RESUMEN
Anxiety disorders affect approximately 20% of the population, and women are twice as likely as men to develop anxiety disorders. Despite these findings, little is known about the effects of gender on tolerability and therapeutic efficacy of anxiolytic drugs. Sex differences are also observed in rodents, even though the majority of preclinical behavioral studies are conducted on males. The aim of this study was to investigate sex differences in anxiety-like behavior using the Vogel conflict test and the pharmacological responsiveness to a variety of psychoactive drugs in rats. Pharmacological treatments clinically used for the treatment of anxiety were tested in male and female rats. Overall, female rats accepted fewer punished responses, had lower levels of water intake even when matched for weight, and had a lower pain threshold for electrical footshock than males. Diazepam and chlordiazepoxide displayed anxiolytic-like effects in both genders. In contrast, buspirone, propranolol, fluoxetine and paroxetine showed activity only in male rats. Morphine had no anxiolytic-like activity in either gender. Analysis of the estrous cycle did not reveal any effect of cycle stage on behavioral or drug responses. This investigation highlights the importance of using female subjects in the preclinical research of anxiety and the screening of anxiolytic compounds in the drug development process.
Asunto(s)
Ansiolíticos/uso terapéutico , Ansiedad/tratamiento farmacológico , Conducta Animal/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Caracteres Sexuales , Análisis de Varianza , Animales , Ansiedad/fisiopatología , Ciclo Estral/fisiología , Femenino , Masculino , Ratas , Ratas WistarRESUMEN
RATIONALE: Neuroleptic dysphoria encompasses a range of unpleasant subjective responses and, as a result, is difficult to study in preclinical animal models. OBJECTIVE: Based on the learned helplessness model of depression, increases in escape failures (EFs) in the drug-induced helplessness test (DH) are proposed to reflect drug-induced depressive-like state, a contributing factor to neuroleptic dysphoria in humans. MATERIALS AND METHODS: Effects of the typical antipsychotic haloperidol and the atypical antipsychotics risperidone, olanzapine, aripiprazole, quetiapine, and clozapine were investigated in the DH test. We further characterized this test by examining compounds affecting motor function, cognition, anxiety, and those with antidepressant activity. RESULTS: The antipsychotics haloperidol, risperidone, aripiprazole, and olanzapine, all increased EFs, while quetiapine had no effect, and clozapine reduced EFs. Amphetamine, diazepam, and ciproxifan, had no effect on EFs. Scopolamine significantly reduced EFs and MK-801 showed a trend toward reducing EFs at doses not significantly sti mulating locomotor activity. Subchronic, but not acute, imipramine and subchronic fluoxetine significantly reduced EFs at doses significantly suppressing locomotor activity. Dissociation appears to exist between performance in the DH test and compound effects on catalepsy or locomotor activity. CONCLUSIONS: After discussing potential alternative interpretations of the drug-induced changes of EFs, we propose the DH test as a useful test for assessing a drug-induced, depressive-like state that may contribute to neuroleptic dysphoria.
Asunto(s)
Afecto/efectos de los fármacos , Antidepresivos/farmacología , Antipsicóticos/toxicidad , Modelos Animales de Enfermedad , Reacción de Fuga/efectos de los fármacos , Desamparo Adquirido , Motivación , Animales , Antipsicóticos/antagonistas & inhibidores , Nivel de Alerta/efectos de los fármacos , Reacción de Prevención/efectos de los fármacos , Concienciación/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Actividad Motora/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Tiempo de Reacción/efectos de los fármacosRESUMEN
The aim of this study was to validate melanin-concentrating hormone (MCH)-1 receptor antagonism as a potential treatment of mood disorders. We attempted to replicate the effects previously reported with SNAP-7941 and expanded the investigation to three other orally bioavailable MCH-1 receptor antagonists with good brain penetration. SNAP-7941 (3-30 mg/kg, i.p.) and T-226296 (5-60 mg/kg, p.o.) (+/- racemate), were evaluated in the rat forced swim and mouse tail suspension tests. (+)SNAP-7941 (3-10 mg/kg, p.o.) was also tested in a modified 5-min rat forced swim protocol as previously reported. A-665798 (3-30 mg/kg, p.o.) and A-777903 (3-30 mg/kg, p.o.) were tested in mouse tail suspension and rat Vogel tests. None of the compounds showed meaningful efficacy in the paradigms tested. The lack of efficacy with four structurally different MCH-1 receptor antagonists does not support a role for therapeutic treatment of depression/anxiety via this mechanism of action.
