We previously reported that paeoniflorin but not albiflorin, components of peony root, produced ameliorative effects on scopolamine-induced spatial cognitive impairment in rats. In this study, we examined the effects of paeoniflorin and muscarinic receptor antagonists on long-term potentiation (LTP) of population spike recorded from the CA1 region of rat hippocampal slices. Bath applications of an M1 and M2-receptor antagonist scopolamine and a selective M1-receptor antagonist pirenzepine, at a concentration of 10 μM, significantly suppressed LTP, whereas AF-DX116, a selective M2-receptor antagonist, failed to affect it. Paeoniflorin (0.1-1 μM), which alone was ineffective on LTP induction, significantly reversed the suppressive effects of scopolamine and pirenzepine (10 μM). In contrast, albiflorin (0.1-Ι μM) had no effect on the scopolamine-induced LTP suppression. These results suggest that paeoniflorin reversal of the muscarinic M1-receptor-mediated inhibition of LTP may be implicated in the ameliorative effect of paeoniflorin on spatial cognitive impairment caused by cholinergic dysfunction.
hippocampus, paeoniflorin, long-term potentiation (LTP), muscarinic M1-receptor, scopolamine
NCBI PubMed ID: 10887937Publication DOI: 10.1254/jjp.83.25Journal NLM ID: 2983305RPublisher: Japanese Pharmacological Society
Institutions: Department of Pharmacology, Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan
Methods: biological assays
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