A Negative Inotropic Effect of Omega-Conotoxin GVIA in Isolated, Blood-Perfused Dog Right Atria.

Abstract

ABSTRACT-Using an isolated, blood-perfused canine atrial preparation, we investi gated the effects of omega-conotoxin GVIA (omega-CgTX), a blocker of N-type voltage-operated calcium channels, on the atrial contractile force and sinus rate. Omega-CgTX in a dose range of 0.3 3 nmol gradually attenuated the atrial contrac tile force in a dose-dependent manner, but did not affect the sinus rate, indicating that it can depress contractility but not pacemaker activity.