Cardiovascular and autonomic effects of ω-conotoxins MVIIA and CVID in conscious rabbits and isolated tissue assays

Abstract

1. The effects of a novel N-type voltage-operated calcium channel antagonist, ω-conotoxin CVID, were compared with ω-conotoxin MVIIA on sympathetic-evoked activation of right atria (RA), small mesenteric arteries (MA) and vasa deferentia (VD) isolated from the rat. Their effects were also compared on blood pressure and cardiovascular reflexes in conscious rabbits. 2. The pIC50 values for MVIIA and CVID, respectively, for inhibiting sympathetic-evoked responses were equivalent in RA (8.7 and 8.7) and VD (9.0 and 8.7); however, in MA the values were 8.4 and 7.7. The cardiac to vascular (RA/MA) potency ratios, antilog (plog RA-plog MA), for MVIIA and CVID were 2 and 10. The offset rates for CVI..