The expression of preproenkephalin (PPE) mRNA has previously been shown to be regulated by @entity134 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 @entity35 showed that PPE mRNA expression in both the VMH and the lumbar DH, responds to the interaction between a noxious peripheral stimulus and ovarian @entity134 hormones. In the VMH, either @entity53 or @entity53 + @entity1420 increased the mean PPE mRNA content per cell by 100% compared with vehicle-treated @entity35 . Unilateral hindpaw injection of 5% @entity406 , as compared to saline, significantly increased mean PPE mRNA content per VMH cell in @entity35 treated with vehicle or @entity53 but not those treated with @entity53 + @entity1420 . Regression analysis for mean PPE mRNA content per VMH cell as a function of intensity of hindpaw @entity32 showed a significant positive correlation coefficient after vehicle and @entity53 treatment (P < 0.02) but a strong trend towards a negative correlation coefficient after @entity53 + @entity1420 treatment (P < 0.06). ANOVA for homogeneity of regression coefficients showed a significant difference across hormone groups (P < 0.01). In the lumbar DH, mean PPE mRNA content per cell was greater in @entity35 injected with @entity406 than with saline and was greatest in @entity35 given @entity230 + @entity406 . Mean PPE mRNA content per DH cell was greater ipsilateral than contralateral to the @entity406 injection in @entity53 -treated @entity35 , but no laterality difference was seen in the other hormone groups. No significant differences in mean PPE mRNA levels per DH cell were found among the @entity35 treated with saline + hormone, saline + vehicle, @entity406 + vehicle, or uninjected @entity35 . For all hormone groups combined, mean PPE mRNA per DH cell showed a significant positive regression on intensity of hindpaw @entity32 (P < 0.05). Taken together these data are consistent with reports of increased @entity158 threshold during pregnancy, descending control of antinociception from the basomedial hypothalamus and positive correlations between VMH levels of PPE mRNA and @entity1515 , a behavior evoked by somatosensory stimulation below nociceptive threshold.

Preproenkephalin mRNA is regulated by an interaction between XXXX hormones and nociceptive stimulation.

@entity230 :: ('MESH:D013256', 'Chemical') :: ['steroids'] @entity32 :: ('MESH:D007249', 'Disease') :: ['inflammation'] @entity1420 :: ('MESH:D011374', 'Chemical') :: ['progesterone'] @entity406 :: ('MESH:D005557', 'Chemical') :: ['formalin'] @entity53 :: ('MESH:D004958', 'Chemical') :: ['estradiol'] @entity134 :: ('CHEBI:35341', 'Chemical') :: ['steroid'] @entity1515 :: ('MESH:D008141', 'Disease') :: ['lordosis'] @entity158 :: ('MESH:D010146', 'Disease') :: ['pain'] @entity35 :: ('10116', 'Species') :: ['rats']
@entity134 :: (CHEBI:35341,Chemical) :: ['steroid']
