Classification of muscarinic responses in hippocampus in terms of receptor subtypes and second-messenger systems: electrophysiological studies in vitro

摘要: The hippocampal slice preparation was used to classify cholinergic effects in terms of muscarinic receptor subtypes (M1 or M2) and biochemical effector systems linked these CA1 pyramidal cells. Based on the action M1 antagonist pirenzepine M2 gallamine, muscarinic-induced membrane depolarization blockade afterhyperpolarization appear result from activation an receptor, while depression EPSP a potassium current termed M-current appears involve receptor. All actions could be observed pertussis toxin-treated hippocampi, suggesting that toxin-sensitive G-protein is not involved actions. Cholinergic agents are weak agonists phosphoinositide (PI) turnover fully effective all except which they had little agonist activity actually blocked full agonists. These results strongly suggest may stimulation PI turnover. In addition, we show mimicked by intracellular application inositol trisphosphate. Our do any obvious relationship between systems.