Concurrent blockade of beta-adrenergic and muscarinic receptors suppresses synergistically long-term potentiation of population spikes in the rat hippocampal CA1 region.
The muscarinic acetylcholine receptor antagonist scopolamine, but not the beta-adrenoceptor antagonist propranolol or atenolol, suppressed tetanus-induced long-term potentiation (LTP) of population spikes in the rat hippocampal CA1 region. When scopolamine was coapplied with propranolol or atenolol, a synergistic effect in preventing LTP generation was observed. On the other hand, the coapplication of scopolamine and atenolol failed to affect tetanus-induced LTP of field EPSP. These findings suggest that cooperative mechanisms via muscarinic and beta-adrenergic receptor activation might contribute to LTP induction in terms of the EPSP-spike potentiation, i.e., an increase in the excitability of hippocampal CA1 pyramidal cells after tetanic stimulation, but are independent of the tetanus-evoked potentiation of a synaptic component.
Kobayashi
M
M
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Ohno
M
M
Shibata
S
S
Yamamoto
T
T
Watanabe
S
S
D000109:Acetylcholine / Q000502:physiology; D000200:Action Potentials / Q000187:drug effects; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D006624:Hippocampus / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D009638:Norepinephrine / Q000502:physiology; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000502:physiology; D012601:Scopolamine / Q000494:pharmacology*
D000319:Adrenergic beta-Antagonists; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D001262:Atenolol; D011433:Propranolol; D012601:Scopolamine; D000109:Acetylcholine; D009638:Norepinephrine