THE EFFECTS OF CENTRAL ADMINISTRATION OF ω‐CONOTOXIN GVIA ON CARDIOVASCULAR PARAMETERS AND AUTONOMIC REFLEXES IN CONSCIOUS RABBITS

Abstract

1. The effects of central administration of ω‐conotoxin GVIA (ω‐CTX), an N‐type calcium channel blocker, were examined in conscious rabbits implanted with lateral intracerebroventricular (i.c.v.) cannulae. 2. Experiments were performed over 4 consecutive days. On day 1, the baroreceptor heart rate (induced by glyceryl trinitrate and phenylephrine) and Bezold‐Jarisch like (elicited by serotonin) reflexes were measured before (0 h) and 2 h after central administration of ω‐CTX (3 or 30 pmol/ kg, i.c.v.) or vehicle. On days 2–4, resting parameters and reflexes were again monitored but no further ω‐CTX was administered. 3. No change in heart rate (HR) was observed in any rabbit treatment group d..