The Role And Regulation Of The Hypothalamic Lateral Nucleus And The Nucleus Accumbens Orexin Neurons In Rat Fructose Overeating

Objective: To investigate whether the rats given glucose in the intermittent access model(IAM) can cause hedonic feeding including bingeing,and the influence of nucleus accumbens and lateral hypothalamic(LHA) orexin(ORX)neurons on fructose eating behavior,and the effect of fructose bingeing on dopamine receptor of nucleus accumbens.Method: The IAM rats were given 4 %,8 % or 12 % fructose or Saline(NS). And the fructose intake and fructose eating behavior were observed and recorded in the rats. The receptors number(Bmax) and receptor affinity(Kd) of dopamine D1 R and D2 R were analyzed in the nucleus accumbens shell, nucleus accumbens core and dorsal striatum. The C-Fos neurons immunoreactivity(Fos-IR)were recorded in paraventricular nucleus, amygdala, nucleus accumbens of related nucleus of the long-term and short-term IAM rat. Food intake was observed while administration of OX1 R antagonist SB334867 in the long term IAM rats at 22 day.Results: The rats given fructose solutions displayed fructose bingeing but unaltered DA D1 R or D2 R number following long-term exposure to the IAM(P>0.05). Fructose bingeing rats, as compared to chow bingeing controls, exhibited reduced nucleus accumbens neuron activation, as determined by c-Fos-immunoreactivity(P<0.05). Following short-term access to the IAM, rats exhibited bingeing but unchanged Fos-IR(P>0.05). The food intake were significantly reduced while OX1 R antagonist SB-334867 were administrated at 22 days in the IAM rats(P<0.05).Conclusion: The rats given fructose solutions displayed fructose bingeing but unaltered DA D1 R or D2 R number following exposure to the IAM. Long term IAM experiment can change the activation state of related central nervous system in rats. Long term IAM experiment to reduce the activity of neurons in the nucleus accumbens,and enhance the activity of the neurons in the lateral nucleus of the nucleus. OX1 R antagonist SB-334867 can reduce the fructose and food intake of the rats.