长期以来认为,动物组织中的内源性阿片类物质都是长链的阿片肽前体:前阿黑皮素(proopiocortin)、前脑啡肽(proenkephalin)或前强啡肽(prodynorphin)的片段,而非肽类的吗啡仅存在于植物中。Spector 及其同事用放射免疫测定法从蟾蜍皮肤中检测出低浓度的吗啡(3 pmol/g)。Goldstein 实验室也从牛的下丘脑及肾上腺检测出吗啡。他们指出,所发现的极少量的吗啡是属于内源性物质还是来自外界,仍不清楚。因此,决定证明吗啡的生物合成。Spector 实验室和 Goldstein 实验室都发表了进一步分析内源性非肽类阿片样物质的实验结果。Goldstein 等发现吗啡和可待因存在于牛下丘脑提取物中;但在牛肾上腺及大鼠脑提取物中则无规律可循。所以不能断定吗啡和可待因是否为内源性物质、是否参与脑功能。Spector 等从大鼠脑 It has long been believed that endogenous opioids in animal tissues are long chain opioid precursors: proopiocortin, proenkephalin or prodynorphin , Whereas non-peptide morphine is found only in plants. Spector and coworkers detected low concentrations of morphine (3 pmol / g) from skin of toad by radioimmunoassay. Goldstein Labs also detected morphine from the hypothalamus and adrenal glands of cattle. They pointed out that the very small amount of morphine found was either endogenous or from the outside world and remains unclear. Therefore, it is decided to prove the biosynthesis of morphine. Both Spector and Goldstein Laboratories have published experimental results for further analysis of endogenous non-peptide opioids. Goldstein et al found that morphine and codeine were found in bovine hypothalamic extracts; however, there was no regular pattern in bovine adrenal and rat brain extracts. Therefore, it can not be concluded whether morphine and codeine are endogenous substances and whether they are involved in brain function. Spector et al. From the rat brain