title: Effects of arginine-vasopressin fragment 4-9 on rodent cholinergic systems.
abstract: Arginine-vasopressin fragment 4-9 (AVP4-9) has been demonstrated in animal studies to facilitate learning and memory. To clarify the mechanisms of this facilitation, we focused on the effects of AVP4-9 on rodent cholinergic systems. AVP4-9 (0.1 microM) enhanced the basal and the high-potassium-evoked acetylcholine (ACh) release from rat hippocampal slices (122.4 and 120.0% of control, respectively) in the presence of 1.3 mM calcium (physiological level) at 60 min after the incubation at 37 degrees C. The AVP4-9-stimulated basal ACh release was inhibited by a V1-selective antagonist ([(beta-mercapto-beta,beta-cyclopentamethylene propionic acid)1, O-methyl-Tyr2, Arg8] vasopressin), but not by a V2-selective antagonist ([adamantaneacetyl1, O-ethyl-D-Tyr2, Val4, aminobutyryl6, Arg8,9]-vasopressin). In addition, AVP4-9 did not affect the basal ACh release under the calcium-free condition at 37 degrees C or in the presence of 1.3 mM calcium at 4 degrees C. However, AVP4-9 facilitated the passive-avoidance response of scopolamine (a cholinergic blocker)-induced memory-deficient mice. These findings demonstrate that AVP4-9 stimulates ACh release via mediation by V1-like vasopressin receptors, and shows dependence on calcium ion and temperature. The results also suggest that the mechanism of the facilitative effects of AVP4-9 on learning and memory consist of the observed stimulation of cholinergic systems and other parallel pathways that would not be inhibited by cholinergic blocking.
authors.affiliation: Yakult Central Institute for Microbiological Research, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tanabe
authors.forename: Y
authors.initials: Y
authors.lastname: Shishido
authors.forename: Y
authors.initials: Y
authors.lastname: Nakayama
authors.forename: M
authors.initials: M
authors.lastname: Furushiro
authors.forename: S
authors.initials: S
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Terasaki
authors.forename: G
authors.initials: G
authors.lastname: Tsujimoto
authors.forename: T
authors.initials: T
authors.lastname: Yokokura
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007858:Learning / Q000187:drug effects*; D008297:Male; D008568:Memory / Q000187:drug effects*; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012601:Scopolamine / Q000494:pharmacology; D013696:Temperature
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D018727:Muscarinic Antagonists; D010446:Peptide Fragments; D001127:Arginine Vasopressin; C045881:argipressin (4-9); D012601:Scopolamine; D000109:Acetylcholine; D002118:Calcium