vasomotor
    adj 1: relating to the nerves and muscles that cause the blood
           vessels to constrict or dilate

Vasomotor \Vas`o*mo"tor\, a. [L. vas a vessel + motor that which
   moves fr. movere to move.] (Physiol.)
   Causing movement in the walls of vessels; as, the vasomotor
   mechanisms; the vasomotor nerves, a system of nerves
   distributed over the muscular coats of the blood vessels.
   [1913 Webster]

   Vasomotor center, the chief dominating or general center
      which supplies all the unstriped muscles of the arterial
      system with motor nerves, situated in a part of the
      medulla oblongata; a center of reflex action by the
      working of which afferent impulses are changed into
      efferent, -- vasomotor impulses leading either to dilation
      or constriction of the blood vessels.
      [1913 Webster]