Endocrine Role of OFQ/N: Studies with Knock-out Mice

描述（由申请方提供）：待检验的假设是OFQ/N在催乳素分泌的调节中起生理学上重要的作用，并且它在下丘脑水平发挥这种控制作用，特别是通过抑制结节漏斗多巴胺能神经元。为了实现这一目标，将在这些拟定研究中使用雄性和雌性OFQIN敲除小鼠及其野生型和杂合同窝仔。由于哺乳是催乳素释放的一种有效和重要的生理刺激，因此将确定哺乳诱导的催乳素增加。如果OFQ/N对这种反应很重要，那么在OFQ/N敲除小鼠中，吸吮诱导的增加将减弱。此外，OFQIN给药将刺激催乳素释放并增强哺乳诱导的增加，即使在基因敲除中也是如此，因为它们仍然表达受体。然而，补偿机制发生的可能性，例如由于其他阿片肽的作用，将通过用阿片受体拮抗剂或抗血清预处理小鼠以消除其他内源性阿片剂中的每一种来解决。通过在雄性和雌性小鼠中进行剂量反应研究，确定催乳素分泌反应对OFQIN敏感性的性别差异。将确定OFQIN受体在敲除小鼠中发挥功能的能力，所述敲除小鼠在不存在肽的情况下发育和成熟。最后，通过定量测定正中隆起和其他脑区的特定胺，特别是多巴胺，来确定神经作用机制，本研究的长期目标是了解催乳素分泌的神经调节，特别是不同内源性阿片肽及其受体之间的相互作用。催乳素具有许多重要的生理作用。它参与生殖，并在介导应激反应，免疫活性和维持稳态方面发挥重要作用。为了了解生殖和压力相关的疾病，重要的是要了解催乳素释放的神经化学调节。

DESCRIPTION (provided by applicant): The hypothesis to be tested is that OFQ/N plays a physiologically significant role in the regulation of prolactin secretion and that it exerts this control at the hypothalamic level, specifically by inhibiting the tuberoinfundibular dopaminergic neurons. To accomplish this goal, male and female OFQIN knockout mice, and their wild type and heterozygous littermates, will be used in these proposed studies. The suckling-induced prolactin increase wifl be determined since suckling is a potent and important physiological stimulus for prolactin release. If OFQ/N is important for this response, then the suckling-induced increase will be attenuated in OFQ/N knockout mice. Furthermore, OFQIN administration will stimulate prolactin release and enhance the suckling-induced increase, even in knockouts because they still express the receptors. However, the possibility that compensatory mechanisms occur, e.g. due to the actions of other opiate peptides will be addressed by pretreating mice with opiate receptor antagonists or antiserum to eliminate each one of the other endogenous opiates. Sex differences in the sensitivity of the prolactin secretory response to OFQIN will be determined by conducting dose response studies in male and female mice. The ability of the OFQIN receptor to function in knockout mice, that develop and mature in the absence of the peptide, will be determined. Finally, the neural mechanism of action will be determined by quantifying specific amines, particularly dopamine, in the median eminence and other select regions of the brain.The iong term objective of this research is to understand the neural regulation of prolactin secretion, particularly the interaction among the different endogenous opiate peptides and their receptors. Prolactin has a number of important physiological roles. It is involved in reproduction, as well as being important in mediating the stress response, immunocompetence and maintaining homeostasis. To understand reproductive and stress-related disorders, it is important to understand the neurochemical regulation of prolactin release.