Cardiac noradrenaline in experimental rat envenomation with Africanized bee venom

The concentration of cardiac tissue noradrenaline (NOR) was determined in Wistar rats injected with 1.5 microliters/100 g body weight Africanized bee venom (ABV) (LD50 = 0.8 microliter/100 g body weight by the intravenous route). The animals were injected with ABV by the intramuscular (IM), intraperitoneal (IP), subcutaneous (SC) and intravenous (IV) routes. Animals injected by the IM, IP and SC routes were sacrificed 4, 7 and 24 hours after injection. The animals injected by the IV route were sacrificed when they became apnoeic (within minutes). NOR levels in animals injected by the IM, IP and SC routes were inconstant and inconclusive. In contrast, animals injected with ABV by the IV route showed a significant decrease in NOR concentration when compared to their respective controls, suggesting tissue NOR release. It is suggested that the mechanism of death of the animals injected IV with ABV seems to be related, at least in part, to functional cardiac alterations secondary to stress-induced NOR release. As a consequence, cardiological monitoring of patients who are victims of multiple bee stings is recommended, together with a judicious evaluation of therapy involving drugs with a sympathomimetic action.