title: Dopamine modulates the afterhyperpolarization in neostriatal neurones.
abstract: Intracellular techniques were used to study the actions of dopaminergic D1 agonists on the afterhyperpolarization (AHP) that follows action potentials in rat neostriatal neurones. Dopamine or Cl-APB (10 microM), or 1-10 microM 6-Cl-PB all increased AHP amplitude. This effect was blocked by 1 microM SCH-23390, a D1 antagonist, but not by 1 microM sulpiride, a D2 antagonist. Both 500 microM dibutyryl cAMP and 5 microM BayK 8644 induced a similar AHP increase. BayK 8644 occluded the effect of agonists. The results suggest that the action of dopamine is mediated via the recently described protein kinase A enhancement of L-type Ca2+ channels. The results partially explain the decrease in firing frequency induced by dopamine and a possible site of antagonism with cholinergic modulation.
authors.affiliation: Departamento de Neurociencias, UNAM, México City, DF, México.
authors.forename: S
authors.initials: S
authors.lastname: Hernández-López
authors.forename: J
authors.initials: J
authors.lastname: Bargas
authors.forename: A
authors.initials: A
authors.lastname: Reyes
authors.forename: E
authors.initials: E
authors.lastname: Galarraga
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology / Q000502:physiology*; D065127:Dopamine D2 Receptor Antagonists; D066298:In Vitro Techniques; D017072:Neostriatum / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors; D017448:Receptors, Dopamine D2 / Q000819:agonists
chemical_list: D002120:Calcium Channel Agonists; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D003994:Bucladesine; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D004298:Dopamine