Muscarinic receptors modulate N-, P-, and L-type Ca2+ currents in rat striatal neurons through parallel pathways.
Muscarinic modulation of calcium currents was studied in acutely isolated striatal neurons from the adult rat using the whole-cell configuration of the patch-clamp technique. Muscarinic agonists reduced calcium currents through two distinct signaling pathways. One pathway depended upon PTX-sensitive G-proteins and targeted N- and P-type currents. The other pathway depended upon PTX-insensitive G-proteins and was rendered inactive by high intracellular concentrations of BAPTA and targeted L-type currents. The modulation of N- and P-type currents was relieved by strong depolarizing prepulses, whereas the modulation of L-type currents was not. These findings support the proposition that parallel signaling pathways exist between muscarinic receptors and calcium channels.
Howe
A R
AR
Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee, Memphis 38163.
Surmeier
D J
DJ
D000818:Animals; D002118:Calcium / Q000502:physiology*; D003342:Corpus Striatum / Q000166:cytology / Q000502:physiology*; D004594:Electrophysiology; D019204:GTP-Binding Proteins / Q000502:physiology; D008297:Male; D009474:Neurons / Q000502:physiology*; D051381:Rats; D011976:Receptors, Muscarinic / Q000502:physiology*; D015398:Signal Transduction
D011976:Receptors, Muscarinic; D019204:GTP-Binding Proteins; D002118:Calcium