RECEPTIVE PROPERTIES OF AFFERENT NERVE-FIBERS ASSOCIATED WITH THE RATSAPHENOUS-VEIN

We tested afferent fibres isolated from the saphenous nerve for their responses to mechanical, osmotic and chemical stimuli applied to a vas cularly isolated segment of the saphenous vein in the rat. Fifteen uni ts were excited by local mechanical stimulation and many of them were also activated by distension of the venous segment, however exclusivel y by presumably noxious pressures. Most mechanosensitive fibres were e xcited by one of the three pain-producing substances, hyperosmotic sal ine (HS), potassium chloride (KCl) and bradykinin. Three fibres which were insensitive to mechanical stimulation, responded to injection of HS or KCI into the venous segment. We conclude that the venous afferen ts most likely have nociceptive function. Most are considered to be po lymodal.