Mancera Juan Miguel, Vargas-Chacoff Luis, García-López Angel, Kleszczyńska Agnieszka, Kalamarz Hanna, Martínez-Rodríguez Gonzalo, Kulczykowska Ewa
Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
Comp Biochem Physiol A Mol Integr Physiol. 2008 Jan;149(1):92-7. doi: 10.1016/j.cbpa.2007.10.016. Epub 2007 Nov 7.
Arginine vasotocin (AVT) and isotocin (IT) levels in plasma and pituitary, and melatonin (MEL) levels in plasma were determined in gilthead sea bream (Sparus auratus) subjected to two different types of stress: i) high density (HD) and ii) food deprivation (NF: non-fed). Fishes were randomly assigned to one of 4 treatments that lasted for 14 days: 1) fed fish under normal low density (ND, 4 kg m(-3)); 2) non-fed (NF) fish under ND; 3) fed fish under high density (HD, 70 kg m(-3)); and 4) non-fed fish under HD. Ten fish from each tank were anaesthetized, weighed and plasma and pituitary samples were taken. Plasma and pituitary AVT and IT content were determined by HPLC, while plasma MEL was assayed by RIA. Plasma AVT and IT values were enhanced in all fish kept at high density. The response of AVT was much stronger than that of IT. The highest pituitary AVT and IT levels were shown in NF fish kept at normal density. The significantly higher plasma MEL levels were measured in fed fish kept at HD. These results suggest a role of AVT, IT and MEL in response of sea bream to a common stress factor, high density. Although food deprivation does not influence AVT and IT plasma levels, it seems to affect hypothalamic synthesis of nonapeptides. Further studies are required to elucidate the complex role of AVT, IT and MEL in the sea bream's response to different stress stimuli.
测定了处于两种不同应激类型下的金头鲷（Sparus auratus）血浆和垂体中的精氨酸加压催产素（AVT）和异催产素（IT）水平，以及血浆中的褪黑素（MEL）水平：i）高密度（HD）和ii）饥饿（NF：未喂食）。将鱼随机分配到4种处理之一，持续14天：1）正常低密度（ND，4 kg m(-3)）下喂食的鱼；2）ND下未喂食（NF）的鱼；3）高密度（HD，70 kg m(-3)）下喂食的鱼；4）HD下未喂食的鱼。对每个水箱中的10条鱼进行麻醉、称重，并采集血浆和垂体样本。通过高效液相色谱法测定血浆和垂体中的AVT和IT含量，而通过放射免疫分析法测定血浆中的MEL。所有处于高密度环境下的鱼的血浆AVT和IT值均升高。AVT的反应比IT强烈得多。正常密度下未喂食的鱼垂体中AVT和IT水平最高。在高密度下喂食的鱼中测得的血浆MEL水平显著更高。这些结果表明AVT、IT和MEL在金头鲷对常见应激因素——高密度的反应中起作用。尽管饥饿不影响血浆中AVT和IT的水平，但似乎会影响下丘脑九肽的合成。需要进一步研究以阐明AVT、IT和MEL在金头鲷对不同应激刺激反应中的复杂作用。
