Epigenetics: What Happens in Vegas Does NOT Stay in Vegas
Grazielle Noro
Loucura, sorte, azar, romance, orgies, luxury... Las Vegas is the perfect stage for experiencing intense experiences full of emotions. For this reason, “What happens in Vegas stays in Vegas” has become a well-known slogan serving us as a manumission for the intense activation of the senses, the well-known pleasure pathways, dopamine, epinephrine, noradrenaline discharges, among others.
_cc781905-5cde-3194-bb3b-136bad5cf58d of science – Epigenetics. What happens in Vegas doesn't seem to stay in Vegas, but takes place directly “under the skin” as author Steve Hyman (2009) states in “How adversity gets under the skin?”
_cc781905-5cde-3194-bb3b-136bad5cf58 . Everyday life seems, however, to place several facets of Las Vegas at our disposal. Sometimes at lower intensity and higher frequency, but activating our organism, our neurobiological structures in the same way. Thus, Epigenetics surprises us by the intensity and seriousness of the consequences of our abusive acts, but also by the good news that proactive, healthy and empathetic behaviors seem to shape who we are in a deeper way_cc781905-5cde-3194- bb3b-136bad5cf58d_e longer than we imagined.
O termo Epigenética foi definido por Conrad Waddington, em 1942, como um ramo of biology that studies how external and environmental factors can produce “heritable” changes over several generations without altering the sequence of genes, which we know as DNA. However, probably due to the technology available for research, only in the last decade has the field of Epigenetics been explored by several researchers.
Um dos experimentos epigenéticos mais amplamente reproduzidos cientificamente avalia o desenvolvimento da vulnerabilidade ao estresse . The physiological response to stress evaluated in these experiments involves activation of the HPA axis (hypothalamus-pituitary-adrenal) in the face of an event considered a stressor by sending chemical messages – neurotransmitters. Among the neurotransmitters involved in the emission of the stress response, corticotropic hormone (CRH), catecholamines (epinephrine and norepinephrine), glucocorticoids (cortisol, corticosterone and cortisone), and GABA (aminobutyric acid) play a fundamental role. CRH and catecholamines act as excitators of the central nervous system, while glucocorticoids are related to the reestablishment of homeostasis and GABA with the inhibition of the central nervous system. In addition, glucocorticoids and GABA act in biofeedback, signaling a reduction in the production of CRH and catecholamines. When not synthesized, the physiological response to a stressor event is more quickly activated and lasts longer in the body.
_cc781905-5cde-3194-bb3b-136bad5cf58d model vulnerability to care between experimental stress that evaluates_ mothers, birthing rats classified as “good mothers” and “deficient mothers” according to the frequency of licking and caressing (licking and grooming) and suckling their pups with an arched back nursing. A cross-adoption procedure was performed with two of the 10 pups from each mother, that is, 8 pups received maternal care from the biological mother while 2 pups were adopted by the other mother and vice versa. The results showed a faster and more intense activation of the HPA axis in the offspring of “poor mothers” even with those born to “good mothers” and vice versa. The following generations, of grandchildren and great-grandchildren, presented the same characteristics according to the maternal care received. Therefore, it was observed that maternal care interferes with the neurodevelopment of the HPA axis and, therefore, with the physiological response to a stressful event.
How does this transmission of behavior-related traits occur from generation to generation once the genetic code is unchanged? Was Lamarck correct in his claims about the influence of the environment on genetics?
In the case of the reported study, observations of the offspring's genome showed changes in the expression of GRs (glucocorticoid) promoter genes as well as GABAergic receptor promoters. Both types of genes underwent DNA methylation or histone deacetylation. The addition of the methyl group to DNA or the loss of the acetyl group on histones (proteins that surround DNA) enhance the condensation of the DNA strand and thus prevent mRNA transcription as well as its translation – necessary for protein synthesis. In other words, the genes were silenced. The low production of glucocorticoids and GABA characterize a behavioral profile vulnerable to stressful events.
In humans, similar epigenetic mechanisms have been observed in studies of maltreatment and neglect in early childhood and related to neurodevelopment on the autism spectrum, schizophrenia, high risk of suicide, Alzheimer's disease, Major Depressive Disorder, Bipolar and Borderline Personality Disorder between others.
Epigenetic mechanisms occur throughout life and are reversible. Psychotherapy has been investigated as an alternative for environmental change that participates in alterations in our epigenome. Positive social contact, meditation, voluntary work, changing habits and beliefs are also related to the changes we can make in our history. Write it down! Your genes are not your destiny