Dual effects of the lichen glucan PB-2, extracted from Flavoparmelia baltimorensis, on the induction of long-term potentiation in the dentate gyrus of the anesthetized rat: possible mediation via adrenaline β- and interleukin-1 receptors
- 作者：Edagawa ; Yoshikuni ; Sato ; Fumiyuki ; Saito ; Hiroshi ; Takeda ; Tadahiro ; Shimizu ; Noriko ; Narui ; Takao ; et. al.
- 关键词：C ; Excitable membranes and synaptic transmission ; Long-term potentiation ; pharmacology ; Interleukin-1脙脙脙脙 ; Adrenaline 脙脙脙脙-receptor ; Lichen ; Polysaccharide ; Long-term potentiation ; Hippocampus
- 刊名：Brain Research
- 出版年：2005
- 期刊代码：8_00068993
- 类别：neu
- 出版时间：January 25, 2005
- 卷：1032
- 期：1-2
- 页码：183-192
- 文件大小：392 K
摘要
We have previously found that oral or intravenous (i.v.) administration of the polysaccharide fraction PB-2, extracted from the lichen Flavoparmelia baltimorensis, facilitated the induction of long-term potentiation (LTP) in the dentate gyrus (DG) in vivo. In this study, the mechanism underlying the effect of PB-2 on the induction of LTP was investigated in the DG of anesthetized rat focusing on the contribution of the interleukin-1 (IL-1) receptor and the adrenaline 脦脦-receptor. An i.v. injection of IL-1ra (10脦脦脦9 g/kg), an antagonist of the IL-1 receptor, had no effect on the basal response in the DG; however, this treatment augmented the enhancement of LTP induced by a single i.v. injection of PB-2 (10脦脦脦3 g/kg). This potentiating effect was also observed following intracerebroventricular (i.c.v.) injection of IL-1ra (10脦脦脦15脦脦脦10脦脦脦11 g). An i.v. injection of IL-1脦脦 (3.5脦脦10脦脦脦15脦脦脦3.5脦脦10脦脦脦9 g/kg) inhibited the induction of LTP, which was diminished by the previous application of IL-1ra. These results suggest that the activation of the IL-1 receptor induces the suppression of LTP in PB-2-treated rats, and that endogenous IL-1脦脦 contributes to the IL-1 receptor activation. An i.c.v. infusion of metoprolol (7.5 脦脦 10脦脦脦6 g), an antagonist of the adrenaline 脦脦1-receptor, attenuated the enhancement of LTP induced by an i.v. injection of PB-2. These results suggest that PB-2 has two different effects on the LTP, an enhancing effect and an inhibiting one, and that it exhibited the significant enhancing effect on the LTP as a total balance of these effects.