EFFECTS OF ISOVANIHUPERZINE-A ON CHOLINES TERASE AND SCOPOLAMINE-INDUCED MEMORY IMPAIRMENT

AIM: To study the effects of isovanihuperzine A (IVHA) on cholinestera se and scopolamine-induced memory deficit. METHODS: AChE and BuChE act ivities were determined by the colorimetric method of Ellman. The K-i value was determined by the plotting method of Lineweaver and Burk. In a behavioral test, rats were trained to perform a radial arm maze tas k using a partially baited procedure. RESULTS: The anti-AChE activity of IVHA was comparable to huperzine A (Hup-A), and was more potent tha n those of physostigmine and galanthamine with an IC50 value of 0. 11 mu mol . L(-1). IVHA was a mixed competitive type with a K-i value of 32 nmol . L(-1). It bound to AChE in a reversible man ner. IVHA at a d ose of 0. 2 mg . kg(-1) ip significantly reversed scopolamine-induced working memory and reference memory impairments in radial arm maze. CO NCLUSION: IVHA is a new potential reversible AChE inhibitor and merits further study as a cognitive enhancer.