Electrophysiological and neurochemical characterization of neurons of the medial preoptic area in Japanese quail (Coturnix japonica).
Intracellular recordings of medial preoptic neurons demonstrated that most neurons show a spontaneous firing, a linear I-V relationship and low-threshold-like events suppressed by the application of Ni2+. Some neurons had a depolarizing sag of the membrane potential in response to hyperpolarizing current pulses. The majority of the cells exhibited a robust spontaneous synaptic activity suppressed by SR95531 (100 microM), a GABAA receptor antagonist, and/or by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM), an (RS)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate (KA) glutamate receptor antagonist. Most neurons were affected by the application of AMPA (10 microM), kainate (30 microM), N-methyl-D-aspartic acid (NMDA, 10 microM), isoguvacine (a GABAA receptor agonist, 100 microM), dopamine (100 microM), and norepinephrine (100 microM). Biocytin injections coupled to aromatase immunocytochemistry identified 19 recorded neurons including 3 displaying a dense aromatase immunoreactivity. All of them responded to kainate, dopamine, and norepinephrine, while only one responded to isoguvacine and NMDA. Taken together, these results demonstrate a relative electrical and neurochemical homogeneity of the medial preoptic neurons, including a few aromatase-immunoreactive neurons that could be identified by immunocytochemistry after biocytin labeling of the recorded neurons.
Cornil
Charlotte A
CA
Center for Cellular and Molecular Neurobiology, Research Group in Behavioral Neuroendocrinology, University of Liège, 17 Place Delcour (Bat L1), B-4020 Liège, Belgium. Charlotte.Cornil@ulg.ac.be
Seutin
Vincent
V
Motte
Patrick
P
Balthazart
Jacques
J
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001141:Aromatase / Q000378:metabolism; D003370:Coturnix / Q000502:physiology*; D004298:Dopamine / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D007539:Isonicotinic Acids / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011301:Preoptic Area / Q000166:cytology / Q000502:physiology*; D011724:Pyridazines / Q000494:pharmacology; D013566:Sympathomimetics / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018755:GABA Agonists; D018756:GABA Antagonists; D007539:Isonicotinic Acids; D011724:Pyridazines; D013566:Sympathomimetics; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; C049853:gabazine; D001141:Aromatase; D007608:Kainic Acid; D004298:Dopamine; D009638:Norepinephrine; C015300:isoguvacine