BACKGROUND: Low concentrations of inhaled anesthetics present in the early postoperative period can increase @entity158 sensitivity. Changes in @entity158 threshold associated with inhaled anesthetics have been reported in male @entity19 , @entity35 , and @entity1 . METHODS: The authors compared the @entity158 -enhancing effects of @entity5161 in male and female @entity19 in response to a thermal stimulus and studied the consequences of hormonal manipulation. RESULTS: @entity5161 produced a larger increase in @entity158 sensitivity in female @entity19 . Both castration and oophorectomy resulted in an increase in baseline @entity158 sensitivity and potentiated @entity158 enhancement by @entity5161 . At stages of the estrus cycle when @entity172 was low, female @entity19 showed greater @entity158 enhancement from @entity5161 than at high @entity172 stages. Treatment with exogenous @entity172 reduced @entity5161 -induced @entity158 sensitivity. Exogenous @entity251 treatment had a similar effect, which did not occur when enzymatic conversion to @entity172 was prevented. CONCLUSIONS: Because both @entity172 and @entity251 reduce the pronociceptive action of @entity5161 , intact females may exhibit a larger increase in @entity158 sensitivity because of their cyclical @entity172 levels. @entity251 is effective in the male because of conversion to @entity172 . Enhanced @entity158 sensitivity is clearly undesirable in the postoperative setting. If these findings also apply to @entity1 , the menstrual cycle may be an important factor in determining @entity158 levels after emergence from general anesthesia.

Pronociceptive actions of @entity5161 : a protective role for XXXX .

@entity1 :: ('9606', 'Species') :: ['humans'] @entity172 :: ('MESH:D004967', 'Chemical') :: ['estrogen'] @entity251 :: ('MESH:D013739', 'Chemical') :: ['testosterone', 'Testosterone'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity158 :: ('MESH:D010146', 'Disease') :: ['pain'] @entity35 :: ('10116', 'Species') :: ['rats'] @entity5161 :: ('MESH:D007530', 'Chemical') :: ['Isoflurane', 'isoflurane']
@entity172 :: (MESH:D004967,Chemical) :: ['estrogen']
