Increased dilator response to heptanol and octanol in aorta from DOCA-salt-hypertensive rats

This study tests the hypothesis that contractile responses in aortae of hyp ertensive rats are more dependent on gap junctional communication compared to those from normotensive rats. The experimental approach was pharmacologi cal, using inhibitors of gap junctional activity (heptanol and octanol). Tw o models of experimental hypertension were characterized: (1) mineralocorti coid (DOCA)-hypertensive rats and (2) stroke-prone spontaneous hypertensive rats (SHRSP), Vessels from DOCA-hypertensive rats showed a greater relaxat ion to heptanol and octanol, particularly when precontracted with phenyleph rine, compared to sham-operated animals. Octanol-induced relaxation in aort ic segments from SHRSP did not differ from normotensive values regardless o f the agonist used to cause contraction, These results suggest that in DOCA hypertension, gap junctional communication and voltage-operated calcium ch annels are differentially regulated, which could explain in part the change s in vascular reactivity observed in mineralocorticoid hypertension. Copyri ght (C) 2001 S. Karger AG, Basel.