Pal P, Raj S S, Mohan M, Pal G K
Department of Physiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry.
Indian J Physiol Pharmacol. 2000 Jan;44(1):24-32.
Nucleus accumbens is proposed as one of the centers in the neural circuitry involved in the regulation of feeding and drinking behaviour in rats. Injection of dopamine and angiotensin-II into this nucleus has been documented to affect water and food intake in rats. Reports on the effect of intracerebral injection of catecholamines on feeding and drinking behaviour in animal models are conflicting. Therefore, in the present study the effect of adrenaline and noradrenaline injected into nucleus accumbens on food and water intake in rats was assessed. 24 h basal food and water intakes were recorded in Wistar rats and were found to be 12.3 +/- 0.46 g and 21.7 +/- 1.03 ml respectively. Stainless steel cannulae were implanted stereotaxically into the nucleus accumbens. Four different doses (0.1 microgram, 0.5 microgram, 1 microgram, and 2 micrograms) of adrenaline and noradrenaline were injected into the nucleus accumbens through the implanted cannulae in different group of animals and their 24 h food and water intakes were recorded following these injections. No change in food and water intake was observed following the administration of different doses of adrenaline. A significant increase in 24 h water intake reaching a maximum of 28.88 +/- 1.45 ml at 1 microgram dose, without change in food intake was observed following administration of different doses of noradrenaline. The noradrenaline-facilitated water intake was blocked when noradrenaline was injected following injection of phentolamine, an alpha-receptor blocker. The bilateral lesions of nucleus accumbens resulted in a significant and sustained inhibition of water intake (16.61 +/- 0.67 ml) without change in food intake. These observations suggest that noradrenaline facilitates water intake without affecting food intake when injected into the nucleus accumbens in rats and the dipsogenic effect of noradrenaline is mediated by alpha-receptors. Adrenaline does not affect these ingestive behaviours when injected into the nucleus accumbens in rats.
伏隔核被认为是参与调节大鼠摄食和饮水行为的神经回路中的中心之一。已证明向该核内注射多巴胺和血管紧张素II会影响大鼠的水和食物摄入量。关于脑内注射儿茶酚胺对动物模型摄食和饮水行为影响的报道相互矛盾。因此，在本研究中，评估了向伏隔核注射肾上腺素和去甲肾上腺素对大鼠食物和水摄入量的影响。记录了Wistar大鼠24小时的基础食物和水摄入量，分别为12.3±0.46克和21.7±1.03毫升。通过立体定位将不锈钢套管植入伏隔核。在不同组的动物中，通过植入的套管向伏隔核注射四种不同剂量（0.1微克、0.5微克、1微克和2微克）的肾上腺素和去甲肾上腺素，并在注射后记录它们24小时的食物和水摄入量。注射不同剂量肾上腺素后，未观察到食物和水摄入量的变化。注射不同剂量去甲肾上腺素后，观察到24小时水摄入量显著增加，在1微克剂量时达到最大值28.88±1.45毫升，而食物摄入量没有变化。当注射α受体阻滞剂酚妥拉明后再注射去甲肾上腺素时，去甲肾上腺素促进的水摄入量被阻断。伏隔核的双侧损伤导致水摄入量显著且持续受到抑制（16.61±0.67毫升），而食物摄入量没有变化。这些观察结果表明，向大鼠伏隔核注射去甲肾上腺素时，去甲肾上腺素促进水摄入而不影响食物摄入，并且去甲肾上腺素的致渴作用是由α受体介导的。向大鼠伏隔核注射肾上腺素时，不会影响这些摄食行为。
