Continuous in vivo treatment with catecholamines suppresses in vitro reactivity of rat peripheral blood T-lymphocytes via alpha-mediated mechanisms.
A 20 h continuous treatment of rats with catecholamines, using subcutaneously implantable retard tablets, had either no (adrenaline, isoproterenol, midodrine) or a slight (noradrenaline) suppressive effect on the in vitro responsiveness of peripheral blood T-lymphocytes. A marked suppression of the mitogen response ensued when adrenaline, noradrenaline or midodrine, but not isoproterenol, was applied together with the beta-receptor blocker propranolol, whereas the combination with the alpha-receptor blocker phentolamine had no effect. The mitogen response of splenic lymphocytes was not affected by any of these treatments. This alpha-mediated adrenergic suppression of peripheral blood T-cells was not correlated with general metabolic alterations, shifts in white blood cell counts or CD4+/CD8+ subsets, or with elevated glucocorticoid levels. The data suggest that to consistently influence the reactivity of rat peripheral blood lymphocytes by chronic adrenergic stimuli in vivo requires both high catecholamine levels and a bias towards alpha-adrenergic receptivity.
Department of Functional Pathology, School of Medicine, University of Graz, Austria.
P
P
Felsner
D
D
Hofer
I
I
Rinner
H
H
Mangge
M
M
Gruber
W
W
Korsatko
K
K
Schauenstein
D000818:Animals; D001773:Blood Cells / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004837:Epinephrine / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology; D007958:Leukocyte Count / Q000187:drug effects; D016131:Lymphocyte Subsets / Q000187:drug effects; D008297:Male; D008879:Midodrine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D013312:Stress, Physiological / Q000097:blood; D013566:Sympathomimetics / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000502:physiology*
D011942:Receptors, Adrenergic, alpha; D013566:Sympathomimetics; D008879:Midodrine; D011433:Propranolol; D007545:Isoproterenol; D003345:Corticosterone; D009638:Norepinephrine; D004837:Epinephrine