Modulation of long-term potentiation by individual subtypes of muscarinic acetylcholine receptor in the rat dentate gyrus.
The roles of the muscarinic acetylcholine (ACh) receptors (mAChRs) in long-term potentiation (LTP) at many areas of the central nervous system including the hippocampus, have been extensively studied. However, not much is known about the modulation of LTP through individual subtypes of mAChR (M(1)-M(5) subtype). In this study, we investigated the involvement of each individual subtypes of mAChR in LTP induction by intrahippocampal administration of cholinergic ligands at the dentate gyrus (DG) of anesthetized rats. We found atropine, an antagonist of mAChRs, suppressed the induction of LTP. This observation confirmed that the muscarinic system is involved in LTP. We then examined the effects of M(1)AChR antagonists (pirenzepine and telenzepine), M(2/4)AChR antagonists (Methoctramine and {11-[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one}(AFDX-116)), and M(3/5)AChR antagonist (4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP)) on LTP. Our results showed that both M(1)AChR and M(2/4)AChR antagonists but not M(3/5)AChR antagonist suppressed the amplitude of LTP. We also examined the effects of these cholinergic ligands on basal synaptic transmission and found that only pirenzepine augmented the amplitude of population spike. This study suggests that individual mAChR subtypes play different modulation roles in LTP induction in the DG of rats.
Luo
Le
L
School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China 230027.
Chen
Wei-Heng
WH
Wang
Ming
M
Zhu
Da-Miao
DM
She
Jia-Qi
JQ
Ruan
Di-Yun
DY
D000818:Animals; D018891:Dentate Gyrus / Q000187:drug effects / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005260:Female; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic