Intracellular studies of dopamine neurons in vitro: pacemakers modulated by dopamine.
Intracellular recordings from dopamine (DA)-sensitive neurons in rat substantia nigra tissue slices revealed that these neurons exhibit spontaneous pacemaker-like activity. DA-sensitive neurons had higher input resistances, larger time constants and less linear voltage responses to current injection than did non-DA-sensitive neurons in the zona compacta. The administration of DA produced an inhibition of firing rate, a hyperpolarization and a decrease in input resistance. These effects were blocked by (-)sulpiride, a selective D2 antagonist. A reversal potential of -88 +/- 14 mV was calculated for the DA-induced hyperpolarization suggesting the involvement of potassium ions in the mechanism of DA action.
Silva
N L
NL
Department of Pharmacology and Psychiatry, Yale University, School of Medicine, New Haven, CT 06510.
Bunney
B S
BS
D000818:Animals; D004298:Dopamine / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008636:Mesencephalon / Q000166:cytology / Q000187:drug effects; D009474:Neurons / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013469:Sulpiride / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D013779:Tetrodotoxin; D013469:Sulpiride; D004298:Dopamine