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Preproenkephalin mRNA is Regulated by an Interaction Between Steroid Hormones and Nociceptive Stimulation
Author(s) -
Holtzman David A.,
Brooks Phillip J.,
Pfaff Donald W.,
SchwartzGiblin Susan
Publication year - 1997
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1046/j.1365-2826.1997.00658.x
Subject(s) - medicine , endocrinology , ovariectomized rat , noxious stimulus , hormone , stimulation , steroid , hypothalamus , chemistry , analysis of variance , nociception , biology , receptor
The expression of preproenkephalin (PPE) mRNA has previously been shown to be regulated by steroid hormones in the ventromedial nucleus of the hypothalamus (VMH) and to be regulated by noxious stimuli in the dorsal horn of the spinal cord (DH). The present in situ hybridization study in ovariectomized rats showed that PPE mRNA expression in both the VMH and the lumbar DH, responds to the interaction between a noxious peripheral stimulus and ovarian steroid hormones. In the VMH, either estradiol or estradiol+progesterone increased the mean PPE mRNA content per cell by 100% compared with vehicle‐treated rats. Unilateral hindpaw injection of 5% formalin, as compared to saline, significantly increased mean PPE mRNA content per VMH cell in rats treated with vehicle or estradiol but not those treated with estradiol+progesterone. Regression analysis for mean PPE mRNA content per VMH cell as a function of intensity of hindpaw inflammation showed a significant positive correlation coefficient after vehicle and estradiol treatment (P<0.02) but a strong trend towards a negative correlation coefficient after estradiol+progesterone treatment (P<0.06). ANOVA for homogeneity of regression coefficients showed a significant difference across hormone groups (P<0.01).