Earline Edwards

Learn More
Congenitally helpless rats have been selectively bred to display an immediate helpless response to stress in order to model hereditary brain differences that contribute to depression vulnerability. Differences in regional brain metabolism between congenitally helpless and non-helpless rats were investigated using quantitative cytochrome oxidase(More)
BACKGROUND Exposure to extremely stressful events can lead to Posttraumatic stress disorder (PTSD). Due to the complexity of PTSD, animal models have been designed and advanced to address the role of psychosocial stressors in the etiology; however, the apparent role of genetics in susceptibility to PTSD-like behaviors in animals remains unexplored. (More)
In this study, we examined the interaction of 5-HT1A and 5-HT2A receptors in the rat medial prefrontal cortex (mPFc) using the techniques of extracellular single unit recording and microiontophoresis. The iontophoresis of the selective 5-HT1A receptor agonist (+-)-8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT) produced a current-dependent suppression(More)
Serotonin (5-hydroxytryptamine, 5-HT) and various tryptamine-related drugs were equi-potent to known beta-antagonists in competition experiments of 125Iodo-cyanopindolol binding in the rat hippocampus. IC50 values for all the tryptamine related drugs (5,7-DHT, 5-MT, 5-MEO, DMT) were very similar to those obtained for (-)-propranolol, (+/-)-cyanopindolol,(More)
In the present study, we investigated the effects of various serotonin (5-HT) antagonists on 5-HT's action on medial prefrontal cortical cells (mPFc) using the techniques of single cell recording and microiontophoresis. The microiontophoretic application of 5-HT (10-80 nA) produced a current-dependent suppression of mPFc cell firing and this effect was(More)
After exposure to a 0.8 mA course of uncontrollable shocks, Sprague-Dawley rats can be differentiated into two distinct groups defined in term of their performance in a shock escape paradigm. Learned helpless (LH) rats do not learn to escape a controllable shock while non-helpless (NLH) rats learn this response as quickly as naive controls (NC) rats do. The(More)
The present experiments examined the role of the serotonergic system in the behavioral deficit produced by uncontrollable shock. In Experiment 1: Establishment of model, the behavioral potential of the Sprague-Dawley rat was defined. When exposed to mild uncontrollable stress such as a 0.8 mA electric footshock, a significant percentage of rats developed a(More)
Early in the development of the hypothalamic-pituitary-adrenal (HPA) axis, the rat undergoes a stress hyporesponsive period of blunted responses to several stressors including cold exposure (CE) and maternal deprivation (MD). We examined the development of the axis by monitoring adrenocorticotropin hormone (ACTH) plasma levels in an animal model of(More)
This study examines the effect of intraventricular administration of the neurotoxin 5,7-dihydroxytryptamine on serotonin1A, serotonin2 and serotonin3 receptors in the rat medial prefrontal cortex using in vivo extracellular single cell recording and iontophoresis. Iontophoresis of the serotonin1A, serotonin1C,2 and serotonin3 receptor agonists(More)
The induction of learned helpless (LH) behavior in rats is a widely used model of unipolar depression. Recent studies have linked depression with hypertension and insulin resistance as observed in obesity, but the propensity of these disorders to manifest depression has not been reported. In this study, the LH behavioral paradigm was exploited in a model of(More)