Stress-induced changes in extracellular dopamine and serotonin in the medial prefrontal cortex and dorsal hippocampus of prenatally malnourished rats

Abstract

Prenatal protein malnutrition continues to be a significant problem in the world today. Exposure to prenatal protein malnutrition increases the risk of a number of neuropsychiatric disorders in adulthood including depression, schizophrenia and attentional deficit disorder. In the present experiment we have examined the effects of stress on extracellular serotonin (5-HT) and dopamine in the medial prefrontal cortex and dorsal hippocampus of rats exposed in utero to protein malnutrition. The medial prefrontal cortex and dorsal hippocampus were chosen as two limbic forebrain regions involved in learning and memory, attention and the stress response. Extracellular 5-HT and dopamine were determined in the medial prefrontal cortex and dorsal hippocampus of adult male Sprague-Dawley rats using dual probe in vivo microdialysis. Basal extracellular 5-HT did not differ between malnourished and well-nourished controls in either the medial prefrontal cortex or the dorsal hippocampus. Basal extracellular dopamine was significantly decreased in the medial prefrontal cortex of malnourished animals. Restraint stress (20 m) produced a significant rise in extracellular dopamine in the medial prefrontal cortex of well-nourished rats but did not alter release in malnourished rats. In malnourished rats, stress produced an increase in 5-HT in the hippocampus, whereas stress produced a decrease in 5-HT in the hippocampus of well-nourished rats. These data demonstrate that prenatal protein malnutrition alters dopaminergic neurotransmission in the medial prefrontal cortex as well as altering the dopaminergic and serotonergic response to stress. These changes may provide part of the bases for alterations in malnourished animals' response to stress.

Effects of Repeated Citalopram Treatments on Chronic Mild Stress-Induced Growth Associated Protein-43 mRNA Expression in Rat Hippocampus

“…In accordance with this result, there was a trend toward an increase of serotonin release in the hippocampus of CMS-exposed rats (Bekris et al, 2005) with some inconsistency (Kang et al, 2005). Although there are some controversies, with regard to acute stress, accumulating evidence has demonstrated that acute stress does not change or decrease serotonin release in the hippocampus (Kirby et al, 1995;Kirby et al, 1997;Mokler et al, 2007), further reinforcing the view that decreased serotonergic transmission in the hippocampus may lead to increased GAP-43 mRNA expression.…”

Poor pubertal protein nutrition disturbs glucose-induced insulin secretion process in pancreatic islets and programs rats in adulthood to increase fat accumulation

“…Hypothalamic neuron dense areas related to body weight (BW) control are changed in adult rats that were malnourished during pregnancy (Mokler et al 2007). Similar results were obtained in rats from dams that were protein restricted during gestation and lactation (Plagemann et al 2000a,b).…”

Prenatal Stress Exposure Increases the Excitation of Dopamine Neurons in the Ventral Tegmental Area and Alters Their Reponses to Psychostimulants

“…Reduced DA turnover in nucleus accumbens is reported in female rats with PSE, suggesting decreased DA release (Mastorci et al, 2009). Microdialysis studies find that PSE leads to an increase in both basal and amphetaminestimulated DA levels in nucleus accumbens (Silvagni et al, 2008), but a decrease (Mokler et al, 2007) or no changes (Carboni et al, 2010) in basal level of DA in the prefrontal cortex. The cause for these differences is not clear.…”