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Effects of morphine on prolactin receptors in the rat brain
Author(s) -
Lai Zhennan,
Zhai Qingzhu,
Yukhananov Rustam,
Larsson Christer,
Roos Paul,
Kreek Mary Jeanne,
Nyberg Fred
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)80366-8
Subject(s) - prolactin , medicine , endocrinology , hypothalamus , choroid plexus , hormone , morphine , chemistry , receptor , binding site , secretion , central nervous system , biology , biochemistry
The effect of chronically given morphine on the binding of ovine prolactin (oPRL) to specific areas in the male rat brain was studied. The drug was delivered through subcutaneously implanted miniosmotic pumps. The results indicated that the density of prolactin binding sites in the hypothalamus and the choroid plexus was significantly decreased in the acute phase of morphine administration but restored to control levels when tolerance to morphine was developed. The decrease in prolactin binding was contrasted by elevated plasma levels of the hormone. A negative correlation was found between the hormone concentration in plasma and the density of its binding sites in the hypothalamus and choroid plexus. The hormone‐binding sites in these two regions were further characterized with regard to binding constants and molecular sizes. The relevance of the present results with respect to the hypothalamic control of prolactin secretion is discussed.