When Herminia Pasantes Ordóñez was about 14 years old, in 1950, she heard her mother tell her father that she would never find a husband. Pasante had to wear thick glasses for her poor eyesight. In her mother’s eyes, those glasses meant that her future as a “good wife” was doomed. “It made my life easier,” says Pasantes, “because it was already said that I was going to study.”
At a time when it was unusual for women to become scientists, Pasantes studied biology at the National Autonomous University of Mexico in Mexico City, or UNAM. She was the first member of her family to go to college.
She became a neurobiologist and one of the most important Mexican scientists of her time. Her studies on the role of the brain chemical taurine provide deep insights into how cells maintain their size – essential for proper function. In 2001, she became the first woman to win Mexico’s National Prize for Sciences and Arts in the field of physical, mathematical and natural sciences.
“We basically learned about cell volume regulation through Herminia’s eyes and work,” says Alexander Mongin, a Belarusian neuroscientist at Albany Medical College in New York.
Pasantes got married in 1965 while doing her master’s in biochemistry at UNAM. She had a daughter in 1966 and a son in 1967 before starting a Ph.D. in natural sciences in 1970 at the Center of Neurochemistry at the University of Strasbourg in France. There, she worked in the laboratory of Paul Mandel, a Polish pioneer in neurochemistry.
The lab was trying to find out everything there was to know about the retina, the layer of tissue at the back of the eye that is sensitive to light. Pasantes decided to test whether free amino acids, a group not included in proteins, were present in the retina and brain of rats. Her first chromatography – a laboratory technique that allows scientists to separate and identify the components of a sample – showed a large amount of taurine in both tissues. Taurine would lead the rest of her scientific career, including work in her own laboratory, which she started around 1975 at the Institute of Cell Physiology at UNAM.
Taurine is found to be widely distributed in animal tissues and has various biological functions, some of which were discovered by Pasantes. Her research found that taurine helps maintain cell volume in nerve cells and that it protects brain, muscle, heart and retinal cells by preventing the death of stem cells, which give rise to all the specialized cells in the body.
Contrary to what most scientists believed at the time, taurine did not function as a neurotransmitter that sent messages between nerve cells. Pasantes first demonstrated that it functioned as an osmolyte in the brain. Osmolytes help maintain the size and integrity of cells by opening channels in their membranes to let water in or out.
Pasantes says he has spent many years searching for an answer to why there is so much taurine in the brain. “When you ask nature a question, 80 to 90 percent of the time, the answer is no,” she says. “But when the answer is yes, it’s great.”
Pasante’s lab was one of four major labs that did groundbreaking work on regulating cell volume in the brain, Mongin says.
Her work and that of others proved that taurine has a protective effect; this is why the chemical is now sprayed on containers that hold organs for transplant. Pasante’s work was the foundation for our understanding of how to prevent and treat brain edema, a condition where the brain swells due to excessive fluid accumulation, from head trauma or reduced blood supply, for example. She and other experts also reviewed taurine’s role for Red Bull, which added the chemical to its formula because of its potentially heart-protective effects.
Pasantes stopped doing research in 2019 and spends his time speaking and writing about science. She hopes her story speaks to women around the world who want to be scientists: “It’s important to send the message that it is possible,” she says.
Years before being accepted into Mandel’s lab, her application for a Ph.D. in biochemistry at UNAM was rejected. Pasantes says the reason was that she had just given birth to her daughter. Looking back, this moment was “one of the most wonderful things that could have happened to me,” Pasantes says, because she ended up in Strasbourg, where her potential as a researcher blossomed.
Rosa María González Victoria, a social scientist at the Autonomous University of Hidalgo State in Pachuca, Mexico, who specializes in gender studies, recently interviewed Pasantes for a book about Mexican women in science. González Victoria thinks Pasante’s response to that early rejection speaks to the kind of person she is: “A woman who takes those nos and turns them into yeses.”