The possibility that norepinephrine (NE) influences lymphoid cell outflow independently of its vasoconstrictor action was investigated in the perfused rat spleen. Using agents that affect the vasoconstrictor tonus of the spleen, we observed an inverse correlation between flow resistance and splenic cell output. The curve obtained served as a reference for evaluating effects of different treatments on the number of cells that are mobilized at defined levels of flow resistance. Perfusion of the -adrenergic blocker propranolol either alone or in combination with NE lowered splenic leukocyte outflow clearly beyond the number of cells expected at the corresponding flow resistance. No comparable effects were observed when the -adrenergic blocker phentolamine was perfused. When the vasoconstrictor effect of NE was counteracted by papaverine, splenic cell outflow was significantly higher than expected for the level of flow resistance attained. Furthermore, when NE was perfused together with endotoxin, which does not inhibit the vasoconstriction induced by catecholamines, splenic cell mobilization was severalfold higher than expected at increased flow resistance. Propranolol abrogated this effect to a large extent. Furthermore, perfusion of the -agonist isoproterenol stimulated lymphoid cell outflow from the spleen despite increased flow resistance. These studies show a dual effect of NE on cell mobilization from the spleen: cell retention by decreasing blood flow and stimulation of cell output by a -adrenergically mediated, smooth muscle-independent mechanism.

lymphoid cell traffic; sympathetic nerves; endotoxin

This article has been cited by other articles:

				H. Rogausch, D. Zwingmann, M. Trudewind, A. del Rey, K.-H. Voigt, and H. Besedovsky Local and systemic autonomic nervous effects on cell migration to the spleen J Appl Physiol, February 1, 2003; 94(2): 469 - 475. [Abstract] [Full Text] [PDF]

				A. P. Kohm and V. M. Sanders Norepinephrine and beta 2-Adrenergic Receptor Stimulation Regulate CD4+ T and B Lymphocyte Function in Vitro and in Vivo Pharmacol. Rev., December 1, 2001; 53(4): 487 - 525. [Abstract] [Full Text] [PDF]

				G. J. M. Maestroni Dendritic Cell Migration Controlled by {alpha}1b-Adrenergic Receptors J. Immunol., December 15, 2000; 165(12): 6743 - 6747. [Abstract] [Full Text] [PDF]