Aging differentially modifies sensitivity of nerve blood flow to vasocontractile agents (endothelin-1, noradrenaline and angiotensin II) in sciatic nerve.

This study examined the influence of the vaso-constricting agents (noradrenaline, endothelin-1 and angiotensin II) in Sprague-Dawley rats aged 2, 6 and 24 months by evaluating epineurial arteriolar vasoreactivity in response to superfused teat agents. Nerve blood flow (NBF) was measured using microelectrode H2 polarography. In 24-month-old rats, NBF was decreased and vascular resistance (VR) was increased compared with 2- and 6-month-old rats. All of the constricting agents reduced NBF in the 2-, 6- and 24-month groups, however, the effects of the constricting agents reduced significantly with age. These results suggest that during aging, there is a decline of vasoconstrictive responses to noradrenaline, endothelin-1 and angiotensin II in peripheral nerve and that these changes may be due to altered function of receptors.