Septohippocampal cholinergic changes after destruction of the A10-septal dopaminergic pathways.
Mice were injected bilaterally into the septum with 6-hydroxydopamine and 6 weeks later the hippocampi were assayed for activity of choline acetyltransferase, muscarinic receptor binding capabilities and for formation of inositol phosphate in response to direct (carbachol) or presynaptically elicited (K+) stimulation of the postsynaptic receptors. Levels of dopamine in the septum were reduced by 70% in the lesioned animals and hippocampal choline acetyltransferase was elevated by the same amount. The Bmax of muscarinic binding was significantly reduced without changes in Kd; nevertheless, carbachol-induced stimulation of formation of inositol phosphate was unaffected. The response to K+ was markedly elevated in the 6-hydroxydopamine-treated animals. Thus, the regulatory effect of A10-septal dopaminergic pathways on the septohippocampal cholinergic innervations is both on the presynaptic and postsynaptic levels.
Yanai
J
J
Melvin A. and Eleanor Ross Laboratory for Studies in Neural Birth Defects, Department of Anatomy and Embryology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Rogel-Fuchs
Y
Y
Pick
C G
CG
Slotkin
T
T
Seidler
F J
FJ
Zahalka
E A
EA
Newman
M E
ME
D000818:Animals; D001921:Brain / Q000502:physiology*; D001923:Brain Chemistry; D002217:Carbachol / Q000494:pharmacology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D007295:Inositol Phosphates / Q000096:biosynthesis; D008297:Male; D051379:Mice; D009434:Neural Pathways / Q000502:physiology; D016627:Oxidopamine; D010275:Parasympathetic Nervous System / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism; D013563:Sympathectomy, Chemical
D007295:Inositol Phosphates; D011976:Receptors, Muscarinic; D016627:Oxidopamine; D002217:Carbachol; D002795:Choline O-Acetyltransferase; D011188:Potassium; D004298:Dopamine