One of the main principles upon which Psychology is founded is the concept that childhood experiences shape an individual’s personality and behavior throughout the lifespan. Research shows that this is not a phenomenon that is limited to humans, and through animal study a greater spectrum of understanding is emerging surrounding the impact of stress and pharmacological treatment in developing organisms.
The Bolanos Laboratory at Florida State University is one lab looking to answer these questions concerning the impact of stress and drug treatment on the developing brain. Recent studies conducted in the lab have shown the impact of the a specific transcription factor in the brain, the extra-cellular signal regulated kinase (ERK), on the modulation of depressive behaviors.
Depression has a huge impact on brain function, most prominently in those regions that play a role in the regulation of mood-associated neurotransmitters. The monoamine neurotransmitters (dopamine, serotonin, and norepinepherine), are those most closely associated with the regulation of mood and the modulation of depression. The mesolimbic-dopamine pathway is a circuit of brain areas with many dopamine receptors; this circuit is associated with rewarding stimuli (drugs of addiction are often studied in association with the mesolimbic-dopamine pathways) as well as stressful stimuli. The pathway then is the brain’s main concourse for the development of the basic emotional responses of elation and depression.
The ventral tegmental area (VTA) is the brain region in which the dopminergic cells of the pathway originate, and this is the region in which the manipulation of ERK activity has been shown to produce distinct behavioral phenotypes. When researchers virally increased the phosphorylation of ERK in the VTA they found that it produced a behavioral profile similar to that of stress-induced depression. When ERK phosphorylation was decreased the behavior of the animals was similar to those that had received antidepressant treatment.
While this research raises a great deal of questions concerning the nature of the development of depression and the ways in which depressive disorders are treated pharmacologically it also confirms the role of dopminergic systems in the modulation of depressive symptoms and marks ERK and its downstream targets as major components in the regulation of depressive symptomatology.
- Davis LC, Warren BL, Iñiguez SD, Bolaños-Guzmán CA (2009). Short- and Long-term neurobiological effects of concomitant methylphenidate and fluoxetine exposure during adolescence in male rats. Society for Neuroscience, Chicago, IL.
• Davis LC, Bolaños-Guzmán CA (2009). Short- and long-term neurobiological consequences of antidepressant exposure in preadolescent female rats. Undergraduate Research Fall Symposium, Florida State University, Tallahassee, FL.
- Iñiguez SD, Vialou V, Wilkinson MB, Warren BL, Lobo MK, Neve RL, Nestler EJ, Bolaños-Guzmán CA (2009). Fluoxetine Exposure During Adolescence Regulates Behavioral and Extracellular Signal-Regulated Kinase (ERK) Activity in the Ventral Tegmental Area of Male Rats. Society for Neuroscience, Chicago, IL.
- Iñiguez SD, Warren BL, & Bolaños-Guzmán CA (2010). Short- and Long-term Functional Consequences of Fluoxetine Exposure During Adolescence in Male Rats. Biological Psychiatry, 67, 1057-1066.
- Iñiguez SD, Vialou V, Warren BL, Cao J-L, Alcantara LF, Davis LC, Manojlovic Z, Neve RL, Russo SJ, Han MH, Nestler EJ, & Bolaños-Guzmán CA (2010) Extracellular Signal-Regulated Kinase-2 Within the Ventral Tegmental Area Regulates Responses to Stress. Journal of Neuroscience, 22, 7652-7663.