RESUMEN
Previous findings indicate that post-training administration of glucocorticoid stress hormones can interact with the noradrenergic system to enhance consolidation of hippocampus- or amygdala-dependent cognitive/emotional memory. The present experiments were designed to extend these findings by examining the potential interaction of glucocorticoid and noradrenergic mechanisms in enhancement of dorsolateral striatum (DLS)-dependent habit memory. In experiment 1, different groups of adult male Long-Evans rats received training in two DLS-dependent memory tasks. In a cued water maze task, rats were released from various start points and were reinforced to approach a visibly cued escape platform. In a response-learning version of the water plus-maze task, animals were released from opposite starting positions and were reinforced to make a consistent egocentric body-turn to reach a hidden escape platform. Immediately post-training, rats received peripheral injections of the glucocorticoid corticosterone (1 or 3 mg/kg) or vehicle solution. In both tasks, corticosterone (3 mg/kg) enhanced DLS-dependent habit memory. In experiment 2, a separate group of animals received training in the response learning version of the water plus-maze task and were given peripheral post-training injections of corticosterone (3 mg/kg), the ß-adrenoreceptor antagonist propranolol (3 mg/kg), corticosterone and propranolol concurrently, or control vehicle solution. Corticosterone injections again enhanced DLS-dependent memory, and this effect was blocked by concurrent administration of propranolol. Propranolol administration by itself (3 mg/kg) did not influence DLS-dependent memory. Taken together, the findings indicate an interaction between glucocorticoid and noradrenergic mechanisms in DLS-dependent habit memory. Propranolol administration may be useful in treating stress-related human psychopathologies associated with a dysfunctional DLS-dependent habit memory system.
Asunto(s)
Cuerpo Estriado/metabolismo , Corticosterona/metabolismo , Glucocorticoides/metabolismo , Hábitos , Memoria/fisiología , Receptores Adrenérgicos beta/metabolismo , Antagonistas Adrenérgicos beta/farmacología , Animales , Cuerpo Estriado/efectos de los fármacos , Corticosterona/administración & dosificación , Señales (Psicología) , Relación Dosis-Respuesta a Droga , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Memoria/efectos de los fármacos , Propranolol/farmacología , Ratas Long-Evans , Refuerzo en PsicologíaRESUMEN
BACKGROUND: The majority of primary care consultations in Malaysia occur in the general practice clinics. To date, there is no comprehensive documentation of the morbidity and practice activities in this setting. OBJECTIVES: We reported the reasons for encounter, diagnoses and process of care in urban general practice and the influence of payment system on the morbidity and practice activities. METHODS: 115 clinics in Kuala Lumpur, Ipoh and Penang participated in this study. General practitioners in these clinics completed a 2-page questionnaire for each of the 30 consecutive patients. The questionnaire requested for the following information: demographic data, reasons for encounter, important physical findings, diagnoses, investigations ordered, outpatient procedures performed, medical certificate given, medication prescribed and referral made. The morbidity (reasons for encounter and diagnoses) was coded using ICPC-2 and the medication data was coded using MIMS Classification Index. RESULTS: During 3481 encounters, 5300 RFEs (152 RFEs per 100 encounters) and 3342 diagnoses (96 diagnoses per 100 encounters) were recorded. The majority of the RFEs and diagnoses are in the following ICPC Chapters: Respiratory, General and unspecified, Digestive, Neurological, Musculoskeletal and Skin. The frequencies of selected aspects of the process of care (rate per 100 encounters) were: laboratory investigations 14.7, outpatient procedures 2.4, sick certification 26.9, referral 2.4, and medication prescription 244. Consultation for chronic diseases and acute infections were influenced more by demographic variables (age, employment) rather than payment system. Cash-paying patients were more likely to receive laboratory investigations and injections. CONCLUSION: This study demonstrated the breadth of clinical care in the general practice. Relatively fewer patients consulted specifically for preventive care and treatment of chronic diseases. The frequencies of outpatient procedures and referrals appeared to be low. Payment system results in important differences in patient mix and influences some types of practice activities.