Effects
of PACAP, VIP and their peptide fragments on scopolamine-induced
impaired performance and on the ChAT activity in the brain of
rats
by
Yoshimasa Yamaguchi, Masaya Higashi, Masahiro Nishio and Hidcshi
Kobayashi
Research Laboratory, Zenyaku Kogyo Co., Ltd, 2-33-7, Ohizumi-machi,
Nerima-ku, Tokyo 178, Japan
Received February 24. 1997
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP1-27),
a member of the vasoactive intestinal peptide (VIP) family,
VIP1-28, VIP10-28 and VIP1-12 were examined to determine whether
they have ameliorative effects on impaired performance caused
by scopolamine in a radial-arm maze in rats. In addition, the
N-terminal three-amino acid sequence (VIP1-3) shared by PACAP
and VIP was tested. Single intraperitoneal (i.p.) injections
of PACAP1-27, VIP1-28, VIP1-12 and VIP1-3 and showed ameliorative
effects on impaired performance, whereas VIP10-28 did not. The
N-terminal three-amino acid sequence was essential for the ameliorative
effects. PACAP1-27, VIP1-28, VIP1-12 and VIP1-3, but not VIP10-28,
caused increases in the ChAT activity in the medial septum,
but not in the diagonal band, caudate and hippocampus. The increase
in the ChAT activity produced by VIP, PACAP and their peptide
fragments in the medial septum is discussed in relation to their
ameliorative effects on scopolamine-induced spatial cognitive
impairment.
