Resveratrol's initial transient enhancement of adrenergic contractions of rat tail arterial tissues involves a mechanism limiting its ability to exert a later sustained relaxation

We have reported that resveratrol can enhance as well as relax adrenergic contractions of arterial tissue rings prepared from both proximal (conductance) and distal (resistance) segments of the long ventral tail artery of the rat (Stom, JSMR 2016; 52:18–35). While the enhancing action only occurred in approximately half of our ring preparations (from proximal and distal segments alike), it always appeared immediately after administration before the later, more sustained relaxing effect (which occurred in all preparations) became apparent. Thus, the enhancing effect seemed to be only transient in duration. However, that does not rule out the possibility of its mechanism lasting long enough to limit the degree to which resveratrol eventually causes relaxation. To determine if that were true, we re‐examined data from our original arterial ring preparations to see if the half in which early transient enhancement occurred showed less eventual relaxation compared to the half in which they did not occur. Indeed, that was the case. This provides a novel explanation for why long‐term administration of resveratrol in vivo is reported to lower arterial blood pressures in some clinical studies but not in others, as highlighted in recent reviews (e.g. Liu, Clin Nutr 2015; 34: 27–34). Support or Funding Information MWU Biomedical Masters Program