Intracerebroventricular injection of neosurugatoxin induces a prolonged blockade of brain nicotinic acetylcholine receptors.

The intracerebroventricular injection of neosurugatoxin (2 x 3.2 micrograms) significantly reduced the specific binding of [3H]nicotine but not of [3H]cismethyldioxolane in the cerebral cortex, hippocampus and thalamus of rats 3 days after the toxin injection. Scatchard analysis of [3H]nicotine binding in the rat cerebral cortex revealed that neosurugatoxin can selectively decrease the maximal binding sites (Bmax) for [3H]nicotine by approximately 38%. A significant decrease in the Bmax value for [3H]nicotine was also observed in this brain region 7 days after the neosurugatoxin injection. Thus, the intracerebroventricular injection of neosurugatoxin can induce a prolonged blockade of brain nicotinic acetylcholine receptors.