Depression-like behavioral and endocrine effects of brain glucocorticoid type I receptors in the male rat
Year: 1998
Type: dissertation
Abstract: Much evidence ties decreased brain glucocorticoid receptors together with anxiety and clinical depression.There are two known types of glucocorticoid receptors in the brain, type I (MR) and type II (GR).MR and GR often coexist in hippocampal and other limbic neurons and often cause different effects within these neurons, within the brain and in animal behavior.The present study examined the effects of chronic alterations in the stimulation of brain M R on depression associated behaviors using an open field test, circadian and 24-hour locomotor activity and plasma corticosterone (B).Rats were chronically exposed to an intracerebroventricular infusion of vehicle (propylene glycol), M R agonist (aldosterone) or MR antagonist (spironolactone) using ALZET mini-osmotic pumps.Two days following pump placement locomotor activity was monitored for 24 hours in all rats.Spironolactone decreased in total 24-hour activity from pre treatment control levels and all other treatments, (p<0.01).This effect was most pronounced during the dark phase of the light cycle.There was no difference between any of the treatment groups in plasma B concentration determined by RIA, nor inner nor outer squares entered in the open field test.Intracerebral infusions decreased open field activity, although this was not correlated with the treatment.MR were examined using a monoclonal antibody raised to the renal MR ligand-binding domain and GR were examined using a polyclonal antibody.GR were observed in both kidney and hippocampal tissues, MR were observed only in the kidney.This was true for both immunocytochemical and Western blot analysis.The results provide evidence that brain MR are linked to locomotor activity, and potentially depression.Furthermore, evidence was collected to suggest that hippocampal MR are different from renal MR.The spiritual realm governing my existence, thank you for the mercy, love, joy, wonderment, beauty, and protection in my life, and endurance of our relationship which, adjusts with my awareness, interpretation and enlightenment.
Source: The Mathematics Enthusiast
Author: Bret Fajans Bessac
Language: English
Subfield: Behavioral Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2474311326