Stimulation of muscarinic receptor in hippocampal neuron induces characteristic increase in cytosolic free Ca2+ concentration.
Changes in cytosolic free Ca2+ concentration ([Ca2+]i) in response to acetylcholine (ACh) were examined by fura-2 fluorometry in cultured rat hippocampal neurons. ACh (greater than or equal to 10(-5) M) induced an increase in [Ca2+]i composed of fast transient and slow long-lasting phases. Atropine (10(-8) M) abolished the fast component and greatly reduced the slow component. The slow component was selectively blocked by pirenzepine (10(-6) M). The effect of ACh remained partially in a Ca2+-deficient medium where effects of L-glutamate and KCl (50 mM) were abolished. Present results suggest that ACh elevates [Ca2+]i by activation of muscarinic receptor subtypes, one of which is coupled with ion channels and the other of which transduces the ACh binding to mobilization of intracellularly stored Ca2+.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010890:Pirenzepine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin; D013997:Time Factors
D005971:Glutamates; D011976:Receptors, Muscarinic; D010890:Pirenzepine; D018698:Glutamic Acid; D013779:Tetrodotoxin; D001285:Atropine; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium