Emotional stress evoked by immobilization of the rat induces c-fos mRNA or
other immediate early genes. This response is mediated by activation of alp
ha- and beta -adrenoceptors, through mechanisms that have not yet been eluc
idated. Here we show that immobilization stress activates p44/p42 Mitogen-A
ctivated Protein kinase (p44/p42 MAP kinase, Erk1/Erk2). Pretreatment with
the beta1-blocker, metoprolol, did not inhibit the activation of stress-ind
uced MAP kinase, while blockage of the al-adrenoceptor by pretreatment with
alpha1-blocker, prazosin or the alpha/beta -blocker, amosulalol, attenuate
d the activation. Application of the alpha1-agonist, phenylephrine, but not
the beta -agonist, isoproterenol, to the perfused rat heart elicited MAP a
ctivation. Thus, emotional stress activates the al-adrenoceptor-mediated MA
P kinase pathway, whereas the pathway of the response mediated by the beta
-adrenoceptor remains unknown. (C) 2001 Elsevier Science Inc. All rights re
served.