RESUMO
Neonatal handling has an impact on adult behavior of experimental animals and is associated with rapid and increased palatable food ingestion, impaired behavioral flexibility, and fearless behavior to novel environments. These symptoms are characteristic features of impulsive trait, being controlled by the medial prefrontal cortex (mPFC). Impulsive behavior is a key component of many psychiatric disorders such as attention deficit hyperactivity disorder (ADHD), manic behavior, and schizophrenia. Others have reported a methylphenidate (MPH)-induced enhancement of mPFC functioning and improvements in behavioral core symptoms of ADHD patients. The aims of the present study were: (i) to find in vivo evidence for an association between neonatal handling and the development of impulsive behavior in adult Wistar rats and (ii) to test whether neonatal handling could have an impact on monoamine levels in the mPFC and the pharmacological response to MPH in vivo. Therefore, experimental animals (litters) were classified as: "non-handled" and "handled" (10[Formula: see text]min/day, postnatal days 1-10). After puberty, they were exposed to either a larger and delayed or smaller and immediate reward (tolerance to delay of reward task). Acute MPH (3[Formula: see text]mg/Kg. i.p.) was used to suppress and/or regulate impulsive behavior. Our results show that only neonatally handled male adult Wistar rats exhibit impulsive behavior with no significant differences in monoamine levels in the medial prefrontal cortex, together with a decreased response to MPH. On this basis, we postulate that early life interventions may have long-term effects on inhibitory control mechanisms and affect the later response to pharmacological agents during adulthood.
Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Manobra Psicológica , Comportamento Impulsivo/efeitos dos fármacos , Comportamento Impulsivo/fisiologia , Metilfenidato/farmacologia , Fatores Etários , Análise de Variância , Animais , Animais Recém-Nascidos , Monoaminas Biogênicas/metabolismo , Peso Corporal/efeitos dos fármacos , Condicionamento Operante , Modelos Animais de Doenças , Feminino , Masculino , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Gravidez , Ratos , Ratos Wistar , Reforço Psicológico , Fatores Sexuais , Fatores de TempoRESUMO
Parkinson's disease (PD) is characterized by the manifestation of akinesia, slowness to initiate movement, muscle rigidity, and tremors. However, recent evidence indicates that this pathology also causes alterations in proprioception. Disturbances in proprioceptive mechanisms directly affect postural control and the ability to calculate the velocity and amplitude of movement, suggesting that these alterations are related to the motor symptoms of PD. This article reviews the clinical data on these symptoms and presents evidence of a connection between proprioceptive deficits and the physiology of PD. The identification of proprioceptive impairments in different forms of Parkinsonism can provide valuable clues on the physiopathology of proprioception in idiopathic PD.
Assuntos
Modelos Animais , Doença de Parkinson , PropriocepçãoRESUMO
Parkinson's disease (PD) is characterized by the manifestation of akinesia, slowness to initiate movement, muscle rigidity, and tremors. However, recent evidence indicates that this pathology also causes alterations in proprioception. Disturbances in proprioceptive mechanisms directly affect postural control and the ability to calculate the velocity and amplitude of movement, suggesting that these alterations are related to the motor symptoms of PD. This article reviews the clinical data on these symptoms and presents evidence of a connection between proprioceptive deficits and the physiology of PD. The identification of proprioceptive impairments in different forms of Parkinsonism can provide valuable clues on the physiopathology of proprioception in idiopathic PD.(AU)