Phosphoinositides and GTP binding proteins involved in muscarinic generation of hippocampal rhythmic slow activity.
We examined the role of phosphoinositide turnover in muscarinic rhythmic slow activity (RSA; also called theta) in rat CA3 pyramidal neurons. Pre-incubation of hippocampal slices in pertussis toxin (which inhibits some GTP-binding proteins) or in Li+ (which blocks inositol phosphate degradation, and thereby decreases the resynthesis of phosphoinositides), prevented the induction of RSA by carbachol. Phorbol esters, which can activate protein kinase C (PKC) directly, did not induce RSA but inhibited muscarinic RSA. We infer that muscarinic RSA involves a GTP-binding protein linked increase in phosphoinositide turnover, while the activation of PKC may have a negative feedback role.
Tse
F W
FW
Neuroscience Research Group, University of Calgary, Alta, Canada.
MacVicar
B A
BA
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D066298:In Vitro Techniques; D010716:Phosphatidylinositols / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
D010716:Phosphatidylinositols; D011976:Receptors, Muscarinic; D002217:Carbachol; D019204:GTP-Binding Proteins