Dopamine D1 and D2 dopamine receptors regulate immobilization stress-induced activation of the hypothalamus-pituitary-adrenal axis.
BACKGROUND
Whereas the role of most biogenic amines in the control of the hypothalamus-pituitary-adrenal (HPA) response to stress has been extensively studied, the role of dopamine has not.


OBJECTIVE
We studied the effect of different dopamine receptor antagonists on HPA response to a severe stressor (immobilization, IMO) in adult male Sprague-Dawley rats.


RESULTS
Haloperidol administration reduced adrenocorticotropin hormone and corticosterone responses to acute IMO, particularly during the post-IMO period. This effect cannot be explained by a role of dopamine to maintain a sustained activation of the HPA axis as haloperidol did not modify the response to prolonged (up to 6 h) IMO. Administration of more selective D1 and D2 receptor antagonists (SCH23390 and eticlopride, respectively) also resulted in lower and/or shorter lasting HPA response to IMO.


CONCLUSIONS
Dopamine, acting through both D1 and D2 receptors, exerts a stimulatory role on the activation of the HPA axis in response to a severe stressor. The finding that dopamine is involved in the maintenance of post-stress activation of the HPA axis is potentially important because the actual pathological impact of HPA activation is likely to be related to the area under the curve of plasma glucocorticoid levels, which is critically dependent on how long after stress high levels of glucocorticoid are maintained.
Belda
Xavier
X
Institut de Neurociències and Unitat de Fisiologia Animal (Facultat de Biociències), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Armario
Antonio
A
D000818:Animals; D019540:Area Under Curve; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D005938:Glucocorticoids / Q000097:blood; D006220:Haloperidol / Q000494:pharmacology; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D008297:Male; D010913:Pituitary-Adrenal System / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D012149:Restraint, Physical / Q000523:psychology; D013315:Stress, Psychological / Q000378:metabolism*
D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D005938:Glucocorticoids; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D006220:Haloperidol; D004298:Dopamine