Effect of crowding on corticosterone responses to central adrenergic stimulation.
The social stress of crowding for 3, 7 and 14 days considerably reduced the increase in serum corticosterone elicited by intracerebroventricular administration of isoprenaline, a beta-adrenergic agonist, on the 3rd and 7th days of crowding. The corticosterone response to clonidine, an alpha 2-adrenergic agonist, was significantly diminished only after 3 days of crowding and this reduction was paralleled by a significant decrease in hypothalamic histamine content. The stimulatory effect of phenylephrine, an alpha 1-adrenergic agonist, was not significantly changed by crowding stress. Social crowding stress caused almost total and persistent reduction in the hypothalamic-pituitary-adrenocortical (HPA) responsiveness to noradrenaline which stimulates the HPA axis via both alpha- and beta-adrenergic receptors.
Bugajski
J
J
Institute of Pharmacology, Polish Academy of Sciences, Kraków.
Gadek-Michalska
A
A
Borycz
J
J
Wieczorek
E
E
D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D003345:Corticosterone / Q000097:blood*; D003441:Crowding / Q000503:physiopathology*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology*; D007276:Injections, Intraventricular; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011941:Receptors, Adrenergic / Q000502:physiology*; D013315:Stress, Psychological / Q000097:blood*
D011941:Receptors, Adrenergic; D010656:Phenylephrine; D007545:Isoproterenol; D003000:Clonidine; D003345:Corticosterone; D009638:Norepinephrine