Sex differences in role of estradiol in recovery of function after cerebellar damage
Jervia Mia Powell1, LeMarcus Echoles2,4, Chyna-Rae Dearman3, Lainy B. Day3,4
1Mississippi INBRE Research Scholar, Department of Chemistry & Physics, Alcorn State University, Lorman, MS
2Department of Psychology, University of Mississippi, Oxford, MS
3Department of Biology, University of Mississippi, Oxford, MS
4Neuroscience minor, University of Mississippi, Oxford, MS
Estradiol is neuroprotective. In the brain, estradiol can be synthesized from testosterone via aromatase provisioning glia cells. Previously, we found that cerebellar lesions produced deficits in coordination and procedural learning in zebra finches, as they do in mammals. Further, we found that aromatase inhibition enhanced and estradiol reduced cerebellar induced deficits in spatial learning, but had no effect on coordination deficits. Given that zebra finch females upregulate aromatase more than males after cerebellar lesions and have more circulating estradiol, we predicted that females would recover better than males after cerebellar lesions. We lesioned the cerebellum of male and female zebra finches, with or without simultaneous injection of the aromatase inhibitor, letrozole. As found previously, only birds with cerebellar lesions and aromatase inhibition, not those injected with the saline vehicle, had impairments in our spatial task compared to sham lesioned birds. However, sexes performed similarly. These results support our hypothesis that aromatase improves spatial memory deficits after cerebellar lesions, and together with our prior work suggests this is due to estradiol synthesis. The lack of sex differences is quizzical and could imply that local conversion of testosterone to estradiol is as important as circulating estradiol for neuroprotection and that the greater level of aromatase upregulation in females may be a compensation for their lower level of aromatizable substrate (testosterone). More work is needed to understand the roles of neurosteroidogenesis and brain steroid receptor regulation in neuroplasticity. Analysis of the motor task is still in progress.