We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Differential vasomotor effects of insulin on gastrocnemius and soleus feed arteries in the OLETF rat model: role of endothelin-1.
- Authors
Jenkins, Nathan T.; Padilla, Jaume; Martin, Jeffrey S.; Crissey, Jacqueline M.; Thyfault, John P.; Rector, R. Scott; Laughlin, M. Harold
- Abstract
New findings What is the central question of this study? This study investigated the influence of obesity on insulin-induced vasomotor reactivity in rat skeletal muscle feed arteries., What is the main finding and its importance? Irrespective of obesity, the gastrocnemius feed artery displayed diminished insulin-induced vasodilatory response compared to the soleus feed artery. This difference between the arteries was abolished in the presence of an endothelin-1 receptor antagonist. Therefore, our findings demonstrate that insulin-induced endothelin-1 production is not uniform among all skeletal muscle resistance vessels., The vascular actions of insulin are complex, because it can stimulate both nitric oxide-mediated dilatation and endothelin (ET)-1-mediated constriction. We examined vasoreactivity to insulin in isolated feed arteries of the gastrocnemius (GFA) and soleus muscles (SFA) of 32-week-old Long-Evans Tokushima Otsuka (LETO) and Otsuka Long-Evans Tokushima fatty (OLETF) rats, a hyperphagic rodent model of obesity and insulin resistance. The insulin-induced vasoreactivity of SFA and GFA was similar in LETO (healthy) and OLETF (obese/insulin-resistant) rats. However, examination of between-vessel effects revealed a number of novel insights into the heterogeneous vascular effects of insulin. Soleus feed arteries dilated more than GFA in LETO at 100 and 1000 μIU ml−1 insulin (23 versus 6 and 28 versus 0%, respectively; P < 0.05 for between-vessel differences). Likewise, in OLETF rats there was significantly greater dilatation in SFA than GFA at 10, 100 and 1000 μIU ml−1 insulin (28 versus 3, 30 versus 0 and 34 versus 0%, respectively; all P < 0.05). In the presence of 3 μ m tezosentan, a non-specific endothelin-1 receptor blocker, insulin-induced dilatation of the GFA was enhanced such that differences between vessels were largely abolished in both groups. Furthermore, acetylecholine-induced dilatation was significantly greater in SFA than GFA within each group, whereas sodium nitroprusside-induced dilatory responses were greater in the GFA compared with the SFA. Overall, our findings indicate that the insulin/endothelin-1 vasoconstrictor pathway is more active in GFA than in SFA, independent of obesity in the OLETF rat model.
- Subjects
OBESITY; INSULIN; SKELETAL muscle; ENDOTHELINS; VASOMOTOR conditioning
- Publication
Experimental Physiology, 2014, Vol 99, Issue 1, p262
- ISSN
0958-0670
- Publication type
Article
- DOI
10.1113/expphysiol.2013.074047