to the morris water maze procedure morris et al nature 297 681 683 1982 morris et al nature 319 774 776 1986 rats were placed in a circular pool 1 26 m in diameter 0 2 m deep equipped with a clear plexiglas column with a 13 3 cm platform reaching just below the surface of the water 22 24 u00b0 c drugs were applied daily by nasal administration 1 hour prior to testing the latency of reaching the platform was recorded for each rat in seconds and the changes over days of training were graphed which reflect learning and memory as can be seen in fig2 control animals injected with af64a u25ef showed a smaller improvement in the latency of reaching the platforms compared with animals injected with af64a and nasally administered with st lys lys tyr leu nh 2 seq id no 6 ue8a0 these results indicate that the conjugate of the invention is able to improve learning and memory in an animal model of alzheimer fig3 depicts the effects of st lys lys tyr d ala nh 2 indicated kkyo in the figure on learning and memory in the alzheimer 39 s in vivo test af64a cholinotoxicity test as described above the results obtained were similar to those described above with control animals which were treated only with af64a ue8a0 showed smaller improvement in the latency of reaching the platforms compared with animals nasally administered also with st lys lys tyr d ala nh 2 u25b4 an additional probe test was also performed gozes et al proc nat acad sci usa 93 427 432 1996 in this test after the animals know.