Expression Of Neurokinin B In The Reproductive Axis Of Canine

Nurokinin B (NKB) is a kind of polypeptide which contains ten amino acids belonging to the family of tachykinin. NKB has a lot of biology functions such as activation of blood vessels, stabilizing heart rate and reducing the mean arterial pressure. Researchers in recent years reported that NKB was closely related to animal reproduction. Currently, it, however, is just restricted to rodents, people, monkeys, sheep, pigs, poultry and other species, there's no report for canine species. Adult female (n=3) and male (n=3) canine, immunohistochemistry technique was used to detect the distribution of NKB in the reproductive axis of adult canines, and infantile (1.5M), childhood (4M), and puberty (7.5M) female canine and adult (24M) canine (n=4) were used for RT-PCR to detect the quantity of Tac3 mRNA (NKB) in the reproductive axis of female canines during different development stages. Aim to initially elaborate the expression pattern of NKB in the reproductive axis of canine.The results showed that (1) varying degrees of NKB immune positive cells distributed in the reproductive axis of adult canine; ?they were mainly distributed in the lateral hypothalamic area (LHA) and supraoptic nucleus (SON) of hypothalamus; ? general immune positive cells were found in the adenohypophysis, while negative in the neurohypophysis; ?it was also found in the granular layer, follicular theca, ovocyte and interstitial substance in each level follicle of ovary; ?in testis, immune positive cells were mainly distributed in the interstitial tissue and spermatogenic cells. (2) the mainly change regulations of Tac3 mRNA quantity in the reproductive axis of female canine were that: ?no matter what tissue, its quantity always increased from baby to puberty stage, then decreased at adult stage, and the quantity changes of each tissue from baby to adult stage were significant different (P<0.05); ?and no matter at which development stage, tissues of the highest level of quantity were always pituitary. Quantity among tissues at infantile stage had no significant difference (P>0.05); at childhood stage, quantity difference between hypothalamus and pituitary was not significant (P>0.05), whereas very significant difference between ovary and hypothalamus (P<0.01), pituitary (P<0.01); Quantity in the hypothalamus was significant lesser than that in the pituitary (P<0.05) or ovary (P<0.01) at puberty stage, meanwhile no significant difference between pituitary and ovary (P>0.05); they all had very significant differences with each other tissue at adult stage (P<0.01).Conclusion made from above research:(1) varying degrees of NKB immune positive cells distributed in the hypothalamus, adenohypophysis, ovary, and testis of adult canine illustrated that it may regulate reproduction of canine. (2) the trend of Tac3 mRNA in the axis of female canine increased from infantile to puberty stage, all achieved top level at puberty stage, and then decreased at adult stage suggested NKB may participate in the puberty launching of female canine.