title: PB-2, a polysaccharide fraction from lichen Flavoparmelia baltimorensis, peripherally promotes the induction of long-term potentiation in the rat dentate gyrus in vivo.
abstract: We have previously found that oral or intravenous administration of PC-2, a polysaccharide fraction purified from extracts of lichen Flavoparmelia caperata, facilitates the induction of long-term potentiation (LTP) in the dentate gyrus of anesthetized rats. PC-2 could be useful in the development of therapeutic drugs for senile dementia. However, it has been very difficult to obtain the material Flavoparmelia caperata because of its scarcity. In the present study, we therefore investigated whether PB-2, a polysaccharide fraction from another lichen Flavoparmelia baltimorensis, has similar biological effects. Oral administration of PB-2 (100-200 mg/kg) did not affect basal evoked potentials, but significantly promoted the induction of LTP following tetanic stimulation (30 pulses at 60 Hz) in the dentate gyrus of anesthetized rats. Intravenous injection of PB-2 (1-5 mg/kg) was also effective in promoting the induction of LTP, but intracerebroventricular injection of PB-2 (1-2 mg/brain) was ineffective. PB-2, as well as PC-2, should be valuable in identifying factors that promote synaptic plasticity in the hippocampus.
authors.affiliation: Department of Pharmacology, College of Pharmacy, Nihon University, 274-8555, Chiba, Japan.
authors.forename: Eiko
authors.initials: E
authors.lastname: Hirano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saito
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ito
authors.forename: Kumiko
authors.initials: K
authors.lastname: Ishige
authors.forename: Yoshikuni
authors.initials: Y
authors.lastname: Edagawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Shimizu
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Takeda
authors.forename: Takao
authors.initials: T
authors.lastname: Narui
authors.forename: Shoji
authors.initials: S
authors.lastname: Shibara
authors.forename: Kazuho
authors.initials: K
authors.lastname: Abe
mesh_terms: D000758:Anesthesia; D000818:Animals; D018891:Dentate Gyrus / Q000187:drug effects*; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004594:Electrophysiology; D005071:Evoked Potentials / Q000187:drug effects; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D008011:Lichens / Q000737:chemistry*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D011134:Polysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D014020:Tissue Extracts / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D011134:Polysaccharides; D014020:Tissue Extracts