Asunto(s)
Ansiedad/prevención & control , Compuestos de Bifenilo/farmacología , Trastorno Depresivo/prevención & control , Naftalenos/farmacología , Piperidinas/farmacología , Pirimidinas/farmacología , Receptores de Somatostatina/antagonistas & inhibidores , Análisis de Varianza , Animales , Ansiedad/fisiopatología , Benzopiranos/farmacología , Conflicto Psicológico , Trastorno Depresivo/fisiopatología , Modelos Animales de Enfermedad , Suspensión Trasera/fisiología , Indazoles/farmacología , Masculino , Ratones , Ratones Endogámicos BALB C , Actividad Motora/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Receptores de Somatostatina/fisiología , NataciónRESUMEN
Dopamine plays a role in the pathophysiology of depression and therapeutic effects of antidepressants but the contribution of individual D(2)-like receptor subtypes (D(2), D(3), D(4)) to depression is not known. We present evidence that activation of D(2)/D(3), but not D(4) receptors, can affect the outcome in the rat forced swim test (FST). Nomifensine, a dopamine uptake inhibitor (7, 14, and 28 micromol/kg); quinpirole, a D(2)-like receptor and agonist (0.4, 1.0, and 2.0 micromol/kg); PD 12,8907, a preferential D(3) receptor agonist (0.17, 0.35, and 0.7 micromol/kg); PD 168077 (0.1, 0.3, and 1.0 micromol/kg) and CP 226269 (0.3, 1.0, and 3.0 micromol/kg), both selective D(4) receptor agonists, were administered s.c. 24, 5, and 0.5/1 h before testing. Nomifensine, quinpirole at all doses and PD 128907 at the highest dose decreased immobility time in FST. PD 168077 and CP 226269 had no effect on the model. To further clarify what type of dopamine receptors were involved in the anti-immobility effect of quinpirole, we tested different antagonists. Haloperidol, a D(2)-like receptor antagonist (0.27 micromol/kg), completely blocked the effect of quinpirole; A-437203 (LU-201640), a selective D(3) receptor antagonist (17.46 micromol/kg), showed a nonsignificant trend to attenuate the effect of the low dose of quinpirole, and L-745,870, a selective D(4) receptor antagonist (1.15 micromol/kg), had no effect. The pharmacological selectivity of the compounds tested suggests that the antidepressant-like effects of quinpirole are most likely mediated mainly by D(2) and to a lesser extent by D(3) but not D(4) receptors.
Asunto(s)
Antidepresivos/uso terapéutico , Depresión/tratamiento farmacológico , Receptores de Dopamina D2/fisiología , Natación , Análisis de Varianza , Animales , Conducta Animal/efectos de los fármacos , Depresión/metabolismo , Modelos Animales de Enfermedad , Agonistas de Dopamina/farmacología , Antagonistas de Dopamina/farmacología , Inhibidores de Captación de Dopamina/farmacología , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Masculino , Actividad Motora/efectos de los fármacos , Nomifensina/farmacología , Ratas , Receptores de Dopamina D3 , Factores de TiempoRESUMEN
RATIONALE: The rat neonatal ventral hippocampal (VH) ibotenic lesion model has been proposed as a developmental model of schizophrenia, based on evidence that it encompasses aspects of the disorder including psychomotor agitation (hyperactivity), deficits in prepulse inhibition (PPI), and deficits in social interaction (SI), measures presumed to reflect positive symptoms, sensory gating deficits and negative symptoms, respectively. However, validation of the model as a predictive pharmacological screening tool has been minimal. OBJECTIVE: Determine the effects of a chronic 3-week low dose treatment of clozapine or risperidone on locomotor hyperactivity, PPI and SI in lesioned and control rats. RESULTS: Both clozapine, 2.5 mg/kg per day IP and risperidone, 0.1 mg/kg per day IP, reversed lesion-induced locomotor hyperactivity; however, the compounds also decreased locomotor activity in the non-lesioned controls. Clozapine 2.5 mg/kg per day and risperidone 0.1 mg/kg per day significantly attenuated lesion-induced PPI deficits. Neither compound induced a significant attenuation of lesion-induced SI deficits. In order to see if SI deficits required a higher dose of an antipsychotic, the dose of clozapine was increased to 4 mg/kg per day; however this dose induced such marked decreases in the activity and startle responses in the control rats, i.e. up to 74% decrease, that the effects on the lesioned rats could not be adequately interpreted. CONCLUSIONS: These data add further support to the neonatal VH lesion model as a predictive pharmacological screening assay for identifying compounds effective in the treatment of positive symptoms of schizophrenia. However, the usefulness of the model in detecting compounds effective in treating negative symptoms of schizophrenia is still in question.