Papers by Jose Jimenez Mena
Changes induced by ovariectomy on the acute effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in a model of rat poor metabolizer of debrisoquine
Parkinsonism & Related Disorders, 1996
The female 'dark-adapted&... more The female 'dark-adapted' rat, an animal model of poor metabolizer of debrisoquine, is more susceptible to neurotoxic effects of 1,2,3,6-tetrahydropyridine (MPTP) than other rat species (extensive metabolizers). Since ovariectomy improves the ability for the 4-hydroxylation of debrisoquine in female 'dark-adapted' rats, we studied the acute effects of MPTP (three doses of 10, 20, and 30 mg/kg s.c., respectively, at 12 hour intervals) in ovariectomized and laparotomized female 'dark-adapted' rats to test whether ovariectomy prevents MPTP-induced neurotoxicity. We measured regional brain monoamine levels. MPTP-induced depletion of dopamine (DA) and its metabolites was more prominent in the striatum. Ovariectomy, by itself, reduced dopamine and serotonin (5-HT) and their metabolites in striatum in both control and MPTP-treated animals. Factorial analysis of the effects of ovariectomy and MPTP treatment by two-way ANOVA revealed that both experimental procedures reduced DA and 5-HT neurotransmission in the striatum while the combined effect of both treatments did not produce any significant change. In spite of its induction of monoamine depletion in intact animals, ovariectomy partially prevented MPTP-induced depletion of monoamines in the surviving rats, suggesting that changes in metabolic rates of debrisoquine induced by ovariectomy produce resistance to MPTP in 'dark-adapted' rats.
Acta Psychiatrica Scandinavica, 2008
Objective: P50 gating in schizophrenia has contributed much to our understanding of the pathophy... more Objective: P50 gating in schizophrenia has contributed much to our understanding of the pathophysiology of the illness. We examined euthymic bipolar patients to determine if they also have a P50 gating deficit.Method: P50 gating was measured in 81 euthymic bipolar patients (50 with a lifetime history of psychotic symptoms), 92 stable schizophrenic patients, and 67 control subjects.Results: P50 gating was significantly lower in control subjects than in bipolar patients with a lifetime history of psychosis (P = 0.001) and schizophrenic patients (P = 0.0001). In all patient groups, the percentage of patients with P50 gating was higher than in the control group (χ2 = 30.596; P < 0.0001). There was no statistically significant correlation between P50 gating and other clinical variables.Conclusion: Our data suggest that P50 gating deficit is a neurobiological marker that is present in stable schizophrenic patients and euthymic bipolar patients.
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Papers by Jose Jimenez Mena