多巴胺对长爪沙鼠贮食行为的影响

Effect of dopamine on food-hoarding in Mongolian gerbils(Meriones unguiculatus)

长爪沙鼠的贮食行为具有高低二型性。禁食诱导的贮食行为可能与中脑多巴胺(Dopamine,DA)系统有关,但尚乏证据。本文通过Fos标记相关脑区的活性,酪氨酸羟化酶(TH)标记DA神经元,以免疫组化方法观察对高贮食组长爪沙鼠腹腔注射DA拮抗剂haloperidol(1 mg/kg)和对低贮食组长爪沙鼠腹腔注射DA激动剂apomorphine(0.3 mg/kg)的行为和神经变化,验证中枢DA对贮食行为的调节。结果显示,haloperidol抑制了禁食诱导的沙鼠的贮食行为,这种抑制刺激了伏隔核和尾壳核Fos-ir阳性细胞表达,但却降低了黑质区Fos-ir和Fos-ir/TH-ir的细胞表达。Apomorphine增加了禁食诱导的沙鼠的贮食行为,降低伏隔核和尾壳核Fos-ir阳性细胞表达。这些结果表明,中脑DA系统参与调节了禁食条件下长爪沙鼠的贮食行为。

Food deprivation-induced food-hoarding in Mongolian gerbils（Meriones unguiculatus） shows a bimodal pattern.Although our previous study implicted the neurotransmitter dopamine（DA） in the brain in food hoarding,little is known about how DA is involved in this behavior. Here we tested the effects of the DA receptor antagonist haloperidol or the agonist apomorphine on food-hoarding and neuronal activation indicated by Fos-immunoreactive（ir） labeling in food-deprived males Mongolian gerbils. Males received i. p. injections of haloperidol（1 mg / kg） or apomorphine（0. 3 mg / kg）. Haloperidol treatment inhibited food deprivation-induced increases in food-hoarding in male gerbils displaying high levels of food-hoarding（HFH）. In contrast,apomorphine stimulated this behavior in males displaying low levels of food-hoarding（LFH）. Furthermore,haloperidol significantly increased Fos-ir labeling in the caudate putamen（CP） and nucleus accumbens（NAcc）,but decreased Fos-ir and TH-ir / Fos-ir expression in the substantia nigra（SN）. Conversely,apomorphine decreased Fos-ir labeling in the CP and NAcc. Together,these data indicate that the mesolimbic dopamine system is involved in mediating food-hoarding behavior induced by food deprivation.