Effects of dopamine, D-1 and D-2 dopaminergic agonists on the excitability of hippocampal CA1 pyramidal cells in guinea pig.
In hippocampal pyramidal cells (HPCs), Dopamine (DA) application (1 microM) produced, in 50% of recorded cells, an hyperpolarization of the resting membrane potential (r.m.p.) and an increase of the afterhyperpolarization (AHP) amplitude and duration in 79% of recorded cells. DA-induced effects on both the r.m.p. and AHP were mimicked by bath application of a D-1 selective agonist, SKF 38393 (20 microM). In addition, we have observed that a D-1 selective antagonist such as SCH 23390 (1 microM) abolished the action of both DA and SKF 38393. In contrast, the activation of D-2 receptors through LY 171555 (10 microns) produced, in 50% of cells, a depolarization of the r.m.p. and a depression of the AHP in 67% of recorded cells. These results suggest that the effects observed in hippocampal pyramidal neurons after DA application of micromolar concentration are mediated by D-1 subtype of receptors.
Berretta
N
N
Department of Physiology and Biochemistry G. Moruzzi, University of Pisa, Italy.
Berton
F
F
Bianchi
R
R
Capogna
M
M
Francesconi
W
W
Brunelli
M
M
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology*; D000818:Animals; D004298:Dopamine / Q000494:pharmacology*; D015259:Dopamine Agents / Q000494:pharmacology*; D004594:Electrophysiology; D004873:Ergolines / Q000494:pharmacology*; D006168:Guinea Pigs; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D019257:Quinpirole
D015259:Dopamine Agents; D004873:Ergolines; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D004298:Dopamine