title: Effect of acute footshock stress on the responsiveness of the isolated rat tail artery to phenylephrine and epinephrine.
abstract: The effects of acute footshock stress on the sensitivity of the isolated rat tail artery were studied. Footshock stress applied to male Wistar rats (200-300 g) causes subsensitivity to the vasoconstrictor effects of phenylephrine and epinephrine. No significant changes in the pA2 values of prazosin were detected, using epinephrine as the agonist. Footshock stress-induced subsensitivity to epinephrine was not affected by the calcium entry blocker nifedipine. However, nifedipine significantly depressed the maximum response to epinephrine in tail arteries isolated from acute footshock-stressed rats. The present results suggest that acute footshock stress-induced reduced sensitivity to phenylephrine and epinephrine may not be only related to events at the alpha-adrenoceptor level. The nifedipine-induced depression of the maximum response to epinephrine suggests a role for the calcium mobilization processes in the vascular responsiveness during acute stress.
authors.affiliation: Departamento de Educação Fisica, Universidade Estadual de São Paulo, Rio Claro, Brasil.
authors.forename: A
authors.initials: A
authors.lastname: Zanesco
authors.forename: S
authors.initials: S
authors.lastname: De-Moraes
mesh_terms: D000818:Animals; D001158:Arteries / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology*; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D012680:Sensitivity and Specificity; D013312:Stress, Physiological; D013623:Tail / Q000098:blood supply*
chemical_list: D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D004837:Epinephrine