Catherine S. Woolley

Bruce McEwen at Rockefeller University studies stress and its impact on the brain.[16] With McEwen, Woolley initially studied neuroleptics and their effects on proenkephalin mRNA levels.[5] Woolley went on to work with McEwen and Elizabeth Gould on a 1990 study that examined the brain using Golgi's method,[5][6][17] a technique first described by Camillo Golgi in 1873.[18] The study showed that estradiol increased the number and density of excitatory synapses of CA1 pyramidal cells in the rat hippocampus, as well as the density of dendritic spines. Both estradiol and spine density fluctuated dramatically during the estrous cycle.[5][6][17] Woolley recognized that this suggested that the adult brain was subject to change, at least in rats; this was surprising because it was accepted at that time that the adult brain was structurally stable.[5][12][16] Woolley's 1990 work is considered a pioneering study in hormones and synaptic plasticity.[6] Further work established that the manipulation of female sex hormones affects hippocampal structure in adult rats.[6][19]

Between 1993 and 1998, Woolley worked as a postdoc at the University of Washington in Seattle, with Philip Schwartzkroin. There she applied electrophysiology techniques and ultrastructural analysis to the study of hormonal effects in the brain.[5][20][21] She studied the effects of estrogen on the release of GABA in the hippocampus.[22] In 2000, she received the Cortical Explorer Award in recognition of her work on neuroanatomy and brain activity.[5]

"Catherine is finding the same neuronotrophic activation by steroids whether she uses Golgi staining to count spines or the electron microscope to visualize synapses. The methods are more sophisticated and powerful, but the basic observation is the same." Cortical Explorer Award, 2000[5]

As a professor at Northwestern University, Woolley has done ongoing research into the sex-specific effects of estrogens, GABAA receptors, metabotropic glutamate receptors, and endogenous cannabinoids and their roles as neuromodulators of brain development and function.[23][24][25] In 2012, Woolley published research showing that estrogens had differential effects in the brains of female and male rats, decreasing inhibitory synaptic transmission in female rats but not in males.[3][26] In 2015, her group reported that male and female rats differ in the molecular pathways affected by endocannabinoids. In female rats the drug URB-597 increased the inhibitory effect of the endocannabinoid anandamide, lessening the release of neurotransmitters. In male rats, the drug had no effect. The interaction did not reflect circulating reproductive hormones.[3] Further research is needed to determine the extent to which rat neurology provides an accurate model for human neurology.[3][9]

While the significance of these results for humans are not yet demonstrated, rats are often used as a model for studying humans. An important implication of Woolley's research is that drug testing on males should not be assumed to yield results applicable to both males and females. To understand drug action, effects on both sexes should be studied.[3][7][9]