mice were pretreated with minocycline, risperidone or vehicle prior to ketamine. Behaviors related to positive (locomotor activity and prepulse inhibition of startle), negative (social interaction) and cognitive (Y maze) symptoms of schizophrenia were also assessed. Glutathione (GSH), thiobarbituric acid-reactive substances (TBARS) and nitrite levels were measured in the prefrontal cortex, hippocampus and striatum. Minocycline and risperidone prevented and reversed ketamine-induced alterations in behavioral paradigms, oxidative markers (i.e. ketamine-induced decrease and increase in GSH levels and TBARS content, respectively) as well as nitrite levels in the striatum. These data provide a rationale for evaluating minocycline as a novel psychotropic agent and suggest that its mechanism of action includes antioxidant and nitrergic systems.

Neuropsychiatric Symptoms (NPS) in patients with pure Vascular Dementia (VaD) and Mixed Dementia (MD) from a memory outpatient clinic in southeast Brazil

Vascular Dementia (VaD) and Vascular Cognitive Impairment (VCI) are increasingly common worldwide. Nevertheless, the clinical-neuropsychiatric profile of these patients at presentation is still poorly characterized in developing countries.

OBJECTIVE

We aimed to characterize the prevalence of neuropsychiatric symptoms, as well as the clinical and cognitive profile of patients with VaD and VCI in our tertiary University outpatient cognitive clinic.

METHODS

We reviewed data on 253 patients diagnosed with VaD or VCI at our center between January 1996 and December 2005, located in an industrial region of the state of Sao Paulo, southeast Brazil. We excluded 19 patients who did not complete the medical investigation or who did not meet the clinical or neuroimaging criteria for vascular dementia. We collected socio-demographic data, educational level, vascular risk factors, behavioral and neuropsychological symptoms and cognitive complaints at presentation.

RESULTS

Two hundred and thirty-four cases were included in this analysis. The mean age was 67.77±10.35 years; 72% were males and 82% had less than four years of education (average 2.84±2.96 years). The initial Clinical Dementia Rating score was 2 & 3 in 68%. A total of 185 patients had neuropsychiatric symptoms distributed in main categories as follows: psychosis (52.6%), hallucinations (23.5%), psychomotor agitation (22.5%), depression (17.5%) and apathy (17.5%). Hypertension and previous stroke were the most prevalent risk factors.

CONCLUSION

We found a high prevalence of neuropsychiatric symptoms. The clinical-neuropsychiatric profile of patients presenting to cognitive clinics in developing countries may differ greatly to that of more developed nations. These characteristics may have implications for public health strategies.