Abstract:

【Objective】This study was carried out to obtain sequence of NPS and NPSR gene, and reveal the expression of NPS and NPSR mRNA in rabbit organs and influence of heat stress on expression of NPS/NPSR mRNA in the hypothalamus- pituitary- adrenal(HPA) axis. 【Method】The complete coding sequence (CDS) of NPS and partial CDS of NPSR were obtained from rabbit brain using the approach of gene cloning. The expression of NPS and NPSR mRNA in rabbit organs and influence of heat stress on expression of NPS/NPSR mRNA in the hypothalamus-pituitary-adrenal axis were studied by semi-quantitative RT-PCR. 【Result】The length of NPS and NPSR were 270 bp and 847 bp, respectively. The sequences of the products were confirmed to be those of NPS and NPSR in rabbit and enrolled in GenBank(accession numbers:EU978456 and FJ713102). Amino sequece of rabbit NPS precursor had high homology compared with other animals. Phylogenetic analysis showed that amino sequence of rabbit NPS precursor had high homology compared with rat and mouse consistent with species evolution relationship. The expression of NPS and NPSR mRNA was extensive in rabbit organs, with majority in the central nervous system, thyroid gland, salivary gland and mammary gland. After the heat stress NPS mRNA expression level in the hypothalamus and the adrenal gland increased gradually and followed by a downward trend afterwards, that is, it reached the highest at 1 h and 0.5 h compared with the control and showed a significant difference (P＜0.01), and followed by decline at 2 h. In the pituitary the
experimental group showed a downward trend and showed a significant difference compared with the control (P＜0.01). NPSR mRNA expression patterns in the hypothalamus- pituitary-adrenal axis was similar to that of NPS during heat stress compared with the control. 【Conclusion】NPS and its receptor gene in rabbit were conservative, the expression of NPS and NPSR mRNA in rabbit organs were extensive and the expression of NPS and NPSR mRNA in HPA changed when rabbit was suffered from heat stress.