Title : Muscarine depolarizes rat substantia nigra zona compacta and ventral tegmental neurons in vitro through M1-like receptors - Lacey_1990_J.Pharmacol.Exp.Ther_253_395 |
Author(s) : Lacey MG , Calabresi P , North RA |
Ref : Journal of Pharmacology & Experimental Therapeutics , 253 :395 , 1990 |
Abstract :
Intracellular recordings were made from presumed dopamine-containing neurons in slices of rat mesencephalon. Muscarine (3-100 microM) increased the rate of spontaneous action potentials; it also caused a membrane depolarization and, in voltage-clamp, an inward current. Concentration-effect curves to muscarine were shifted rightwards by pirenzepine (0.03-1 microM) with an estimated KD of 14 nM. The inward current caused by muscarine was voltage-dependent. Between about -50 and (-)-65 mV it was associated with a decrease in membrane conductance, but between -70 and -110 mV it was unaccompanied by any change in membrane conductance. Muscarine was without effect on the action potential afterhyperpolarization, or on a slowly developing inward current evoked by step hyperpolarizations of up to 20 mV from -45 mV. Muscarinic depolarizations or inward currents were reduced reversibly or abolished by a low calcium (0.25 mM)/high magnesium (10 mM) solution. It is concluded that muscarinic excitation of dopaminergic neurons is mediated by M1-like receptors. |
PubMedSearch : Lacey_1990_J.Pharmacol.Exp.Ther_253_395 |
PubMedID: 2329522 |
Lacey MG, Calabresi P, North RA (1990)
Muscarine depolarizes rat substantia nigra zona compacta and ventral tegmental neurons in vitro through M1-like receptors
Journal of Pharmacology & Experimental Therapeutics
253 :395
Lacey MG, Calabresi P, North RA (1990)
Journal of Pharmacology & Experimental Therapeutics
253 :395