Efeitos comportamentais e neuroquímicos agudos da cafeína em ratos adolescentes e adultos
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Data
2010-08-20
Autores
Possi, Ana Paula Marques [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A cafeína é provavelmente a substância psicoativa mais consumida no mundo. Essa substância está presente em alimentos, bebidas e medicamentos, sendo esses comercializados para indivíduos de todas as idades. Apesar disto, os efeitos da cafeína sobre os adolescentes são pouco compreendidos. Assim, o objetivo do presente estudo foi investigar os efeitos psicomotores e neuroquímicos da cafeína em ratos adolescentes e adultos. Para tanto, ratos Wistar adolescentes (dia pós-natal 37 - 40) ou adultos (dia pós-natal 70 - 74) tiveram sua atividade locomotora registrada após injeção intraperitoneal (i.p.) de salina ou cafeína (3, 10, 30, 60 ou 120 mg/kg). Em outro experimento ratos adolescentes e adultos receberam injeção i.p. de salina ou cafeína nas doses de 30 ou 100 mg/kg e as concentrações de dopamina, serotonina e seus metabólitos foram determinadas no córtex pré-frontal medial (CPFm), núcleo acumbens (NAc), caudado putamem (CPu) e área tegmental ventral (ATV) por cromatrografia líquida de alta resolução acoplada a detector eletroquímico. Nossos resultados demonstraram que a cafeína nas doses de 10 e 30 mg/kg induziram estimulação da atividade locomotora em ambos as idades, enquanto as doses mais elevadas (60 e 120 mg/kg) somente estimulou a atividade locomotora nos animais adolescentes. A injeção aguda de cafeína na dose de 30 e 100 mg/kg aumentou as concentrações de dopamina no CPu e na ATV em ratos adolescentes, mas não em adultos, e no NAc em ambas as idades. Além disso, cafeína causou aumento das concentrações de serotonina no CPFm em ratos adultos, mas não em adolescentes; e na ATV em ambas as idades. Portanto, em ratos adolescentes a cafeína causa estimulação em uma faixa de doses mais ampla que nos adultos. A alteração causada pela cafeína sobre o sistema dopaminérgico é mais evidente em ratos adolescentes do que adultos, enquanto...
Caffeine is the most consumed psychostimulant drug in the world. This drug is present in food, beverages and medicines marketed for individuals of all ages. Despite the great consumption of caffeine containing foods by children and adolescents, few studies investigated age related effects of caffeine. Thus, we investigated caffeine-induced locomotor activity, as well as the effects of caffeine on the dopaminergic and serotoninergic neurotransmission in adolescents and adults rats in areas important for motor behavior. Adolescent (postnatal day 37-40) or adult (postnatal day 70-74) Wistar rats had their locomotor activity registered following intraperitoneal (i.p.) injection of vehicle or caffeine (3, 10, 30, 60 or 120 mg/kg). In other experiment adolescent or adult rats received acute i.p. injections of 30 or 100 mg/kg of caffeine or saline and had the tissue levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin and 5-hydroxiindolacetic acid (5-HIAA) in the nucleus acumbens (NAc), medial pre-frontal cortex (mPFC), caudate putamen (CPu) and ventral tegmental area (VTA) quantified by high performance liquid chromatography (HPLC). Our results showed that 10 and 30 mg/kg of caffeine induced increased locomotor activity in both adolescent and adult rats, while at the higher caffeine doses (60 and 120 mg/kg) only adolescents were stimulated. The acute injection of 30 or 100 mg/kg of caffeine increased dopamine levels in the CPu and VTA in adolescent but not in adult rats, and in NAc in both ages. Furthermore, caffeine caused an increase in the concentration of serotonine in mPCF in adult but not in adolescent rats, and in VTA in both ages. Thus, in adolescent rats caffeine causes stimulation in a wider range of doses than in adults. The changes caused by caffeine on dopaminergic system are most evident in adolescent than adult rats, while... (Complete abstract click electronic access below)
Caffeine is the most consumed psychostimulant drug in the world. This drug is present in food, beverages and medicines marketed for individuals of all ages. Despite the great consumption of caffeine containing foods by children and adolescents, few studies investigated age related effects of caffeine. Thus, we investigated caffeine-induced locomotor activity, as well as the effects of caffeine on the dopaminergic and serotoninergic neurotransmission in adolescents and adults rats in areas important for motor behavior. Adolescent (postnatal day 37-40) or adult (postnatal day 70-74) Wistar rats had their locomotor activity registered following intraperitoneal (i.p.) injection of vehicle or caffeine (3, 10, 30, 60 or 120 mg/kg). In other experiment adolescent or adult rats received acute i.p. injections of 30 or 100 mg/kg of caffeine or saline and had the tissue levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin and 5-hydroxiindolacetic acid (5-HIAA) in the nucleus acumbens (NAc), medial pre-frontal cortex (mPFC), caudate putamen (CPu) and ventral tegmental area (VTA) quantified by high performance liquid chromatography (HPLC). Our results showed that 10 and 30 mg/kg of caffeine induced increased locomotor activity in both adolescent and adult rats, while at the higher caffeine doses (60 and 120 mg/kg) only adolescents were stimulated. The acute injection of 30 or 100 mg/kg of caffeine increased dopamine levels in the CPu and VTA in adolescent but not in adult rats, and in NAc in both ages. Furthermore, caffeine caused an increase in the concentration of serotonine in mPCF in adult but not in adolescent rats, and in VTA in both ages. Thus, in adolescent rats caffeine causes stimulation in a wider range of doses than in adults. The changes caused by caffeine on dopaminergic system are most evident in adolescent than adult rats, while... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Adolescentes, Adultos, Cafeína - Efeito fisiológico, Serotonina, Adolescent, Adult, Caffeine, Psychomotor stimulation, Dopamine, Serotonin
Como citar
POSSI, Ana Paula Marques. Efeitos comportamentais e neuroquímicos agudos da cafeína em ratos adolescentes e adultos. 2010. 73 f. Dissertação (mestrado) - UNESP/UFSCar, Programa Interinstitucional de Pós-Graduação em Ciências Fisiológicas, 2010.