Peripheral injection of dexamethasone modulates anxiety related behaviors in mice: an interaction with opioidergic neurons.
Stress and anxiety initiates a cascade of biochemical and endocrine event which results in behavioral and electrophysiological effects in both animals and humans. In this study, we investigated the effects of dexamethasone (DEX), as a synthetic glucocorticoid, and its interaction with opioidergic system on anxiety related behavior in mice. Young adult male mice were used in this study. A standard elevated plus-maze was used to determine anxiety levels in animal. Different doses of DEX (0.1, 0.5, 1, 2 and 10 mg/kg, SC) or vehicle was injected 30 min before of evaluation. Naloxone (1 and 2 mg/kg, IP) was injected 5 min before the DEX (0.5 and 1 mg/kg) administration. Results indicated that DEX at doses of 0.5 and 1 reduced and in dose of 10 mg/kg increased anxiety related behaviors significantly (P<0.05 in all cases). Also pretreatment of naloxone at doses of 1 and 2 mg/kg attenuated the effects of lower doses of DEX on anxiety related behaviors. Finding above indicated that peripheral administration of glucocorticoids induces biphasic effects on anxiety related behaviors: anxiolytic effects in lower doses and anxiogenic effects in a high dose. Data also revealed an involvement of opioidergic system in anxiolytic effects of glucocorticoids.
Vafaei
Abbas Ali
AA
Physiology Research Center, Semnan University of Medical Sciences, Semnan, Iran. aavaf43@yahoo.com
Rashidy-Pour
Ali
A
Taherian
Abbas Ali
AA
D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001007:Anxiety / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control* / Q000523:psychology; D001522:Behavior, Animal / Q000187:drug effects*; D003907:Dexamethasone / Q000008:administration & dosage* / Q000009:adverse effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000009:adverse effects; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018847:Opioid Peptides / Q000378:metabolism; D011957:Receptors, Opioid / Q000378:metabolism
D014151:Anti-Anxiety Agents; D005938:Glucocorticoids; D009292:Narcotic Antagonists; D018847:Opioid Peptides; D011957:Receptors, Opioid; D009270:Naloxone; D003907:Dexamethasone