Changes in blood pressure in the rat induced by the venom extract from a sea anemone-Bunodosoma cavernata

The effect of graded doses of crude sea anemone extract from Bunodosoma cavernata on rat blood pressure was investigated with a view to accessing its effects on the status of the cardiovascular system. From the results, the extract (2-8 ug protein/kg, i.v.) caused only transient hypotension. With higher doses of the extract (10-20 ug protein/kg, i.v.), the transient hypotension was accompanied by a dose-dependent increase in blood pressure. Atropine, mepyramine and propranolol failed to affect the transient hypotension. Of these drugs, only propranolol decreased the extract-induced hypertension. Doses of the extract above 20 ug protein/kg, i.v. produced a decrease in pulse rate and an increase in pulse pressure. We suggest that the extract-induced transient hypotension could be due to the presence of a less potent agent in the extract with acetylcholine-like action, and the hypertensive action of the extract was probably due to the stimulation of the sympathetic division of the autonomic nervous system by agent(s) in the extract.